From 2a545e9e949ca1daad6f724ceaaae20ce281d5a6 Mon Sep 17 00:00:00 2001 From: Heikki Linnakangas Date: Tue, 12 Jun 2018 15:31:39 +0300 Subject: [PATCH 2/4] Move GROUP BY planning code from planner.c to separate file, aggpath.c --- src/backend/optimizer/path/Makefile | 4 +- src/backend/optimizer/path/aggpath.c | 1967 ++++++++++++ src/backend/optimizer/plan/Makefile | 4 +- src/backend/optimizer/plan/planner.c | 5420 +++++++++++----------------------- src/include/nodes/relation.h | 19 + src/include/optimizer/paths.h | 13 + src/include/optimizer/planmain.h | 1 + src/include/optimizer/planner.h | 2 + 8 files changed, 3741 insertions(+), 3689 deletions(-) create mode 100644 src/backend/optimizer/path/aggpath.c diff --git a/src/backend/optimizer/path/Makefile b/src/backend/optimizer/path/Makefile index 6864a62132..21216a621d 100644 --- a/src/backend/optimizer/path/Makefile +++ b/src/backend/optimizer/path/Makefile @@ -12,7 +12,7 @@ subdir = src/backend/optimizer/path top_builddir = ../../../.. include $(top_builddir)/src/Makefile.global -OBJS = allpaths.o clausesel.o costsize.o equivclass.o indxpath.o \ - joinpath.o joinrels.o pathkeys.o tidpath.o +OBJS = aggpath.o allpaths.o clausesel.o costsize.o equivclass.o \ + indxpath.o joinpath.o joinrels.o pathkeys.o tidpath.o include $(top_srcdir)/src/backend/common.mk diff --git a/src/backend/optimizer/path/aggpath.c b/src/backend/optimizer/path/aggpath.c new file mode 100644 index 0000000000..618171b148 --- /dev/null +++ b/src/backend/optimizer/path/aggpath.c @@ -0,0 +1,1967 @@ +/*------------------------------------------------------------------------- + * + * aggpath.c + * Routines to generate paths for processing GROUP BY and aggregates. + * + * XXX + * + * + * Portions Copyright (c) 1996-2018, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * + * IDENTIFICATION + * src/backend/optimizer/path/aggpath.c + * + *------------------------------------------------------------------------- + */ +#include "postgres.h" + +#include + +#include "access/htup_details.h" +#include "catalog/pg_aggregate.h" +#include "catalog/pg_type.h" +#include "executor/nodeAgg.h" +#include "foreign/fdwapi.h" +#include "lib/knapsack.h" +#include "miscadmin.h" +#include "nodes/makefuncs.h" +#include "nodes/nodeFuncs.h" +#include "optimizer/clauses.h" +#include "optimizer/cost.h" +#include "optimizer/pathnode.h" +#include "optimizer/paths.h" +#include "optimizer/planmain.h" +#include "optimizer/planner.h" +#include "optimizer/prep.h" +#include "optimizer/tlist.h" +#include "optimizer/var.h" +#include "parser/parsetree.h" +#include "parser/parse_agg.h" +#include "parser/parse_clause.h" +#include "rewrite/rewriteManip.h" +#include "utils/lsyscache.h" +#include "utils/selfuncs.h" +#include "utils/syscache.h" + +static RelOptInfo *make_grouping_rel(PlannerInfo *root, RelOptInfo *input_rel, + PathTarget *target, bool target_parallel_safe, + Node *havingQual); +static bool is_degenerate_grouping(PlannerInfo *root); +static void create_degenerate_grouping_paths(PlannerInfo *root, + RelOptInfo *input_rel, + RelOptInfo *grouped_rel); +static void create_ordinary_grouping_paths(PlannerInfo *root, + RelOptInfo *input_rel, + RelOptInfo *grouped_rel, + const AggClauseCosts *agg_costs, + grouping_sets_data *gd, + GroupPathExtraData *extra, + RelOptInfo **partially_grouped_rel_p); +static bool can_partial_agg(PlannerInfo *root, + const AggClauseCosts *agg_costs); +static void create_partitionwise_grouping_paths(PlannerInfo *root, + RelOptInfo *input_rel, + RelOptInfo *grouped_rel, + RelOptInfo *partially_grouped_rel, + const AggClauseCosts *agg_costs, + grouping_sets_data *gd, + PartitionwiseAggregateType patype, + GroupPathExtraData *extra); +static bool group_by_has_partkey(RelOptInfo *input_rel, + List *targetList, + List *groupClause); +static RelOptInfo *create_partial_grouping_paths(PlannerInfo *root, + RelOptInfo *grouped_rel, + RelOptInfo *input_rel, + grouping_sets_data *gd, + GroupPathExtraData *extra, + bool force_rel_creation); +static void gather_grouping_paths(PlannerInfo *root, RelOptInfo *rel); +static void add_paths_to_grouping_rel(PlannerInfo *root, RelOptInfo *input_rel, + RelOptInfo *grouped_rel, + RelOptInfo *partially_grouped_rel, + const AggClauseCosts *agg_costs, + grouping_sets_data *gd, + double dNumGroups, + GroupPathExtraData *extra); +static PathTarget *make_partial_grouping_target(PlannerInfo *root, + PathTarget *grouping_target, + Node *havingQual); +static void consider_groupingsets_paths(PlannerInfo *root, + RelOptInfo *grouped_rel, + Path *path, + bool is_sorted, + bool can_hash, + grouping_sets_data *gd, + const AggClauseCosts *agg_costs, + double dNumGroups); + +/* + * Estimate number of groups produced by grouping clauses (1 if not grouping) + * + * path_rows: number of output rows from scan/join step + * gd: grouping sets data including list of grouping sets and their clauses + * target_list: target list containing group clause references + * + * If doing grouping sets, we also annotate the gsets data with the estimates + * for each set and each individual rollup list, with a view to later + * determining whether some combination of them could be hashed instead. + */ +static double +get_number_of_groups(PlannerInfo *root, + double path_rows, + grouping_sets_data *gd, + List *target_list) +{ + Query *parse = root->parse; + double dNumGroups; + + if (parse->groupClause) + { + List *groupExprs; + + if (parse->groupingSets) + { + /* Add up the estimates for each grouping set */ + ListCell *lc; + ListCell *lc2; + + Assert(gd); /* keep Coverity happy */ + + dNumGroups = 0; + + foreach(lc, gd->rollups) + { + RollupData *rollup = lfirst_node(RollupData, lc); + ListCell *lc; + + groupExprs = get_sortgrouplist_exprs(rollup->groupClause, + target_list); + + rollup->numGroups = 0.0; + + forboth(lc, rollup->gsets, lc2, rollup->gsets_data) + { + List *gset = (List *) lfirst(lc); + GroupingSetData *gs = lfirst_node(GroupingSetData, lc2); + double numGroups = estimate_num_groups(root, + groupExprs, + path_rows, + &gset); + + gs->numGroups = numGroups; + rollup->numGroups += numGroups; + } + + dNumGroups += rollup->numGroups; + } + + if (gd->hash_sets_idx) + { + ListCell *lc; + + gd->dNumHashGroups = 0; + + groupExprs = get_sortgrouplist_exprs(parse->groupClause, + target_list); + + forboth(lc, gd->hash_sets_idx, lc2, gd->unsortable_sets) + { + List *gset = (List *) lfirst(lc); + GroupingSetData *gs = lfirst_node(GroupingSetData, lc2); + double numGroups = estimate_num_groups(root, + groupExprs, + path_rows, + &gset); + + gs->numGroups = numGroups; + gd->dNumHashGroups += numGroups; + } + + dNumGroups += gd->dNumHashGroups; + } + } + else + { + /* Plain GROUP BY */ + groupExprs = get_sortgrouplist_exprs(parse->groupClause, + target_list); + + dNumGroups = estimate_num_groups(root, groupExprs, path_rows, + NULL); + } + } + else if (parse->groupingSets) + { + /* Empty grouping sets ... one result row for each one */ + dNumGroups = list_length(parse->groupingSets); + } + else if (parse->hasAggs || root->hasHavingQual) + { + /* Plain aggregation, one result row */ + dNumGroups = 1; + } + else + { + /* Not grouping */ + dNumGroups = 1; + } + + return dNumGroups; +} + +/* + * estimate_hashagg_tablesize + * estimate the number of bytes that a hash aggregate hashtable will + * require based on the agg_costs, path width and dNumGroups. + * + * XXX this may be over-estimating the size now that hashagg knows to omit + * unneeded columns from the hashtable. Also for mixed-mode grouping sets, + * grouping columns not in the hashed set are counted here even though hashagg + * won't store them. Is this a problem? + */ +static Size +estimate_hashagg_tablesize(Path *path, const AggClauseCosts *agg_costs, + double dNumGroups) +{ + Size hashentrysize; + + /* Estimate per-hash-entry space at tuple width... */ + hashentrysize = MAXALIGN(path->pathtarget->width) + + MAXALIGN(SizeofMinimalTupleHeader); + + /* plus space for pass-by-ref transition values... */ + hashentrysize += agg_costs->transitionSpace; + /* plus the per-hash-entry overhead */ + hashentrysize += hash_agg_entry_size(agg_costs->numAggs); + + /* + * Note that this disregards the effect of fill-factor and growth policy + * of the hash-table. That's probably ok, given default the default + * fill-factor is relatively high. It'd be hard to meaningfully factor in + * "double-in-size" growth policies here. + */ + return hashentrysize * dNumGroups; +} + +/* + * create_grouping_paths + * + * Build a new upperrel containing Paths for grouping and/or aggregation. + * Along the way, we also build an upperrel for Paths which are partially + * grouped and/or aggregated. A partially grouped and/or aggregated path + * needs a FinalizeAggregate node to complete the aggregation. Currently, + * the only partially grouped paths we build are also partial paths; that + * is, they need a Gather and then a FinalizeAggregate. + * + * input_rel: contains the source-data Paths + * target: the pathtarget for the result Paths to compute + * agg_costs: cost info about all aggregates in query (in AGGSPLIT_SIMPLE mode) + * gd: grouping sets data including list of grouping sets and their clauses + * + * Note: all Paths in input_rel are expected to return the target computed + * by make_group_input_target. + */ +RelOptInfo * +create_grouping_paths(PlannerInfo *root, + RelOptInfo *input_rel, + PathTarget *target, + bool target_parallel_safe, + const AggClauseCosts *agg_costs, + grouping_sets_data *gd) +{ + Query *parse = root->parse; + RelOptInfo *grouped_rel; + RelOptInfo *partially_grouped_rel; + + /* + * Create grouping relation to hold fully aggregated grouping and/or + * aggregation paths. + */ + grouped_rel = make_grouping_rel(root, input_rel, target, + target_parallel_safe, parse->havingQual); + + /* + * Create either paths for a degenerate grouping or paths for ordinary + * grouping, as appropriate. + */ + if (is_degenerate_grouping(root)) + create_degenerate_grouping_paths(root, input_rel, grouped_rel); + else + { + int flags = 0; + GroupPathExtraData extra; + + /* + * Determine whether it's possible to perform sort-based + * implementations of grouping. (Note that if groupClause is empty, + * grouping_is_sortable() is trivially true, and all the + * pathkeys_contained_in() tests will succeed too, so that we'll + * consider every surviving input path.) + * + * If we have grouping sets, we might be able to sort some but not all + * of them; in this case, we need can_sort to be true as long as we + * must consider any sorted-input plan. + */ + if ((gd && gd->rollups != NIL) + || grouping_is_sortable(parse->groupClause)) + flags |= GROUPING_CAN_USE_SORT; + + /* + * Determine whether we should consider hash-based implementations of + * grouping. + * + * Hashed aggregation only applies if we're grouping. If we have + * grouping sets, some groups might be hashable but others not; in + * this case we set can_hash true as long as there is nothing globally + * preventing us from hashing (and we should therefore consider plans + * with hashes). + * + * Executor doesn't support hashed aggregation with DISTINCT or ORDER + * BY aggregates. (Doing so would imply storing *all* the input + * values in the hash table, and/or running many sorts in parallel, + * either of which seems like a certain loser.) We similarly don't + * support ordered-set aggregates in hashed aggregation, but that case + * is also included in the numOrderedAggs count. + * + * Note: grouping_is_hashable() is much more expensive to check than + * the other gating conditions, so we want to do it last. + */ + if ((parse->groupClause != NIL && + agg_costs->numOrderedAggs == 0 && + (gd ? gd->any_hashable : grouping_is_hashable(parse->groupClause)))) + flags |= GROUPING_CAN_USE_HASH; + + /* + * Determine whether partial aggregation is possible. + */ + if (can_partial_agg(root, agg_costs)) + flags |= GROUPING_CAN_PARTIAL_AGG; + + extra.flags = flags; + extra.target_parallel_safe = target_parallel_safe; + extra.havingQual = parse->havingQual; + extra.targetList = parse->targetList; + extra.partial_costs_set = false; + + /* + * Determine whether partitionwise aggregation is in theory possible. + * It can be disabled by the user, and for now, we don't try to + * support grouping sets. create_ordinary_grouping_paths() will check + * additional conditions, such as whether input_rel is partitioned. + */ + if (enable_partitionwise_aggregate && !parse->groupingSets) + extra.patype = PARTITIONWISE_AGGREGATE_FULL; + else + extra.patype = PARTITIONWISE_AGGREGATE_NONE; + + create_ordinary_grouping_paths(root, input_rel, grouped_rel, + agg_costs, gd, &extra, + &partially_grouped_rel); + } + + set_cheapest(grouped_rel); + return grouped_rel; +} + +/* + * make_grouping_rel + * + * Create a new grouping rel and set basic properties. + * + * input_rel represents the underlying scan/join relation. + * target is the output expected from the grouping relation. + */ +static RelOptInfo * +make_grouping_rel(PlannerInfo *root, RelOptInfo *input_rel, + PathTarget *target, bool target_parallel_safe, + Node *havingQual) +{ + RelOptInfo *grouped_rel; + + if (IS_OTHER_REL(input_rel)) + { + grouped_rel = fetch_upper_rel(root, UPPERREL_GROUP_AGG, + input_rel->relids); + grouped_rel->reloptkind = RELOPT_OTHER_UPPER_REL; + } + else + { + /* + * By tradition, the relids set for the main grouping relation is + * NULL. (This could be changed, but might require adjustments + * elsewhere.) + */ + grouped_rel = fetch_upper_rel(root, UPPERREL_GROUP_AGG, NULL); + } + + /* Set target. */ + grouped_rel->reltarget = target; + + /* + * If the input relation is not parallel-safe, then the grouped relation + * can't be parallel-safe, either. Otherwise, it's parallel-safe if the + * target list and HAVING quals are parallel-safe. + */ + if (input_rel->consider_parallel && target_parallel_safe && + is_parallel_safe(root, (Node *) havingQual)) + grouped_rel->consider_parallel = true; + + /* + * If the input rel belongs to a single FDW, so does the grouped rel. + */ + grouped_rel->serverid = input_rel->serverid; + grouped_rel->userid = input_rel->userid; + grouped_rel->useridiscurrent = input_rel->useridiscurrent; + grouped_rel->fdwroutine = input_rel->fdwroutine; + + return grouped_rel; +} + +/* + * is_degenerate_grouping + * + * A degenerate grouping is one in which the query has a HAVING qual and/or + * grouping sets, but no aggregates and no GROUP BY (which implies that the + * grouping sets are all empty). + */ +static bool +is_degenerate_grouping(PlannerInfo *root) +{ + Query *parse = root->parse; + + return (root->hasHavingQual || parse->groupingSets) && + !parse->hasAggs && parse->groupClause == NIL; +} + +/* + * create_degenerate_grouping_paths + * + * When the grouping is degenerate (see is_degenerate_grouping), we are + * supposed to emit either zero or one row for each grouping set depending on + * whether HAVING succeeds. Furthermore, there cannot be any variables in + * either HAVING or the targetlist, so we actually do not need the FROM table + * at all! We can just throw away the plan-so-far and generate a Result node. + * This is a sufficiently unusual corner case that it's not worth contorting + * the structure of this module to avoid having to generate the earlier paths + * in the first place. + */ +static void +create_degenerate_grouping_paths(PlannerInfo *root, RelOptInfo *input_rel, + RelOptInfo *grouped_rel) +{ + Query *parse = root->parse; + int nrows; + Path *path; + + nrows = list_length(parse->groupingSets); + if (nrows > 1) + { + /* + * Doesn't seem worthwhile writing code to cons up a generate_series + * or a values scan to emit multiple rows. Instead just make N clones + * and append them. (With a volatile HAVING clause, this means you + * might get between 0 and N output rows. Offhand I think that's + * desired.) + */ + List *paths = NIL; + + while (--nrows >= 0) + { + path = (Path *) + create_result_path(root, grouped_rel, + grouped_rel->reltarget, + (List *) parse->havingQual); + paths = lappend(paths, path); + } + path = (Path *) + create_append_path(root, + grouped_rel, + paths, + NIL, + NULL, + 0, + false, + NIL, + -1); + } + else + { + /* No grouping sets, or just one, so one output row */ + path = (Path *) + create_result_path(root, grouped_rel, + grouped_rel->reltarget, + (List *) parse->havingQual); + } + + add_path(grouped_rel, path); +} + +/* + * create_ordinary_grouping_paths + * + * Create grouping paths for the ordinary (that is, non-degenerate) case. + * + * We need to consider sorted and hashed aggregation in the same function, + * because otherwise (1) it would be harder to throw an appropriate error + * message if neither way works, and (2) we should not allow hashtable size + * considerations to dissuade us from using hashing if sorting is not possible. + * + * *partially_grouped_rel_p will be set to the partially grouped rel which this + * function creates, or to NULL if it doesn't create one. + */ +static void +create_ordinary_grouping_paths(PlannerInfo *root, RelOptInfo *input_rel, + RelOptInfo *grouped_rel, + const AggClauseCosts *agg_costs, + grouping_sets_data *gd, + GroupPathExtraData *extra, + RelOptInfo **partially_grouped_rel_p) +{ + Path *cheapest_path = input_rel->cheapest_total_path; + RelOptInfo *partially_grouped_rel = NULL; + double dNumGroups; + PartitionwiseAggregateType patype = PARTITIONWISE_AGGREGATE_NONE; + + /* + * If this is the topmost grouping relation or if the parent relation is + * doing some form of partitionwise aggregation, then we may be able to do + * it at this level also. However, if the input relation is not + * partitioned, partitionwise aggregate is impossible, and if it is dummy, + * partitionwise aggregate is pointless. + */ + if (extra->patype != PARTITIONWISE_AGGREGATE_NONE && + input_rel->part_scheme && input_rel->part_rels && + !IS_DUMMY_REL(input_rel)) + { + /* + * If this is the topmost relation or if the parent relation is doing + * full partitionwise aggregation, then we can do full partitionwise + * aggregation provided that the GROUP BY clause contains all of the + * partitioning columns at this level. Otherwise, we can do at most + * partial partitionwise aggregation. But if partial aggregation is + * not supported in general then we can't use it for partitionwise + * aggregation either. + */ + if (extra->patype == PARTITIONWISE_AGGREGATE_FULL && + group_by_has_partkey(input_rel, extra->targetList, + root->parse->groupClause)) + patype = PARTITIONWISE_AGGREGATE_FULL; + else if ((extra->flags & GROUPING_CAN_PARTIAL_AGG) != 0) + patype = PARTITIONWISE_AGGREGATE_PARTIAL; + else + patype = PARTITIONWISE_AGGREGATE_NONE; + } + + /* + * Before generating paths for grouped_rel, we first generate any possible + * partially grouped paths; that way, later code can easily consider both + * parallel and non-parallel approaches to grouping. + */ + if ((extra->flags & GROUPING_CAN_PARTIAL_AGG) != 0) + { + bool force_rel_creation; + + /* + * If we're doing partitionwise aggregation at this level, force + * creation of a partially_grouped_rel so we can add partitionwise + * paths to it. + */ + force_rel_creation = (patype == PARTITIONWISE_AGGREGATE_PARTIAL); + + partially_grouped_rel = + create_partial_grouping_paths(root, + grouped_rel, + input_rel, + gd, + extra, + force_rel_creation); + } + + /* Set out parameter. */ + *partially_grouped_rel_p = partially_grouped_rel; + + /* Apply partitionwise aggregation technique, if possible. */ + if (patype != PARTITIONWISE_AGGREGATE_NONE) + create_partitionwise_grouping_paths(root, input_rel, grouped_rel, + partially_grouped_rel, agg_costs, + gd, patype, extra); + + /* If we are doing partial aggregation only, return. */ + if (extra->patype == PARTITIONWISE_AGGREGATE_PARTIAL) + { + Assert(partially_grouped_rel); + + if (partially_grouped_rel->pathlist) + set_cheapest(partially_grouped_rel); + + return; + } + + /* Gather any partially grouped partial paths. */ + if (partially_grouped_rel && partially_grouped_rel->partial_pathlist) + { + gather_grouping_paths(root, partially_grouped_rel); + set_cheapest(partially_grouped_rel); + } + + /* + * Estimate number of groups. + */ + dNumGroups = get_number_of_groups(root, + cheapest_path->rows, + gd, + extra->targetList); + + /* Build final grouping paths */ + add_paths_to_grouping_rel(root, input_rel, grouped_rel, + partially_grouped_rel, agg_costs, gd, + dNumGroups, extra); + + /* Give a helpful error if we failed to find any implementation */ + if (grouped_rel->pathlist == NIL) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("could not implement GROUP BY"), + errdetail("Some of the datatypes only support hashing, while others only support sorting."))); + + /* + * If there is an FDW that's responsible for all baserels of the query, + * let it consider adding ForeignPaths. + */ + if (grouped_rel->fdwroutine && + grouped_rel->fdwroutine->GetForeignUpperPaths) + grouped_rel->fdwroutine->GetForeignUpperPaths(root, UPPERREL_GROUP_AGG, + input_rel, grouped_rel, + extra); + + /* Let extensions possibly add some more paths */ + if (create_upper_paths_hook) + (*create_upper_paths_hook) (root, UPPERREL_GROUP_AGG, + input_rel, grouped_rel, + extra); +} + +/* + * add_paths_to_grouping_rel + * + * Add non-partial paths to grouping relation. + */ +static void +add_paths_to_grouping_rel(PlannerInfo *root, RelOptInfo *input_rel, + RelOptInfo *grouped_rel, + RelOptInfo *partially_grouped_rel, + const AggClauseCosts *agg_costs, + grouping_sets_data *gd, double dNumGroups, + GroupPathExtraData *extra) +{ + Query *parse = root->parse; + Path *cheapest_path = input_rel->cheapest_total_path; + ListCell *lc; + bool can_hash = (extra->flags & GROUPING_CAN_USE_HASH) != 0; + bool can_sort = (extra->flags & GROUPING_CAN_USE_SORT) != 0; + List *havingQual = (List *) extra->havingQual; + AggClauseCosts *agg_final_costs = &extra->agg_final_costs; + + if (can_sort) + { + /* + * Use any available suitably-sorted path as input, and also consider + * sorting the cheapest-total path. + */ + foreach(lc, input_rel->pathlist) + { + Path *path = (Path *) lfirst(lc); + bool is_sorted; + + is_sorted = pathkeys_contained_in(root->group_pathkeys, + path->pathkeys); + if (path == cheapest_path || is_sorted) + { + /* Sort the cheapest-total path if it isn't already sorted */ + if (!is_sorted) + path = (Path *) create_sort_path(root, + grouped_rel, + path, + root->group_pathkeys, + -1.0); + + /* Now decide what to stick atop it */ + if (parse->groupingSets) + { + consider_groupingsets_paths(root, grouped_rel, + path, true, can_hash, + gd, agg_costs, dNumGroups); + } + else if (parse->hasAggs) + { + /* + * We have aggregation, possibly with plain GROUP BY. Make + * an AggPath. + */ + add_path(grouped_rel, (Path *) + create_agg_path(root, + grouped_rel, + path, + grouped_rel->reltarget, + parse->groupClause ? AGG_SORTED : AGG_PLAIN, + AGGSPLIT_SIMPLE, + parse->groupClause, + havingQual, + agg_costs, + dNumGroups)); + } + else if (parse->groupClause) + { + /* + * We have GROUP BY without aggregation or grouping sets. + * Make a GroupPath. + */ + add_path(grouped_rel, (Path *) + create_group_path(root, + grouped_rel, + path, + parse->groupClause, + havingQual, + dNumGroups)); + } + else + { + /* Other cases should have been handled above */ + Assert(false); + } + } + } + + /* + * Instead of operating directly on the input relation, we can + * consider finalizing a partially aggregated path. + */ + if (partially_grouped_rel != NULL) + { + foreach(lc, partially_grouped_rel->pathlist) + { + Path *path = (Path *) lfirst(lc); + + /* + * Insert a Sort node, if required. But there's no point in + * sorting anything but the cheapest path. + */ + if (!pathkeys_contained_in(root->group_pathkeys, path->pathkeys)) + { + if (path != partially_grouped_rel->cheapest_total_path) + continue; + path = (Path *) create_sort_path(root, + grouped_rel, + path, + root->group_pathkeys, + -1.0); + } + + if (parse->hasAggs) + add_path(grouped_rel, (Path *) + create_agg_path(root, + grouped_rel, + path, + grouped_rel->reltarget, + parse->groupClause ? AGG_SORTED : AGG_PLAIN, + AGGSPLIT_FINAL_DESERIAL, + parse->groupClause, + havingQual, + agg_final_costs, + dNumGroups)); + else + add_path(grouped_rel, (Path *) + create_group_path(root, + grouped_rel, + path, + parse->groupClause, + havingQual, + dNumGroups)); + } + } + } + + if (can_hash) + { + Size hashaggtablesize; + + if (parse->groupingSets) + { + /* + * Try for a hash-only groupingsets path over unsorted input. + */ + consider_groupingsets_paths(root, grouped_rel, + cheapest_path, false, true, + gd, agg_costs, dNumGroups); + } + else + { + hashaggtablesize = estimate_hashagg_tablesize(cheapest_path, + agg_costs, + dNumGroups); + + /* + * Provided that the estimated size of the hashtable does not + * exceed work_mem, we'll generate a HashAgg Path, although if we + * were unable to sort above, then we'd better generate a Path, so + * that we at least have one. + */ + if (hashaggtablesize < work_mem * 1024L || + grouped_rel->pathlist == NIL) + { + /* + * We just need an Agg over the cheapest-total input path, + * since input order won't matter. + */ + add_path(grouped_rel, (Path *) + create_agg_path(root, grouped_rel, + cheapest_path, + grouped_rel->reltarget, + AGG_HASHED, + AGGSPLIT_SIMPLE, + parse->groupClause, + havingQual, + agg_costs, + dNumGroups)); + } + } + + /* + * Generate a Finalize HashAgg Path atop of the cheapest partially + * grouped path, assuming there is one. Once again, we'll only do this + * if it looks as though the hash table won't exceed work_mem. + */ + if (partially_grouped_rel && partially_grouped_rel->pathlist) + { + Path *path = partially_grouped_rel->cheapest_total_path; + + hashaggtablesize = estimate_hashagg_tablesize(path, + agg_final_costs, + dNumGroups); + + if (hashaggtablesize < work_mem * 1024L) + add_path(grouped_rel, (Path *) + create_agg_path(root, + grouped_rel, + path, + grouped_rel->reltarget, + AGG_HASHED, + AGGSPLIT_FINAL_DESERIAL, + parse->groupClause, + havingQual, + agg_final_costs, + dNumGroups)); + } + } + + /* + * When partitionwise aggregate is used, we might have fully aggregated + * paths in the partial pathlist, because add_paths_to_append_rel() will + * consider a path for grouped_rel consisting of a Parallel Append of + * non-partial paths from each child. + */ + if (grouped_rel->partial_pathlist != NIL) + gather_grouping_paths(root, grouped_rel); +} + +/* + * can_partial_agg + * + * Determines whether or not partial grouping and/or aggregation is possible. + * Returns true when possible, false otherwise. + */ +static bool +can_partial_agg(PlannerInfo *root, const AggClauseCosts *agg_costs) +{ + Query *parse = root->parse; + + if (!parse->hasAggs && parse->groupClause == NIL) + { + /* + * We don't know how to do parallel aggregation unless we have either + * some aggregates or a grouping clause. + */ + return false; + } + else if (parse->groupingSets) + { + /* We don't know how to do grouping sets in parallel. */ + return false; + } + else if (agg_costs->hasNonPartial || agg_costs->hasNonSerial) + { + /* Insufficient support for partial mode. */ + return false; + } + + /* Everything looks good. */ + return true; +} + + +/* + * make_partial_grouping_target + * Generate appropriate PathTarget for output of partial aggregate + * (or partial grouping, if there are no aggregates) nodes. + * + * A partial aggregation node needs to emit all the same aggregates that + * a regular aggregation node would, plus any aggregates used in HAVING; + * except that the Aggref nodes should be marked as partial aggregates. + * + * In addition, we'd better emit any Vars and PlaceholderVars that are + * used outside of Aggrefs in the aggregation tlist and HAVING. (Presumably, + * these would be Vars that are grouped by or used in grouping expressions.) + * + * grouping_target is the tlist to be emitted by the topmost aggregation step. + * havingQual represents the HAVING clause. + */ +static PathTarget * +make_partial_grouping_target(PlannerInfo *root, + PathTarget *grouping_target, + Node *havingQual) +{ + Query *parse = root->parse; + PathTarget *partial_target; + List *non_group_cols; + List *non_group_exprs; + int i; + ListCell *lc; + + partial_target = create_empty_pathtarget(); + non_group_cols = NIL; + + i = 0; + foreach(lc, grouping_target->exprs) + { + Expr *expr = (Expr *) lfirst(lc); + Index sgref = get_pathtarget_sortgroupref(grouping_target, i); + + if (sgref && parse->groupClause && + get_sortgroupref_clause_noerr(sgref, parse->groupClause) != NULL) + { + /* + * It's a grouping column, so add it to the partial_target as-is. + * (This allows the upper agg step to repeat the grouping calcs.) + */ + add_column_to_pathtarget(partial_target, expr, sgref); + } + else + { + /* + * Non-grouping column, so just remember the expression for later + * call to pull_var_clause. + */ + non_group_cols = lappend(non_group_cols, expr); + } + + i++; + } + + /* + * If there's a HAVING clause, we'll need the Vars/Aggrefs it uses, too. + */ + if (havingQual) + non_group_cols = lappend(non_group_cols, havingQual); + + /* + * Pull out all the Vars, PlaceHolderVars, and Aggrefs mentioned in + * non-group cols (plus HAVING), and add them to the partial_target if not + * already present. (An expression used directly as a GROUP BY item will + * be present already.) Note this includes Vars used in resjunk items, so + * we are covering the needs of ORDER BY and window specifications. + */ + non_group_exprs = pull_var_clause((Node *) non_group_cols, + PVC_INCLUDE_AGGREGATES | + PVC_RECURSE_WINDOWFUNCS | + PVC_INCLUDE_PLACEHOLDERS); + + add_new_columns_to_pathtarget(partial_target, non_group_exprs); + + /* + * Adjust Aggrefs to put them in partial mode. At this point all Aggrefs + * are at the top level of the target list, so we can just scan the list + * rather than recursing through the expression trees. + */ + foreach(lc, partial_target->exprs) + { + Aggref *aggref = (Aggref *) lfirst(lc); + + if (IsA(aggref, Aggref)) + { + Aggref *newaggref; + + /* + * We shouldn't need to copy the substructure of the Aggref node, + * but flat-copy the node itself to avoid damaging other trees. + */ + newaggref = makeNode(Aggref); + memcpy(newaggref, aggref, sizeof(Aggref)); + + /* For now, assume serialization is required */ + mark_partial_aggref(newaggref, AGGSPLIT_INITIAL_SERIAL); + + lfirst(lc) = newaggref; + } + } + + /* clean up cruft */ + list_free(non_group_exprs); + list_free(non_group_cols); + + /* XXX this causes some redundant cost calculation ... */ + return set_pathtarget_cost_width(root, partial_target); +} + +/* + * create_partial_grouping_paths + * + * Create a new upper relation representing the result of partial aggregation + * and populate it with appropriate paths. Note that we don't finalize the + * lists of paths here, so the caller can add additional partial or non-partial + * paths and must afterward call gather_grouping_paths and set_cheapest on + * the returned upper relation. + * + * All paths for this new upper relation -- both partial and non-partial -- + * have been partially aggregated but require a subsequent FinalizeAggregate + * step. + * + * NB: This function is allowed to return NULL if it determines that there is + * no real need to create a new RelOptInfo. + */ +static RelOptInfo * +create_partial_grouping_paths(PlannerInfo *root, + RelOptInfo *grouped_rel, + RelOptInfo *input_rel, + grouping_sets_data *gd, + GroupPathExtraData *extra, + bool force_rel_creation) +{ + Query *parse = root->parse; + RelOptInfo *partially_grouped_rel; + AggClauseCosts *agg_partial_costs = &extra->agg_partial_costs; + AggClauseCosts *agg_final_costs = &extra->agg_final_costs; + Path *cheapest_partial_path = NULL; + Path *cheapest_total_path = NULL; + double dNumPartialGroups = 0; + double dNumPartialPartialGroups = 0; + ListCell *lc; + bool can_hash = (extra->flags & GROUPING_CAN_USE_HASH) != 0; + bool can_sort = (extra->flags & GROUPING_CAN_USE_SORT) != 0; + + /* + * Consider whether we should generate partially aggregated non-partial + * paths. We can only do this if we have a non-partial path, and only if + * the parent of the input rel is performing partial partitionwise + * aggregation. (Note that extra->patype is the type of partitionwise + * aggregation being used at the parent level, not this level.) + */ + if (input_rel->pathlist != NIL && + extra->patype == PARTITIONWISE_AGGREGATE_PARTIAL) + cheapest_total_path = input_rel->cheapest_total_path; + + /* + * If parallelism is possible for grouped_rel, then we should consider + * generating partially-grouped partial paths. However, if the input rel + * has no partial paths, then we can't. + */ + if (grouped_rel->consider_parallel && input_rel->partial_pathlist != NIL) + cheapest_partial_path = linitial(input_rel->partial_pathlist); + + /* + * If we can't partially aggregate partial paths, and we can't partially + * aggregate non-partial paths, then don't bother creating the new + * RelOptInfo at all, unless the caller specified force_rel_creation. + */ + if (cheapest_total_path == NULL && + cheapest_partial_path == NULL && + !force_rel_creation) + return NULL; + + /* + * Build a new upper relation to represent the result of partially + * aggregating the rows from the input relation. + */ + partially_grouped_rel = fetch_upper_rel(root, + UPPERREL_PARTIAL_GROUP_AGG, + grouped_rel->relids); + partially_grouped_rel->consider_parallel = + grouped_rel->consider_parallel; + partially_grouped_rel->reloptkind = grouped_rel->reloptkind; + partially_grouped_rel->serverid = grouped_rel->serverid; + partially_grouped_rel->userid = grouped_rel->userid; + partially_grouped_rel->useridiscurrent = grouped_rel->useridiscurrent; + partially_grouped_rel->fdwroutine = grouped_rel->fdwroutine; + + /* + * Build target list for partial aggregate paths. These paths cannot just + * emit the same tlist as regular aggregate paths, because (1) we must + * include Vars and Aggrefs needed in HAVING, which might not appear in + * the result tlist, and (2) the Aggrefs must be set in partial mode. + */ + partially_grouped_rel->reltarget = + make_partial_grouping_target(root, grouped_rel->reltarget, + extra->havingQual); + + if (!extra->partial_costs_set) + { + /* + * Collect statistics about aggregates for estimating costs of + * performing aggregation in parallel. + */ + MemSet(agg_partial_costs, 0, sizeof(AggClauseCosts)); + MemSet(agg_final_costs, 0, sizeof(AggClauseCosts)); + if (parse->hasAggs) + { + List *partial_target_exprs; + + /* partial phase */ + partial_target_exprs = partially_grouped_rel->reltarget->exprs; + get_agg_clause_costs(root, (Node *) partial_target_exprs, + AGGSPLIT_INITIAL_SERIAL, + agg_partial_costs); + + /* final phase */ + get_agg_clause_costs(root, (Node *) grouped_rel->reltarget->exprs, + AGGSPLIT_FINAL_DESERIAL, + agg_final_costs); + get_agg_clause_costs(root, extra->havingQual, + AGGSPLIT_FINAL_DESERIAL, + agg_final_costs); + } + + extra->partial_costs_set = true; + } + + /* Estimate number of partial groups. */ + if (cheapest_total_path != NULL) + dNumPartialGroups = + get_number_of_groups(root, + cheapest_total_path->rows, + gd, + extra->targetList); + if (cheapest_partial_path != NULL) + dNumPartialPartialGroups = + get_number_of_groups(root, + cheapest_partial_path->rows, + gd, + extra->targetList); + + if (can_sort && cheapest_total_path != NULL) + { + /* This should have been checked previously */ + Assert(parse->hasAggs || parse->groupClause); + + /* + * Use any available suitably-sorted path as input, and also consider + * sorting the cheapest partial path. + */ + foreach(lc, input_rel->pathlist) + { + Path *path = (Path *) lfirst(lc); + bool is_sorted; + + is_sorted = pathkeys_contained_in(root->group_pathkeys, + path->pathkeys); + if (path == cheapest_total_path || is_sorted) + { + /* Sort the cheapest partial path, if it isn't already */ + if (!is_sorted) + path = (Path *) create_sort_path(root, + partially_grouped_rel, + path, + root->group_pathkeys, + -1.0); + + if (parse->hasAggs) + add_path(partially_grouped_rel, (Path *) + create_agg_path(root, + partially_grouped_rel, + path, + partially_grouped_rel->reltarget, + parse->groupClause ? AGG_SORTED : AGG_PLAIN, + AGGSPLIT_INITIAL_SERIAL, + parse->groupClause, + NIL, + agg_partial_costs, + dNumPartialGroups)); + else + add_path(partially_grouped_rel, (Path *) + create_group_path(root, + partially_grouped_rel, + path, + parse->groupClause, + NIL, + dNumPartialGroups)); + } + } + } + + if (can_sort && cheapest_partial_path != NULL) + { + /* Similar to above logic, but for partial paths. */ + foreach(lc, input_rel->partial_pathlist) + { + Path *path = (Path *) lfirst(lc); + bool is_sorted; + + is_sorted = pathkeys_contained_in(root->group_pathkeys, + path->pathkeys); + if (path == cheapest_partial_path || is_sorted) + { + /* Sort the cheapest partial path, if it isn't already */ + if (!is_sorted) + path = (Path *) create_sort_path(root, + partially_grouped_rel, + path, + root->group_pathkeys, + -1.0); + + if (parse->hasAggs) + add_partial_path(partially_grouped_rel, (Path *) + create_agg_path(root, + partially_grouped_rel, + path, + partially_grouped_rel->reltarget, + parse->groupClause ? AGG_SORTED : AGG_PLAIN, + AGGSPLIT_INITIAL_SERIAL, + parse->groupClause, + NIL, + agg_partial_costs, + dNumPartialPartialGroups)); + else + add_partial_path(partially_grouped_rel, (Path *) + create_group_path(root, + partially_grouped_rel, + path, + parse->groupClause, + NIL, + dNumPartialPartialGroups)); + } + } + } + + if (can_hash && cheapest_total_path != NULL) + { + Size hashaggtablesize; + + /* Checked above */ + Assert(parse->hasAggs || parse->groupClause); + + hashaggtablesize = + estimate_hashagg_tablesize(cheapest_total_path, + agg_partial_costs, + dNumPartialGroups); + + /* + * Tentatively produce a partial HashAgg Path, depending on if it + * looks as if the hash table will fit in work_mem. + */ + if (hashaggtablesize < work_mem * 1024L && + cheapest_total_path != NULL) + { + add_path(partially_grouped_rel, (Path *) + create_agg_path(root, + partially_grouped_rel, + cheapest_total_path, + partially_grouped_rel->reltarget, + AGG_HASHED, + AGGSPLIT_INITIAL_SERIAL, + parse->groupClause, + NIL, + agg_partial_costs, + dNumPartialGroups)); + } + } + + if (can_hash && cheapest_partial_path != NULL) + { + Size hashaggtablesize; + + hashaggtablesize = + estimate_hashagg_tablesize(cheapest_partial_path, + agg_partial_costs, + dNumPartialPartialGroups); + + /* Do the same for partial paths. */ + if (hashaggtablesize < work_mem * 1024L && + cheapest_partial_path != NULL) + { + add_partial_path(partially_grouped_rel, (Path *) + create_agg_path(root, + partially_grouped_rel, + cheapest_partial_path, + partially_grouped_rel->reltarget, + AGG_HASHED, + AGGSPLIT_INITIAL_SERIAL, + parse->groupClause, + NIL, + agg_partial_costs, + dNumPartialPartialGroups)); + } + } + + /* + * If there is an FDW that's responsible for all baserels of the query, + * let it consider adding partially grouped ForeignPaths. + */ + if (partially_grouped_rel->fdwroutine && + partially_grouped_rel->fdwroutine->GetForeignUpperPaths) + { + FdwRoutine *fdwroutine = partially_grouped_rel->fdwroutine; + + fdwroutine->GetForeignUpperPaths(root, + UPPERREL_PARTIAL_GROUP_AGG, + input_rel, partially_grouped_rel, + extra); + } + + return partially_grouped_rel; +} + +/* + * Generate Gather and Gather Merge paths for a grouping relation or partial + * grouping relation. + * + * generate_gather_paths does most of the work, but we also consider a special + * case: we could try sorting the data by the group_pathkeys and then applying + * Gather Merge. + * + * NB: This function shouldn't be used for anything other than a grouped or + * partially grouped relation not only because of the fact that it explicitly + * references group_pathkeys but we pass "true" as the third argument to + * generate_gather_paths(). + */ +static void +gather_grouping_paths(PlannerInfo *root, RelOptInfo *rel) +{ + Path *cheapest_partial_path; + + /* Try Gather for unordered paths and Gather Merge for ordered ones. */ + generate_gather_paths(root, rel, true); + + /* Try cheapest partial path + explicit Sort + Gather Merge. */ + cheapest_partial_path = linitial(rel->partial_pathlist); + if (!pathkeys_contained_in(root->group_pathkeys, + cheapest_partial_path->pathkeys)) + { + Path *path; + double total_groups; + + total_groups = + cheapest_partial_path->rows * cheapest_partial_path->parallel_workers; + path = (Path *) create_sort_path(root, rel, cheapest_partial_path, + root->group_pathkeys, + -1.0); + path = (Path *) + create_gather_merge_path(root, + rel, + path, + rel->reltarget, + root->group_pathkeys, + NULL, + &total_groups); + + add_path(rel, path); + } +} + +/* + * create_partitionwise_grouping_paths + * + * If the partition keys of input relation are part of the GROUP BY clause, all + * the rows belonging to a given group come from a single partition. This + * allows aggregation/grouping over a partitioned relation to be broken down + * into aggregation/grouping on each partition. This should be no worse, and + * often better, than the normal approach. + * + * However, if the GROUP BY clause does not contain all the partition keys, + * rows from a given group may be spread across multiple partitions. In that + * case, we perform partial aggregation for each group, append the results, + * and then finalize aggregation. This is less certain to win than the + * previous case. It may win if the PartialAggregate stage greatly reduces + * the number of groups, because fewer rows will pass through the Append node. + * It may lose if we have lots of small groups. + */ +static void +create_partitionwise_grouping_paths(PlannerInfo *root, + RelOptInfo *input_rel, + RelOptInfo *grouped_rel, + RelOptInfo *partially_grouped_rel, + const AggClauseCosts *agg_costs, + grouping_sets_data *gd, + PartitionwiseAggregateType patype, + GroupPathExtraData *extra) +{ + int nparts = input_rel->nparts; + int cnt_parts; + List *grouped_live_children = NIL; + List *partially_grouped_live_children = NIL; + PathTarget *target = grouped_rel->reltarget; + + Assert(patype != PARTITIONWISE_AGGREGATE_NONE); + Assert(patype != PARTITIONWISE_AGGREGATE_PARTIAL || + partially_grouped_rel != NULL); + + /* Add paths for partitionwise aggregation/grouping. */ + for (cnt_parts = 0; cnt_parts < nparts; cnt_parts++) + { + RelOptInfo *child_input_rel = input_rel->part_rels[cnt_parts]; + PathTarget *child_target = copy_pathtarget(target); + AppendRelInfo **appinfos; + int nappinfos; + GroupPathExtraData child_extra; + RelOptInfo *child_grouped_rel; + RelOptInfo *child_partially_grouped_rel; + + /* Input child rel must have a path */ + Assert(child_input_rel->pathlist != NIL); + + /* + * Copy the given "extra" structure as is and then override the + * members specific to this child. + */ + memcpy(&child_extra, extra, sizeof(child_extra)); + + appinfos = find_appinfos_by_relids(root, child_input_rel->relids, + &nappinfos); + + child_target->exprs = (List *) + adjust_appendrel_attrs(root, + (Node *) target->exprs, + nappinfos, appinfos); + + /* Translate havingQual and targetList. */ + child_extra.havingQual = (Node *) + adjust_appendrel_attrs(root, + extra->havingQual, + nappinfos, appinfos); + child_extra.targetList = (List *) + adjust_appendrel_attrs(root, + (Node *) extra->targetList, + nappinfos, appinfos); + + /* + * extra->patype was the value computed for our parent rel; patype is + * the value for this relation. For the child, our value is its + * parent rel's value. + */ + child_extra.patype = patype; + + /* + * Create grouping relation to hold fully aggregated grouping and/or + * aggregation paths for the child. + */ + child_grouped_rel = make_grouping_rel(root, child_input_rel, + child_target, + extra->target_parallel_safe, + child_extra.havingQual); + + /* Ignore empty children. They contribute nothing. */ + if (IS_DUMMY_REL(child_input_rel)) + { + mark_dummy_rel(child_grouped_rel); + + continue; + } + + /* Create grouping paths for this child relation. */ + create_ordinary_grouping_paths(root, child_input_rel, + child_grouped_rel, + agg_costs, gd, &child_extra, + &child_partially_grouped_rel); + + if (child_partially_grouped_rel) + { + partially_grouped_live_children = + lappend(partially_grouped_live_children, + child_partially_grouped_rel); + } + + if (patype == PARTITIONWISE_AGGREGATE_FULL) + { + set_cheapest(child_grouped_rel); + grouped_live_children = lappend(grouped_live_children, + child_grouped_rel); + } + + pfree(appinfos); + } + + /* + * All children can't be dummy at this point. If they are, then the parent + * too marked as dummy. + */ + Assert(grouped_live_children != NIL || + partially_grouped_live_children != NIL); + + /* + * Try to create append paths for partially grouped children. For full + * partitionwise aggregation, we might have paths in the partial_pathlist + * if parallel aggregation is possible. For partial partitionwise + * aggregation, we may have paths in both pathlist and partial_pathlist. + */ + if (partially_grouped_rel) + { + add_paths_to_append_rel(root, partially_grouped_rel, + partially_grouped_live_children); + + /* + * We need call set_cheapest, since the finalization step will use the + * cheapest path from the rel. + */ + if (partially_grouped_rel->pathlist) + set_cheapest(partially_grouped_rel); + } + + /* If possible, create append paths for fully grouped children. */ + if (patype == PARTITIONWISE_AGGREGATE_FULL) + add_paths_to_append_rel(root, grouped_rel, grouped_live_children); +} + +/* + * group_by_has_partkey + * + * Returns true, if all the partition keys of the given relation are part of + * the GROUP BY clauses, false otherwise. + */ +static bool +group_by_has_partkey(RelOptInfo *input_rel, + List *targetList, + List *groupClause) +{ + List *groupexprs = get_sortgrouplist_exprs(groupClause, targetList); + int cnt = 0; + int partnatts; + + /* Input relation should be partitioned. */ + Assert(input_rel->part_scheme); + + /* Rule out early, if there are no partition keys present. */ + if (!input_rel->partexprs) + return false; + + partnatts = input_rel->part_scheme->partnatts; + + for (cnt = 0; cnt < partnatts; cnt++) + { + List *partexprs = input_rel->partexprs[cnt]; + ListCell *lc; + bool found = false; + + foreach(lc, partexprs) + { + Expr *partexpr = lfirst(lc); + + if (list_member(groupexprs, partexpr)) + { + found = true; + break; + } + } + + /* + * If none of the partition key expressions match with any of the + * GROUP BY expression, return false. + */ + if (!found) + return false; + } + + return true; +} + + +/* + * For a given input path, consider the possible ways of doing grouping sets on + * it, by combinations of hashing and sorting. This can be called multiple + * times, so it's important that it not scribble on input. No result is + * returned, but any generated paths are added to grouped_rel. + */ +static void +consider_groupingsets_paths(PlannerInfo *root, + RelOptInfo *grouped_rel, + Path *path, + bool is_sorted, + bool can_hash, + grouping_sets_data *gd, + const AggClauseCosts *agg_costs, + double dNumGroups) +{ + Query *parse = root->parse; + + /* + * If we're not being offered sorted input, then only consider plans that + * can be done entirely by hashing. + * + * We can hash everything if it looks like it'll fit in work_mem. But if + * the input is actually sorted despite not being advertised as such, we + * prefer to make use of that in order to use less memory. + * + * If none of the grouping sets are sortable, then ignore the work_mem + * limit and generate a path anyway, since otherwise we'll just fail. + */ + if (!is_sorted) + { + List *new_rollups = NIL; + RollupData *unhashed_rollup = NULL; + List *sets_data; + List *empty_sets_data = NIL; + List *empty_sets = NIL; + ListCell *lc; + ListCell *l_start = list_head(gd->rollups); + AggStrategy strat = AGG_HASHED; + Size hashsize; + double exclude_groups = 0.0; + + Assert(can_hash); + + /* + * If the input is coincidentally sorted usefully (which can happen + * even if is_sorted is false, since that only means that our caller + * has set up the sorting for us), then save some hashtable space by + * making use of that. But we need to watch out for degenerate cases: + * + * 1) If there are any empty grouping sets, then group_pathkeys might + * be NIL if all non-empty grouping sets are unsortable. In this case, + * there will be a rollup containing only empty groups, and the + * pathkeys_contained_in test is vacuously true; this is ok. + * + * XXX: the above relies on the fact that group_pathkeys is generated + * from the first rollup. If we add the ability to consider multiple + * sort orders for grouping input, this assumption might fail. + * + * 2) If there are no empty sets and only unsortable sets, then the + * rollups list will be empty (and thus l_start == NULL), and + * group_pathkeys will be NIL; we must ensure that the vacuously-true + * pathkeys_contain_in test doesn't cause us to crash. + */ + if (l_start != NULL && + pathkeys_contained_in(root->group_pathkeys, path->pathkeys)) + { + unhashed_rollup = lfirst_node(RollupData, l_start); + exclude_groups = unhashed_rollup->numGroups; + l_start = lnext(l_start); + } + + hashsize = estimate_hashagg_tablesize(path, + agg_costs, + dNumGroups - exclude_groups); + + /* + * gd->rollups is empty if we have only unsortable columns to work + * with. Override work_mem in that case; otherwise, we'll rely on the + * sorted-input case to generate usable mixed paths. + */ + if (hashsize > work_mem * 1024L && gd->rollups) + return; /* nope, won't fit */ + + /* + * We need to burst the existing rollups list into individual grouping + * sets and recompute a groupClause for each set. + */ + sets_data = list_copy(gd->unsortable_sets); + + for_each_cell(lc, l_start) + { + RollupData *rollup = lfirst_node(RollupData, lc); + + /* + * If we find an unhashable rollup that's not been skipped by the + * "actually sorted" check above, we can't cope; we'd need sorted + * input (with a different sort order) but we can't get that here. + * So bail out; we'll get a valid path from the is_sorted case + * instead. + * + * The mere presence of empty grouping sets doesn't make a rollup + * unhashable (see preprocess_grouping_sets), we handle those + * specially below. + */ + if (!rollup->hashable) + return; + else + sets_data = list_concat(sets_data, list_copy(rollup->gsets_data)); + } + foreach(lc, sets_data) + { + GroupingSetData *gs = lfirst_node(GroupingSetData, lc); + List *gset = gs->set; + RollupData *rollup; + + if (gset == NIL) + { + /* Empty grouping sets can't be hashed. */ + empty_sets_data = lappend(empty_sets_data, gs); + empty_sets = lappend(empty_sets, NIL); + } + else + { + rollup = makeNode(RollupData); + + rollup->groupClause = preprocess_groupclause(root, gset); + rollup->gsets_data = list_make1(gs); + rollup->gsets = remap_to_groupclause_idx(rollup->groupClause, + rollup->gsets_data, + gd->tleref_to_colnum_map); + rollup->numGroups = gs->numGroups; + rollup->hashable = true; + rollup->is_hashed = true; + new_rollups = lappend(new_rollups, rollup); + } + } + + /* + * If we didn't find anything nonempty to hash, then bail. We'll + * generate a path from the is_sorted case. + */ + if (new_rollups == NIL) + return; + + /* + * If there were empty grouping sets they should have been in the + * first rollup. + */ + Assert(!unhashed_rollup || !empty_sets); + + if (unhashed_rollup) + { + new_rollups = lappend(new_rollups, unhashed_rollup); + strat = AGG_MIXED; + } + else if (empty_sets) + { + RollupData *rollup = makeNode(RollupData); + + rollup->groupClause = NIL; + rollup->gsets_data = empty_sets_data; + rollup->gsets = empty_sets; + rollup->numGroups = list_length(empty_sets); + rollup->hashable = false; + rollup->is_hashed = false; + new_rollups = lappend(new_rollups, rollup); + strat = AGG_MIXED; + } + + add_path(grouped_rel, (Path *) + create_groupingsets_path(root, + grouped_rel, + path, + (List *) parse->havingQual, + strat, + new_rollups, + agg_costs, + dNumGroups)); + return; + } + + /* + * If we have sorted input but nothing we can do with it, bail. + */ + if (list_length(gd->rollups) == 0) + return; + + /* + * Given sorted input, we try and make two paths: one sorted and one mixed + * sort/hash. (We need to try both because hashagg might be disabled, or + * some columns might not be sortable.) + * + * can_hash is passed in as false if some obstacle elsewhere (such as + * ordered aggs) means that we shouldn't consider hashing at all. + */ + if (can_hash && gd->any_hashable) + { + List *rollups = NIL; + List *hash_sets = list_copy(gd->unsortable_sets); + double availspace = (work_mem * 1024.0); + ListCell *lc; + + /* + * Account first for space needed for groups we can't sort at all. + */ + availspace -= (double) estimate_hashagg_tablesize(path, + agg_costs, + gd->dNumHashGroups); + + if (availspace > 0 && list_length(gd->rollups) > 1) + { + double scale; + int num_rollups = list_length(gd->rollups); + int k_capacity; + int *k_weights = palloc(num_rollups * sizeof(int)); + Bitmapset *hash_items = NULL; + int i; + + /* + * We treat this as a knapsack problem: the knapsack capacity + * represents work_mem, the item weights are the estimated memory + * usage of the hashtables needed to implement a single rollup, + * and we really ought to use the cost saving as the item value; + * however, currently the costs assigned to sort nodes don't + * reflect the comparison costs well, and so we treat all items as + * of equal value (each rollup we hash instead saves us one sort). + * + * To use the discrete knapsack, we need to scale the values to a + * reasonably small bounded range. We choose to allow a 5% error + * margin; we have no more than 4096 rollups in the worst possible + * case, which with a 5% error margin will require a bit over 42MB + * of workspace. (Anyone wanting to plan queries that complex had + * better have the memory for it. In more reasonable cases, with + * no more than a couple of dozen rollups, the memory usage will + * be negligible.) + * + * k_capacity is naturally bounded, but we clamp the values for + * scale and weight (below) to avoid overflows or underflows (or + * uselessly trying to use a scale factor less than 1 byte). + */ + scale = Max(availspace / (20.0 * num_rollups), 1.0); + k_capacity = (int) floor(availspace / scale); + + /* + * We leave the first rollup out of consideration since it's the + * one that matches the input sort order. We assign indexes "i" + * to only those entries considered for hashing; the second loop, + * below, must use the same condition. + */ + i = 0; + for_each_cell(lc, lnext(list_head(gd->rollups))) + { + RollupData *rollup = lfirst_node(RollupData, lc); + + if (rollup->hashable) + { + double sz = estimate_hashagg_tablesize(path, + agg_costs, + rollup->numGroups); + + /* + * If sz is enormous, but work_mem (and hence scale) is + * small, avoid integer overflow here. + */ + k_weights[i] = (int) Min(floor(sz / scale), + k_capacity + 1.0); + ++i; + } + } + + /* + * Apply knapsack algorithm; compute the set of items which + * maximizes the value stored (in this case the number of sorts + * saved) while keeping the total size (approximately) within + * capacity. + */ + if (i > 0) + hash_items = DiscreteKnapsack(k_capacity, i, k_weights, NULL); + + if (!bms_is_empty(hash_items)) + { + rollups = list_make1(linitial(gd->rollups)); + + i = 0; + for_each_cell(lc, lnext(list_head(gd->rollups))) + { + RollupData *rollup = lfirst_node(RollupData, lc); + + if (rollup->hashable) + { + if (bms_is_member(i, hash_items)) + hash_sets = list_concat(hash_sets, + list_copy(rollup->gsets_data)); + else + rollups = lappend(rollups, rollup); + ++i; + } + else + rollups = lappend(rollups, rollup); + } + } + } + + if (!rollups && hash_sets) + rollups = list_copy(gd->rollups); + + foreach(lc, hash_sets) + { + GroupingSetData *gs = lfirst_node(GroupingSetData, lc); + RollupData *rollup = makeNode(RollupData); + + Assert(gs->set != NIL); + + rollup->groupClause = preprocess_groupclause(root, gs->set); + rollup->gsets_data = list_make1(gs); + rollup->gsets = remap_to_groupclause_idx(rollup->groupClause, + rollup->gsets_data, + gd->tleref_to_colnum_map); + rollup->numGroups = gs->numGroups; + rollup->hashable = true; + rollup->is_hashed = true; + rollups = lcons(rollup, rollups); + } + + if (rollups) + { + add_path(grouped_rel, (Path *) + create_groupingsets_path(root, + grouped_rel, + path, + (List *) parse->havingQual, + AGG_MIXED, + rollups, + agg_costs, + dNumGroups)); + } + } + + /* + * Now try the simple sorted case. + */ + if (!gd->unsortable_sets) + add_path(grouped_rel, (Path *) + create_groupingsets_path(root, + grouped_rel, + path, + (List *) parse->havingQual, + AGG_SORTED, + gd->rollups, + agg_costs, + dNumGroups)); +} + + +/* + * Given a groupclause and a list of GroupingSetData, return equivalent sets + * (without annotation) mapped to indexes into the given groupclause. + */ +List * +remap_to_groupclause_idx(List *groupClause, + List *gsets, + int *tleref_to_colnum_map) +{ + int ref = 0; + List *result = NIL; + ListCell *lc; + + foreach(lc, groupClause) + { + SortGroupClause *gc = lfirst_node(SortGroupClause, lc); + + tleref_to_colnum_map[gc->tleSortGroupRef] = ref++; + } + + foreach(lc, gsets) + { + List *set = NIL; + ListCell *lc2; + GroupingSetData *gs = lfirst_node(GroupingSetData, lc); + + foreach(lc2, gs->set) + { + set = lappend_int(set, tleref_to_colnum_map[lfirst_int(lc2)]); + } + + result = lappend(result, set); + } + + return result; +} diff --git a/src/backend/optimizer/plan/Makefile b/src/backend/optimizer/plan/Makefile index 88a9f7ff8c..e3c96b704e 100644 --- a/src/backend/optimizer/plan/Makefile +++ b/src/backend/optimizer/plan/Makefile @@ -12,7 +12,7 @@ subdir = src/backend/optimizer/plan top_builddir = ../../../.. include $(top_builddir)/src/Makefile.global -OBJS = analyzejoins.o createplan.o initsplan.o planagg.o planmain.o planner.o \ - setrefs.o subselect.o +OBJS = analyzejoins.o createplan.o initsplan.o planagg.o planmain.o \ + planner.o setrefs.o subselect.o include $(top_srcdir)/src/backend/common.mk diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c index e73007f3ba..0d31eded37 100644 --- a/src/backend/optimizer/plan/planner.c +++ b/src/backend/optimizer/plan/planner.c @@ -28,10 +28,9 @@ #include "executor/executor.h" #include "executor/nodeAgg.h" #include "foreign/fdwapi.h" +#include "lib/bipartite_match.h" #include "miscadmin.h" #include "jit/jit.h" -#include "lib/bipartite_match.h" -#include "lib/knapsack.h" #include "nodes/makefuncs.h" #include "nodes/nodeFuncs.h" #ifdef OPTIMIZER_DEBUG @@ -94,22 +93,6 @@ typedef struct List *groupClause; /* overrides parse->groupClause */ } standard_qp_extra; -/* - * Data specific to grouping sets - */ - -typedef struct -{ - List *rollups; - List *hash_sets_idx; - double dNumHashGroups; - bool any_hashable; - Bitmapset *unsortable_refs; - Bitmapset *unhashable_refs; - List *unsortable_sets; - int *tleref_to_colnum_map; -} grouping_sets_data; - /* Local functions */ static Node *preprocess_expression(PlannerInfo *root, Node *expr, int kind); static void preprocess_qual_conditions(PlannerInfo *root, Node *jtnode); @@ -117,53 +100,12 @@ static void inheritance_planner(PlannerInfo *root); static void grouping_planner(PlannerInfo *root, bool inheritance_update, double tuple_fraction); static void compute_pathkeys(PlannerInfo *root, List *tlist, List *activeWindows, List *groupClause); -static grouping_sets_data *preprocess_grouping_sets(PlannerInfo *root); -static List *remap_to_groupclause_idx(List *groupClause, List *gsets, - int *tleref_to_colnum_map); static void preprocess_rowmarks(PlannerInfo *root); static double preprocess_limit(PlannerInfo *root, double tuple_fraction, int64 *offset_est, int64 *count_est); static bool limit_needed(Query *parse); static void remove_useless_groupby_columns(PlannerInfo *root); -static List *preprocess_groupclause(PlannerInfo *root, List *force); -static List *extract_rollup_sets(List *groupingSets); -static List *reorder_grouping_sets(List *groupingSets, List *sortclause); -static double get_number_of_groups(PlannerInfo *root, - double path_rows, - grouping_sets_data *gd, - List *target_list); -static Size estimate_hashagg_tablesize(Path *path, - const AggClauseCosts *agg_costs, - double dNumGroups); -static RelOptInfo *create_grouping_paths(PlannerInfo *root, - RelOptInfo *input_rel, - PathTarget *target, - bool target_parallel_safe, - const AggClauseCosts *agg_costs, - grouping_sets_data *gd); -static bool is_degenerate_grouping(PlannerInfo *root); -static void create_degenerate_grouping_paths(PlannerInfo *root, - RelOptInfo *input_rel, - RelOptInfo *grouped_rel); -static RelOptInfo *make_grouping_rel(PlannerInfo *root, RelOptInfo *input_rel, - PathTarget *target, bool target_parallel_safe, - Node *havingQual); -static void create_ordinary_grouping_paths(PlannerInfo *root, - RelOptInfo *input_rel, - RelOptInfo *grouped_rel, - const AggClauseCosts *agg_costs, - grouping_sets_data *gd, - GroupPathExtraData *extra, - RelOptInfo **partially_grouped_rel_p); -static void consider_groupingsets_paths(PlannerInfo *root, - RelOptInfo *grouped_rel, - Path *path, - bool is_sorted, - bool can_hash, - grouping_sets_data *gd, - const AggClauseCosts *agg_costs, - double dNumGroups); static RelOptInfo *create_window_paths(PlannerInfo *root, RelOptInfo *input_rel, PathTarget *input_target, @@ -189,9 +131,6 @@ static RelOptInfo *create_ordered_paths(PlannerInfo *root, double limit_tuples); static PathTarget *make_group_input_target(PlannerInfo *root, PathTarget *final_target); -static PathTarget *make_partial_grouping_target(PlannerInfo *root, - PathTarget *grouping_target, - Node *havingQual); static List *postprocess_setop_tlist(List *new_tlist, List *orig_tlist); static List *select_active_windows(PlannerInfo *root, WindowFuncLists *wflists); static PathTarget *make_window_input_target(PlannerInfo *root, @@ -204,39 +143,14 @@ static PathTarget *make_sort_input_target(PlannerInfo *root, bool *have_postponed_srfs); static void adjust_paths_for_srfs(PlannerInfo *root, RelOptInfo *rel, List *targets, List *targets_contain_srfs); -static void add_paths_to_grouping_rel(PlannerInfo *root, RelOptInfo *input_rel, - RelOptInfo *grouped_rel, - RelOptInfo *partially_grouped_rel, - const AggClauseCosts *agg_costs, - grouping_sets_data *gd, - double dNumGroups, - GroupPathExtraData *extra); -static RelOptInfo *create_partial_grouping_paths(PlannerInfo *root, - RelOptInfo *grouped_rel, - RelOptInfo *input_rel, - grouping_sets_data *gd, - GroupPathExtraData *extra, - bool force_rel_creation); -static void gather_grouping_paths(PlannerInfo *root, RelOptInfo *rel); -static bool can_partial_agg(PlannerInfo *root, - const AggClauseCosts *agg_costs); static void apply_scanjoin_target_to_paths(PlannerInfo *root, RelOptInfo *rel, List *scanjoin_targets, List *scanjoin_targets_contain_srfs, bool scanjoin_target_parallel_safe, bool tlist_same_exprs); -static void create_partitionwise_grouping_paths(PlannerInfo *root, - RelOptInfo *input_rel, - RelOptInfo *grouped_rel, - RelOptInfo *partially_grouped_rel, - const AggClauseCosts *agg_costs, - grouping_sets_data *gd, - PartitionwiseAggregateType patype, - GroupPathExtraData *extra); -static bool group_by_has_partkey(RelOptInfo *input_rel, - List *targetList, - List *groupClause); +static List *extract_rollup_sets(List *groupingSets); +static List *reorder_grouping_sets(List *groupingSets, List *sortclause); /***************************************************************************** @@ -2252,13 +2166,121 @@ grouping_planner(PlannerInfo *root, bool inheritance_update, /* Note: currently, we leave it to callers to do set_cheapest() */ } + + + +/* + * preprocess_groupclause - do preparatory work on GROUP BY clause + * + * The idea here is to adjust the ordering of the GROUP BY elements + * (which in itself is semantically insignificant) to match ORDER BY, + * thereby allowing a single sort operation to both implement the ORDER BY + * requirement and set up for a Unique step that implements GROUP BY. + * + * In principle it might be interesting to consider other orderings of the + * GROUP BY elements, which could match the sort ordering of other + * possible plans (eg an indexscan) and thereby reduce cost. We don't + * bother with that, though. Hashed grouping will frequently win anyway. + * + * Note: we need no comparable processing of the distinctClause because + * the parser already enforced that that matches ORDER BY. + * + * For grouping sets, the order of items is instead forced to agree with that + * of the grouping set (and items not in the grouping set are skipped). The + * work of sorting the order of grouping set elements to match the ORDER BY if + * possible is done elsewhere. + */ +List * +preprocess_groupclause(PlannerInfo *root, List *force) +{ + Query *parse = root->parse; + List *new_groupclause = NIL; + bool partial_match; + ListCell *sl; + ListCell *gl; + + /* For grouping sets, we need to force the ordering */ + if (force) + { + foreach(sl, force) + { + Index ref = lfirst_int(sl); + SortGroupClause *cl = get_sortgroupref_clause(ref, parse->groupClause); + + new_groupclause = lappend(new_groupclause, cl); + } + + return new_groupclause; + } + + /* If no ORDER BY, nothing useful to do here */ + if (parse->sortClause == NIL) + return parse->groupClause; + + /* + * Scan the ORDER BY clause and construct a list of matching GROUP BY + * items, but only as far as we can make a matching prefix. + * + * This code assumes that the sortClause contains no duplicate items. + */ + foreach(sl, parse->sortClause) + { + SortGroupClause *sc = lfirst_node(SortGroupClause, sl); + + foreach(gl, parse->groupClause) + { + SortGroupClause *gc = lfirst_node(SortGroupClause, gl); + + if (equal(gc, sc)) + { + new_groupclause = lappend(new_groupclause, gc); + break; + } + } + if (gl == NULL) + break; /* no match, so stop scanning */ + } + + /* Did we match all of the ORDER BY list, or just some of it? */ + partial_match = (sl != NULL); + + /* If no match at all, no point in reordering GROUP BY */ + if (new_groupclause == NIL) + return parse->groupClause; + + /* + * Add any remaining GROUP BY items to the new list, but only if we were + * able to make a complete match. In other words, we only rearrange the + * GROUP BY list if the result is that one list is a prefix of the other + * --- otherwise there's no possibility of a common sort. Also, give up + * if there are any non-sortable GROUP BY items, since then there's no + * hope anyway. + */ + foreach(gl, parse->groupClause) + { + SortGroupClause *gc = lfirst_node(SortGroupClause, gl); + + if (list_member_ptr(new_groupclause, gc)) + continue; /* it matched an ORDER BY item */ + if (partial_match) + return parse->groupClause; /* give up, no common sort possible */ + if (!OidIsValid(gc->sortop)) + return parse->groupClause; /* give up, GROUP BY can't be sorted */ + new_groupclause = lappend(new_groupclause, gc); + } + + /* Success --- install the rearranged GROUP BY list */ + Assert(list_length(parse->groupClause) == list_length(new_groupclause)); + return new_groupclause; +} + /* * Do preprocessing for groupingSets clause and related data. This handles the * preliminary steps of expanding the grouping sets, organizing them into lists * of rollups, and preparing annotations which will later be filled in with * size estimates. */ -static grouping_sets_data * +grouping_sets_data * preprocess_grouping_sets(PlannerInfo *root) { Query *parse = root->parse; @@ -2430,65 +2452,307 @@ preprocess_grouping_sets(PlannerInfo *root) } /* - * Given a groupclause and a list of GroupingSetData, return equivalent sets - * (without annotation) mapped to indexes into the given groupclause. + * Extract lists of grouping sets that can be implemented using a single + * rollup-type aggregate pass each. Returns a list of lists of grouping sets. + * + * Input must be sorted with smallest sets first. Result has each sublist + * sorted with smallest sets first. + * + * We want to produce the absolute minimum possible number of lists here to + * avoid excess sorts. Fortunately, there is an algorithm for this; the problem + * of finding the minimal partition of a partially-ordered set into chains + * (which is what we need, taking the list of grouping sets as a poset ordered + * by set inclusion) can be mapped to the problem of finding the maximum + * cardinality matching on a bipartite graph, which is solvable in polynomial + * time with a worst case of no worse than O(n^2.5) and usually much + * better. Since our N is at most 4096, we don't need to consider fallbacks to + * heuristic or approximate methods. (Planning time for a 12-d cube is under + * half a second on my modest system even with optimization off and assertions + * on.) */ static List * -remap_to_groupclause_idx(List *groupClause, - List *gsets, - int *tleref_to_colnum_map) +extract_rollup_sets(List *groupingSets) { - int ref = 0; + int num_sets_raw = list_length(groupingSets); + int num_empty = 0; + int num_sets = 0; /* distinct sets */ + int num_chains = 0; List *result = NIL; + List **results; + List **orig_sets; + Bitmapset **set_masks; + int *chains; + short **adjacency; + short *adjacency_buf; + BipartiteMatchState *state; + int i; + int j; + int j_size; + ListCell *lc1 = list_head(groupingSets); ListCell *lc; - foreach(lc, groupClause) + /* + * Start by stripping out empty sets. The algorithm doesn't require this, + * but the planner currently needs all empty sets to be returned in the + * first list, so we strip them here and add them back after. + */ + while (lc1 && lfirst(lc1) == NIL) { - SortGroupClause *gc = lfirst_node(SortGroupClause, lc); - - tleref_to_colnum_map[gc->tleSortGroupRef] = ref++; + ++num_empty; + lc1 = lnext(lc1); } - foreach(lc, gsets) + /* bail out now if it turns out that all we had were empty sets. */ + if (!lc1) + return list_make1(groupingSets); + + /*---------- + * We don't strictly need to remove duplicate sets here, but if we don't, + * they tend to become scattered through the result, which is a bit + * confusing (and irritating if we ever decide to optimize them out). + * So we remove them here and add them back after. + * + * For each non-duplicate set, we fill in the following: + * + * orig_sets[i] = list of the original set lists + * set_masks[i] = bitmapset for testing inclusion + * adjacency[i] = array [n, v1, v2, ... vn] of adjacency indices + * + * chains[i] will be the result group this set is assigned to. + * + * We index all of these from 1 rather than 0 because it is convenient + * to leave 0 free for the NIL node in the graph algorithm. + *---------- + */ + orig_sets = palloc0((num_sets_raw + 1) * sizeof(List *)); + set_masks = palloc0((num_sets_raw + 1) * sizeof(Bitmapset *)); + adjacency = palloc0((num_sets_raw + 1) * sizeof(short *)); + adjacency_buf = palloc((num_sets_raw + 1) * sizeof(short)); + + j_size = 0; + j = 0; + i = 1; + + for_each_cell(lc, lc1) { - List *set = NIL; + List *candidate = (List *) lfirst(lc); + Bitmapset *candidate_set = NULL; ListCell *lc2; - GroupingSetData *gs = lfirst_node(GroupingSetData, lc); + int dup_of = 0; - foreach(lc2, gs->set) + foreach(lc2, candidate) { - set = lappend_int(set, tleref_to_colnum_map[lfirst_int(lc2)]); + candidate_set = bms_add_member(candidate_set, lfirst_int(lc2)); } - result = lappend(result, set); - } + /* we can only be a dup if we're the same length as a previous set */ + if (j_size == list_length(candidate)) + { + int k; - return result; -} + for (k = j; k < i; ++k) + { + if (bms_equal(set_masks[k], candidate_set)) + { + dup_of = k; + break; + } + } + } + else if (j_size < list_length(candidate)) + { + j_size = list_length(candidate); + j = i; + } + if (dup_of > 0) + { + orig_sets[dup_of] = lappend(orig_sets[dup_of], candidate); + bms_free(candidate_set); + } + else + { + int k; + int n_adj = 0; + orig_sets[i] = list_make1(candidate); + set_masks[i] = candidate_set; -/* - * Detect whether a plan node is a "dummy" plan created when a relation - * is deemed not to need scanning due to constraint exclusion. - * - * Currently, such dummy plans are Result nodes with constant FALSE - * filter quals (see set_dummy_rel_pathlist and create_append_plan). - * - * XXX this probably ought to be somewhere else, but not clear where. - */ -bool -is_dummy_plan(Plan *plan) -{ - if (IsA(plan, Result)) - { - List *rcqual = (List *) ((Result *) plan)->resconstantqual; + /* fill in adjacency list; no need to compare equal-size sets */ - if (list_length(rcqual) == 1) - { - Const *constqual = (Const *) linitial(rcqual); + for (k = j - 1; k > 0; --k) + { + if (bms_is_subset(set_masks[k], candidate_set)) + adjacency_buf[++n_adj] = k; + } - if (constqual && IsA(constqual, Const)) + if (n_adj > 0) + { + adjacency_buf[0] = n_adj; + adjacency[i] = palloc((n_adj + 1) * sizeof(short)); + memcpy(adjacency[i], adjacency_buf, (n_adj + 1) * sizeof(short)); + } + else + adjacency[i] = NULL; + + ++i; + } + } + + num_sets = i - 1; + + /* + * Apply the graph matching algorithm to do the work. + */ + state = BipartiteMatch(num_sets, num_sets, adjacency); + + /* + * Now, the state->pair* fields have the info we need to assign sets to + * chains. Two sets (u,v) belong to the same chain if pair_uv[u] = v or + * pair_vu[v] = u (both will be true, but we check both so that we can do + * it in one pass) + */ + chains = palloc0((num_sets + 1) * sizeof(int)); + + for (i = 1; i <= num_sets; ++i) + { + int u = state->pair_vu[i]; + int v = state->pair_uv[i]; + + if (u > 0 && u < i) + chains[i] = chains[u]; + else if (v > 0 && v < i) + chains[i] = chains[v]; + else + chains[i] = ++num_chains; + } + + /* build result lists. */ + results = palloc0((num_chains + 1) * sizeof(List *)); + + for (i = 1; i <= num_sets; ++i) + { + int c = chains[i]; + + Assert(c > 0); + + results[c] = list_concat(results[c], orig_sets[i]); + } + + /* push any empty sets back on the first list. */ + while (num_empty-- > 0) + results[1] = lcons(NIL, results[1]); + + /* make result list */ + for (i = 1; i <= num_chains; ++i) + result = lappend(result, results[i]); + + /* + * Free all the things. + * + * (This is over-fussy for small sets but for large sets we could have + * tied up a nontrivial amount of memory.) + */ + BipartiteMatchFree(state); + pfree(results); + pfree(chains); + for (i = 1; i <= num_sets; ++i) + if (adjacency[i]) + pfree(adjacency[i]); + pfree(adjacency); + pfree(adjacency_buf); + pfree(orig_sets); + for (i = 1; i <= num_sets; ++i) + bms_free(set_masks[i]); + pfree(set_masks); + + return result; +} + +/* + * Reorder the elements of a list of grouping sets such that they have correct + * prefix relationships. Also inserts the GroupingSetData annotations. + * + * The input must be ordered with smallest sets first; the result is returned + * with largest sets first. Note that the result shares no list substructure + * with the input, so it's safe for the caller to modify it later. + * + * If we're passed in a sortclause, we follow its order of columns to the + * extent possible, to minimize the chance that we add unnecessary sorts. + * (We're trying here to ensure that GROUPING SETS ((a,b,c),(c)) ORDER BY c,b,a + * gets implemented in one pass.) + */ +static List * +reorder_grouping_sets(List *groupingsets, List *sortclause) +{ + ListCell *lc; + ListCell *lc2; + List *previous = NIL; + List *result = NIL; + + foreach(lc, groupingsets) + { + List *candidate = (List *) lfirst(lc); + List *new_elems = list_difference_int(candidate, previous); + GroupingSetData *gs = makeNode(GroupingSetData); + + if (list_length(new_elems) > 0) + { + while (list_length(sortclause) > list_length(previous)) + { + SortGroupClause *sc = list_nth(sortclause, list_length(previous)); + int ref = sc->tleSortGroupRef; + + if (list_member_int(new_elems, ref)) + { + previous = lappend_int(previous, ref); + new_elems = list_delete_int(new_elems, ref); + } + else + { + /* diverged from the sortclause; give up on it */ + sortclause = NIL; + break; + } + } + + foreach(lc2, new_elems) + { + previous = lappend_int(previous, lfirst_int(lc2)); + } + } + + gs->set = list_copy(previous); + result = lcons(gs, result); + list_free(new_elems); + } + + list_free(previous); + + return result; +} + +/* + * Detect whether a plan node is a "dummy" plan created when a relation + * is deemed not to need scanning due to constraint exclusion. + * + * Currently, such dummy plans are Result nodes with constant FALSE + * filter quals (see set_dummy_rel_pathlist and create_append_plan). + * + * XXX this probably ought to be somewhere else, but not clear where. + */ +bool +is_dummy_plan(Plan *plan) +{ + if (IsA(plan, Result)) + { + List *rcqual = (List *) ((Result *) plan)->resconstantqual; + + if (list_length(rcqual) == 1) + { + Const *constqual = (Const *) linitial(rcqual); + + if (constqual && IsA(constqual, Const)) { if (!constqual->constisnull && !DatumGetBool(constqual->constvalue)) @@ -3058,3708 +3322,1699 @@ remove_useless_groupby_columns(PlannerInfo *root) } /* - * preprocess_groupclause - do preparatory work on GROUP BY clause - * - * The idea here is to adjust the ordering of the GROUP BY elements - * (which in itself is semantically insignificant) to match ORDER BY, - * thereby allowing a single sort operation to both implement the ORDER BY - * requirement and set up for a Unique step that implements GROUP BY. - * - * In principle it might be interesting to consider other orderings of the - * GROUP BY elements, which could match the sort ordering of other - * possible plans (eg an indexscan) and thereby reduce cost. We don't - * bother with that, though. Hashed grouping will frequently win anyway. - * - * Note: we need no comparable processing of the distinctClause because - * the parser already enforced that that matches ORDER BY. - * - * For grouping sets, the order of items is instead forced to agree with that - * of the grouping set (and items not in the grouping set are skipped). The - * work of sorting the order of grouping set elements to match the ORDER BY if - * possible is done elsewhere. + * Compute query_pathkeys and other pathkeys, to tell query_planner() which + * orderings would be useful for the later planner stages. */ -static List * -preprocess_groupclause(PlannerInfo *root, List *force) +static void +compute_pathkeys(PlannerInfo *root, List *tlist, List *activeWindows, List *groupClause) { Query *parse = root->parse; - List *new_groupclause = NIL; - bool partial_match; - ListCell *sl; - ListCell *gl; - /* For grouping sets, we need to force the ordering */ - if (force) - { - foreach(sl, force) - { - Index ref = lfirst_int(sl); - SortGroupClause *cl = get_sortgroupref_clause(ref, parse->groupClause); + /* + * Calculate pathkeys that represent grouping/ordering requirements. The + * sortClause is certainly sort-able, but GROUP BY and DISTINCT might not + * be, in which case we just leave their pathkeys empty. + */ + if (groupClause && grouping_is_sortable(groupClause)) + root->group_pathkeys = + make_pathkeys_for_sortclauses(root, + groupClause, + tlist); + else + root->group_pathkeys = NIL; - new_groupclause = lappend(new_groupclause, cl); - } + /* We consider only the first (bottom) window in pathkeys logic */ + if (activeWindows != NIL) + { + WindowClause *wc = linitial_node(WindowClause, activeWindows); - return new_groupclause; + root->window_pathkeys = make_pathkeys_for_window(root, + wc, + tlist); } + else + root->window_pathkeys = NIL; - /* If no ORDER BY, nothing useful to do here */ - if (parse->sortClause == NIL) - return parse->groupClause; + if (parse->distinctClause && + grouping_is_sortable(parse->distinctClause)) + root->distinct_pathkeys = + make_pathkeys_for_sortclauses(root, + parse->distinctClause, + tlist); + else + root->distinct_pathkeys = NIL; + + root->sort_pathkeys = + make_pathkeys_for_sortclauses(root, + parse->sortClause, + tlist); /* - * Scan the ORDER BY clause and construct a list of matching GROUP BY - * items, but only as far as we can make a matching prefix. + * Figure out whether we want a sorted result from query_planner. * - * This code assumes that the sortClause contains no duplicate items. - */ - foreach(sl, parse->sortClause) - { - SortGroupClause *sc = lfirst_node(SortGroupClause, sl); - - foreach(gl, parse->groupClause) - { - SortGroupClause *gc = lfirst_node(SortGroupClause, gl); - - if (equal(gc, sc)) - { - new_groupclause = lappend(new_groupclause, gc); - break; - } - } - if (gl == NULL) - break; /* no match, so stop scanning */ - } - - /* Did we match all of the ORDER BY list, or just some of it? */ - partial_match = (sl != NULL); - - /* If no match at all, no point in reordering GROUP BY */ - if (new_groupclause == NIL) - return parse->groupClause; - - /* - * Add any remaining GROUP BY items to the new list, but only if we were - * able to make a complete match. In other words, we only rearrange the - * GROUP BY list if the result is that one list is a prefix of the other - * --- otherwise there's no possibility of a common sort. Also, give up - * if there are any non-sortable GROUP BY items, since then there's no - * hope anyway. - */ - foreach(gl, parse->groupClause) - { - SortGroupClause *gc = lfirst_node(SortGroupClause, gl); - - if (list_member_ptr(new_groupclause, gc)) - continue; /* it matched an ORDER BY item */ - if (partial_match) - return parse->groupClause; /* give up, no common sort possible */ - if (!OidIsValid(gc->sortop)) - return parse->groupClause; /* give up, GROUP BY can't be sorted */ - new_groupclause = lappend(new_groupclause, gc); - } - - /* Success --- install the rearranged GROUP BY list */ - Assert(list_length(parse->groupClause) == list_length(new_groupclause)); - return new_groupclause; -} - -/* - * Extract lists of grouping sets that can be implemented using a single - * rollup-type aggregate pass each. Returns a list of lists of grouping sets. - * - * Input must be sorted with smallest sets first. Result has each sublist - * sorted with smallest sets first. - * - * We want to produce the absolute minimum possible number of lists here to - * avoid excess sorts. Fortunately, there is an algorithm for this; the problem - * of finding the minimal partition of a partially-ordered set into chains - * (which is what we need, taking the list of grouping sets as a poset ordered - * by set inclusion) can be mapped to the problem of finding the maximum - * cardinality matching on a bipartite graph, which is solvable in polynomial - * time with a worst case of no worse than O(n^2.5) and usually much - * better. Since our N is at most 4096, we don't need to consider fallbacks to - * heuristic or approximate methods. (Planning time for a 12-d cube is under - * half a second on my modest system even with optimization off and assertions - * on.) - */ -static List * -extract_rollup_sets(List *groupingSets) -{ - int num_sets_raw = list_length(groupingSets); - int num_empty = 0; - int num_sets = 0; /* distinct sets */ - int num_chains = 0; - List *result = NIL; - List **results; - List **orig_sets; - Bitmapset **set_masks; - int *chains; - short **adjacency; - short *adjacency_buf; - BipartiteMatchState *state; - int i; - int j; - int j_size; - ListCell *lc1 = list_head(groupingSets); - ListCell *lc; - - /* - * Start by stripping out empty sets. The algorithm doesn't require this, - * but the planner currently needs all empty sets to be returned in the - * first list, so we strip them here and add them back after. - */ - while (lc1 && lfirst(lc1) == NIL) - { - ++num_empty; - lc1 = lnext(lc1); - } - - /* bail out now if it turns out that all we had were empty sets. */ - if (!lc1) - return list_make1(groupingSets); - - /*---------- - * We don't strictly need to remove duplicate sets here, but if we don't, - * they tend to become scattered through the result, which is a bit - * confusing (and irritating if we ever decide to optimize them out). - * So we remove them here and add them back after. - * - * For each non-duplicate set, we fill in the following: - * - * orig_sets[i] = list of the original set lists - * set_masks[i] = bitmapset for testing inclusion - * adjacency[i] = array [n, v1, v2, ... vn] of adjacency indices - * - * chains[i] will be the result group this set is assigned to. - * - * We index all of these from 1 rather than 0 because it is convenient - * to leave 0 free for the NIL node in the graph algorithm. - *---------- - */ - orig_sets = palloc0((num_sets_raw + 1) * sizeof(List *)); - set_masks = palloc0((num_sets_raw + 1) * sizeof(Bitmapset *)); - adjacency = palloc0((num_sets_raw + 1) * sizeof(short *)); - adjacency_buf = palloc((num_sets_raw + 1) * sizeof(short)); - - j_size = 0; - j = 0; - i = 1; - - for_each_cell(lc, lc1) - { - List *candidate = (List *) lfirst(lc); - Bitmapset *candidate_set = NULL; - ListCell *lc2; - int dup_of = 0; - - foreach(lc2, candidate) - { - candidate_set = bms_add_member(candidate_set, lfirst_int(lc2)); - } - - /* we can only be a dup if we're the same length as a previous set */ - if (j_size == list_length(candidate)) - { - int k; - - for (k = j; k < i; ++k) - { - if (bms_equal(set_masks[k], candidate_set)) - { - dup_of = k; - break; - } - } - } - else if (j_size < list_length(candidate)) - { - j_size = list_length(candidate); - j = i; - } - - if (dup_of > 0) - { - orig_sets[dup_of] = lappend(orig_sets[dup_of], candidate); - bms_free(candidate_set); - } - else - { - int k; - int n_adj = 0; - - orig_sets[i] = list_make1(candidate); - set_masks[i] = candidate_set; - - /* fill in adjacency list; no need to compare equal-size sets */ - - for (k = j - 1; k > 0; --k) - { - if (bms_is_subset(set_masks[k], candidate_set)) - adjacency_buf[++n_adj] = k; - } - - if (n_adj > 0) - { - adjacency_buf[0] = n_adj; - adjacency[i] = palloc((n_adj + 1) * sizeof(short)); - memcpy(adjacency[i], adjacency_buf, (n_adj + 1) * sizeof(short)); - } - else - adjacency[i] = NULL; - - ++i; - } - } - - num_sets = i - 1; - - /* - * Apply the graph matching algorithm to do the work. - */ - state = BipartiteMatch(num_sets, num_sets, adjacency); - - /* - * Now, the state->pair* fields have the info we need to assign sets to - * chains. Two sets (u,v) belong to the same chain if pair_uv[u] = v or - * pair_vu[v] = u (both will be true, but we check both so that we can do - * it in one pass) - */ - chains = palloc0((num_sets + 1) * sizeof(int)); - - for (i = 1; i <= num_sets; ++i) - { - int u = state->pair_vu[i]; - int v = state->pair_uv[i]; - - if (u > 0 && u < i) - chains[i] = chains[u]; - else if (v > 0 && v < i) - chains[i] = chains[v]; - else - chains[i] = ++num_chains; - } - - /* build result lists. */ - results = palloc0((num_chains + 1) * sizeof(List *)); - - for (i = 1; i <= num_sets; ++i) - { - int c = chains[i]; - - Assert(c > 0); - - results[c] = list_concat(results[c], orig_sets[i]); - } - - /* push any empty sets back on the first list. */ - while (num_empty-- > 0) - results[1] = lcons(NIL, results[1]); - - /* make result list */ - for (i = 1; i <= num_chains; ++i) - result = lappend(result, results[i]); - - /* - * Free all the things. - * - * (This is over-fussy for small sets but for large sets we could have - * tied up a nontrivial amount of memory.) - */ - BipartiteMatchFree(state); - pfree(results); - pfree(chains); - for (i = 1; i <= num_sets; ++i) - if (adjacency[i]) - pfree(adjacency[i]); - pfree(adjacency); - pfree(adjacency_buf); - pfree(orig_sets); - for (i = 1; i <= num_sets; ++i) - bms_free(set_masks[i]); - pfree(set_masks); - - return result; -} - -/* - * Reorder the elements of a list of grouping sets such that they have correct - * prefix relationships. Also inserts the GroupingSetData annotations. - * - * The input must be ordered with smallest sets first; the result is returned - * with largest sets first. Note that the result shares no list substructure - * with the input, so it's safe for the caller to modify it later. - * - * If we're passed in a sortclause, we follow its order of columns to the - * extent possible, to minimize the chance that we add unnecessary sorts. - * (We're trying here to ensure that GROUPING SETS ((a,b,c),(c)) ORDER BY c,b,a - * gets implemented in one pass.) - */ -static List * -reorder_grouping_sets(List *groupingsets, List *sortclause) -{ - ListCell *lc; - ListCell *lc2; - List *previous = NIL; - List *result = NIL; - - foreach(lc, groupingsets) - { - List *candidate = (List *) lfirst(lc); - List *new_elems = list_difference_int(candidate, previous); - GroupingSetData *gs = makeNode(GroupingSetData); - - if (list_length(new_elems) > 0) - { - while (list_length(sortclause) > list_length(previous)) - { - SortGroupClause *sc = list_nth(sortclause, list_length(previous)); - int ref = sc->tleSortGroupRef; - - if (list_member_int(new_elems, ref)) - { - previous = lappend_int(previous, ref); - new_elems = list_delete_int(new_elems, ref); - } - else - { - /* diverged from the sortclause; give up on it */ - sortclause = NIL; - break; - } - } - - foreach(lc2, new_elems) - { - previous = lappend_int(previous, lfirst_int(lc2)); - } - } - - gs->set = list_copy(previous); - result = lcons(gs, result); - list_free(new_elems); - } - - list_free(previous); - - return result; -} - -/* - * Compute query_pathkeys and other pathkeys, to tell query_planner() which - * orderings would be useful for the later planner stages. - */ -static void -compute_pathkeys(PlannerInfo *root, List *tlist, List *activeWindows, List *groupClause) -{ - Query *parse = root->parse; - - /* - * Calculate pathkeys that represent grouping/ordering requirements. The - * sortClause is certainly sort-able, but GROUP BY and DISTINCT might not - * be, in which case we just leave their pathkeys empty. - */ - if (groupClause && grouping_is_sortable(groupClause)) - root->group_pathkeys = - make_pathkeys_for_sortclauses(root, - groupClause, - tlist); - else - root->group_pathkeys = NIL; - - /* We consider only the first (bottom) window in pathkeys logic */ - if (activeWindows != NIL) - { - WindowClause *wc = linitial_node(WindowClause, activeWindows); - - root->window_pathkeys = make_pathkeys_for_window(root, - wc, - tlist); - } - else - root->window_pathkeys = NIL; - - if (parse->distinctClause && - grouping_is_sortable(parse->distinctClause)) - root->distinct_pathkeys = - make_pathkeys_for_sortclauses(root, - parse->distinctClause, - tlist); - else - root->distinct_pathkeys = NIL; - - root->sort_pathkeys = - make_pathkeys_for_sortclauses(root, - parse->sortClause, - tlist); - - /* - * Figure out whether we want a sorted result from query_planner. - * - * If we have a sortable GROUP BY clause, then we want a result sorted - * properly for grouping. Otherwise, if we have window functions to - * evaluate, we try to sort for the first window. Otherwise, if there's a - * sortable DISTINCT clause that's more rigorous than the ORDER BY clause, - * we try to produce output that's sufficiently well sorted for the - * DISTINCT. Otherwise, if there is an ORDER BY clause, we want to sort - * by the ORDER BY clause. - * - * Note: if we have both ORDER BY and GROUP BY, and ORDER BY is a superset - * of GROUP BY, it would be tempting to request sort by ORDER BY --- but - * that might just leave us failing to exploit an available sort order at - * all. Needs more thought. The choice for DISTINCT versus ORDER BY is - * much easier, since we know that the parser ensured that one is a - * superset of the other. - */ - if (root->group_pathkeys) - root->query_pathkeys = root->group_pathkeys; - else if (root->window_pathkeys) - root->query_pathkeys = root->window_pathkeys; - else if (list_length(root->distinct_pathkeys) > - list_length(root->sort_pathkeys)) - root->query_pathkeys = root->distinct_pathkeys; - else if (root->sort_pathkeys) - root->query_pathkeys = root->sort_pathkeys; - else - root->query_pathkeys = NIL; -} - -/* - * Estimate number of groups produced by grouping clauses (1 if not grouping) - * - * path_rows: number of output rows from scan/join step - * gd: grouping sets data including list of grouping sets and their clauses - * target_list: target list containing group clause references - * - * If doing grouping sets, we also annotate the gsets data with the estimates - * for each set and each individual rollup list, with a view to later - * determining whether some combination of them could be hashed instead. - */ -static double -get_number_of_groups(PlannerInfo *root, - double path_rows, - grouping_sets_data *gd, - List *target_list) -{ - Query *parse = root->parse; - double dNumGroups; - - if (parse->groupClause) - { - List *groupExprs; - - if (parse->groupingSets) - { - /* Add up the estimates for each grouping set */ - ListCell *lc; - ListCell *lc2; - - Assert(gd); /* keep Coverity happy */ - - dNumGroups = 0; - - foreach(lc, gd->rollups) - { - RollupData *rollup = lfirst_node(RollupData, lc); - ListCell *lc; - - groupExprs = get_sortgrouplist_exprs(rollup->groupClause, - target_list); - - rollup->numGroups = 0.0; - - forboth(lc, rollup->gsets, lc2, rollup->gsets_data) - { - List *gset = (List *) lfirst(lc); - GroupingSetData *gs = lfirst_node(GroupingSetData, lc2); - double numGroups = estimate_num_groups(root, - groupExprs, - path_rows, - &gset); - - gs->numGroups = numGroups; - rollup->numGroups += numGroups; - } - - dNumGroups += rollup->numGroups; - } - - if (gd->hash_sets_idx) - { - ListCell *lc; - - gd->dNumHashGroups = 0; - - groupExprs = get_sortgrouplist_exprs(parse->groupClause, - target_list); - - forboth(lc, gd->hash_sets_idx, lc2, gd->unsortable_sets) - { - List *gset = (List *) lfirst(lc); - GroupingSetData *gs = lfirst_node(GroupingSetData, lc2); - double numGroups = estimate_num_groups(root, - groupExprs, - path_rows, - &gset); - - gs->numGroups = numGroups; - gd->dNumHashGroups += numGroups; - } - - dNumGroups += gd->dNumHashGroups; - } - } - else - { - /* Plain GROUP BY */ - groupExprs = get_sortgrouplist_exprs(parse->groupClause, - target_list); - - dNumGroups = estimate_num_groups(root, groupExprs, path_rows, - NULL); - } - } - else if (parse->groupingSets) - { - /* Empty grouping sets ... one result row for each one */ - dNumGroups = list_length(parse->groupingSets); - } - else if (parse->hasAggs || root->hasHavingQual) - { - /* Plain aggregation, one result row */ - dNumGroups = 1; - } - else - { - /* Not grouping */ - dNumGroups = 1; - } - - return dNumGroups; -} - -/* - * estimate_hashagg_tablesize - * estimate the number of bytes that a hash aggregate hashtable will - * require based on the agg_costs, path width and dNumGroups. - * - * XXX this may be over-estimating the size now that hashagg knows to omit - * unneeded columns from the hashtable. Also for mixed-mode grouping sets, - * grouping columns not in the hashed set are counted here even though hashagg - * won't store them. Is this a problem? - */ -static Size -estimate_hashagg_tablesize(Path *path, const AggClauseCosts *agg_costs, - double dNumGroups) -{ - Size hashentrysize; - - /* Estimate per-hash-entry space at tuple width... */ - hashentrysize = MAXALIGN(path->pathtarget->width) + - MAXALIGN(SizeofMinimalTupleHeader); - - /* plus space for pass-by-ref transition values... */ - hashentrysize += agg_costs->transitionSpace; - /* plus the per-hash-entry overhead */ - hashentrysize += hash_agg_entry_size(agg_costs->numAggs); - - /* - * Note that this disregards the effect of fill-factor and growth policy - * of the hash-table. That's probably ok, given default the default - * fill-factor is relatively high. It'd be hard to meaningfully factor in - * "double-in-size" growth policies here. - */ - return hashentrysize * dNumGroups; -} - -/* - * create_grouping_paths - * - * Build a new upperrel containing Paths for grouping and/or aggregation. - * Along the way, we also build an upperrel for Paths which are partially - * grouped and/or aggregated. A partially grouped and/or aggregated path - * needs a FinalizeAggregate node to complete the aggregation. Currently, - * the only partially grouped paths we build are also partial paths; that - * is, they need a Gather and then a FinalizeAggregate. - * - * input_rel: contains the source-data Paths - * target: the pathtarget for the result Paths to compute - * agg_costs: cost info about all aggregates in query (in AGGSPLIT_SIMPLE mode) - * gd: grouping sets data including list of grouping sets and their clauses - * - * Note: all Paths in input_rel are expected to return the target computed - * by make_group_input_target. - */ -static RelOptInfo * -create_grouping_paths(PlannerInfo *root, - RelOptInfo *input_rel, - PathTarget *target, - bool target_parallel_safe, - const AggClauseCosts *agg_costs, - grouping_sets_data *gd) -{ - Query *parse = root->parse; - RelOptInfo *grouped_rel; - RelOptInfo *partially_grouped_rel; - - /* - * Create grouping relation to hold fully aggregated grouping and/or - * aggregation paths. - */ - grouped_rel = make_grouping_rel(root, input_rel, target, - target_parallel_safe, parse->havingQual); - - /* - * Create either paths for a degenerate grouping or paths for ordinary - * grouping, as appropriate. - */ - if (is_degenerate_grouping(root)) - create_degenerate_grouping_paths(root, input_rel, grouped_rel); - else - { - int flags = 0; - GroupPathExtraData extra; - - /* - * Determine whether it's possible to perform sort-based - * implementations of grouping. (Note that if groupClause is empty, - * grouping_is_sortable() is trivially true, and all the - * pathkeys_contained_in() tests will succeed too, so that we'll - * consider every surviving input path.) - * - * If we have grouping sets, we might be able to sort some but not all - * of them; in this case, we need can_sort to be true as long as we - * must consider any sorted-input plan. - */ - if ((gd && gd->rollups != NIL) - || grouping_is_sortable(parse->groupClause)) - flags |= GROUPING_CAN_USE_SORT; - - /* - * Determine whether we should consider hash-based implementations of - * grouping. - * - * Hashed aggregation only applies if we're grouping. If we have - * grouping sets, some groups might be hashable but others not; in - * this case we set can_hash true as long as there is nothing globally - * preventing us from hashing (and we should therefore consider plans - * with hashes). - * - * Executor doesn't support hashed aggregation with DISTINCT or ORDER - * BY aggregates. (Doing so would imply storing *all* the input - * values in the hash table, and/or running many sorts in parallel, - * either of which seems like a certain loser.) We similarly don't - * support ordered-set aggregates in hashed aggregation, but that case - * is also included in the numOrderedAggs count. - * - * Note: grouping_is_hashable() is much more expensive to check than - * the other gating conditions, so we want to do it last. - */ - if ((parse->groupClause != NIL && - agg_costs->numOrderedAggs == 0 && - (gd ? gd->any_hashable : grouping_is_hashable(parse->groupClause)))) - flags |= GROUPING_CAN_USE_HASH; - - /* - * Determine whether partial aggregation is possible. - */ - if (can_partial_agg(root, agg_costs)) - flags |= GROUPING_CAN_PARTIAL_AGG; - - extra.flags = flags; - extra.target_parallel_safe = target_parallel_safe; - extra.havingQual = parse->havingQual; - extra.targetList = parse->targetList; - extra.partial_costs_set = false; - - /* - * Determine whether partitionwise aggregation is in theory possible. - * It can be disabled by the user, and for now, we don't try to - * support grouping sets. create_ordinary_grouping_paths() will check - * additional conditions, such as whether input_rel is partitioned. - */ - if (enable_partitionwise_aggregate && !parse->groupingSets) - extra.patype = PARTITIONWISE_AGGREGATE_FULL; - else - extra.patype = PARTITIONWISE_AGGREGATE_NONE; - - create_ordinary_grouping_paths(root, input_rel, grouped_rel, - agg_costs, gd, &extra, - &partially_grouped_rel); - } - - set_cheapest(grouped_rel); - return grouped_rel; -} - -/* - * make_grouping_rel - * - * Create a new grouping rel and set basic properties. - * - * input_rel represents the underlying scan/join relation. - * target is the output expected from the grouping relation. - */ -static RelOptInfo * -make_grouping_rel(PlannerInfo *root, RelOptInfo *input_rel, - PathTarget *target, bool target_parallel_safe, - Node *havingQual) -{ - RelOptInfo *grouped_rel; - - if (IS_OTHER_REL(input_rel)) - { - grouped_rel = fetch_upper_rel(root, UPPERREL_GROUP_AGG, - input_rel->relids); - grouped_rel->reloptkind = RELOPT_OTHER_UPPER_REL; - } - else - { - /* - * By tradition, the relids set for the main grouping relation is - * NULL. (This could be changed, but might require adjustments - * elsewhere.) - */ - grouped_rel = fetch_upper_rel(root, UPPERREL_GROUP_AGG, NULL); - } - - /* Set target. */ - grouped_rel->reltarget = target; - - /* - * If the input relation is not parallel-safe, then the grouped relation - * can't be parallel-safe, either. Otherwise, it's parallel-safe if the - * target list and HAVING quals are parallel-safe. - */ - if (input_rel->consider_parallel && target_parallel_safe && - is_parallel_safe(root, (Node *) havingQual)) - grouped_rel->consider_parallel = true; - - /* - * If the input rel belongs to a single FDW, so does the grouped rel. - */ - grouped_rel->serverid = input_rel->serverid; - grouped_rel->userid = input_rel->userid; - grouped_rel->useridiscurrent = input_rel->useridiscurrent; - grouped_rel->fdwroutine = input_rel->fdwroutine; - - return grouped_rel; -} - -/* - * is_degenerate_grouping - * - * A degenerate grouping is one in which the query has a HAVING qual and/or - * grouping sets, but no aggregates and no GROUP BY (which implies that the - * grouping sets are all empty). - */ -static bool -is_degenerate_grouping(PlannerInfo *root) -{ - Query *parse = root->parse; - - return (root->hasHavingQual || parse->groupingSets) && - !parse->hasAggs && parse->groupClause == NIL; -} - -/* - * create_degenerate_grouping_paths - * - * When the grouping is degenerate (see is_degenerate_grouping), we are - * supposed to emit either zero or one row for each grouping set depending on - * whether HAVING succeeds. Furthermore, there cannot be any variables in - * either HAVING or the targetlist, so we actually do not need the FROM table - * at all! We can just throw away the plan-so-far and generate a Result node. - * This is a sufficiently unusual corner case that it's not worth contorting - * the structure of this module to avoid having to generate the earlier paths - * in the first place. - */ -static void -create_degenerate_grouping_paths(PlannerInfo *root, RelOptInfo *input_rel, - RelOptInfo *grouped_rel) -{ - Query *parse = root->parse; - int nrows; - Path *path; - - nrows = list_length(parse->groupingSets); - if (nrows > 1) - { - /* - * Doesn't seem worthwhile writing code to cons up a generate_series - * or a values scan to emit multiple rows. Instead just make N clones - * and append them. (With a volatile HAVING clause, this means you - * might get between 0 and N output rows. Offhand I think that's - * desired.) - */ - List *paths = NIL; - - while (--nrows >= 0) - { - path = (Path *) - create_result_path(root, grouped_rel, - grouped_rel->reltarget, - (List *) parse->havingQual); - paths = lappend(paths, path); - } - path = (Path *) - create_append_path(root, - grouped_rel, - paths, - NIL, - NULL, - 0, - false, - NIL, - -1); - } - else - { - /* No grouping sets, or just one, so one output row */ - path = (Path *) - create_result_path(root, grouped_rel, - grouped_rel->reltarget, - (List *) parse->havingQual); - } - - add_path(grouped_rel, path); -} - -/* - * create_ordinary_grouping_paths - * - * Create grouping paths for the ordinary (that is, non-degenerate) case. - * - * We need to consider sorted and hashed aggregation in the same function, - * because otherwise (1) it would be harder to throw an appropriate error - * message if neither way works, and (2) we should not allow hashtable size - * considerations to dissuade us from using hashing if sorting is not possible. - * - * *partially_grouped_rel_p will be set to the partially grouped rel which this - * function creates, or to NULL if it doesn't create one. - */ -static void -create_ordinary_grouping_paths(PlannerInfo *root, RelOptInfo *input_rel, - RelOptInfo *grouped_rel, - const AggClauseCosts *agg_costs, - grouping_sets_data *gd, - GroupPathExtraData *extra, - RelOptInfo **partially_grouped_rel_p) -{ - Path *cheapest_path = input_rel->cheapest_total_path; - RelOptInfo *partially_grouped_rel = NULL; - double dNumGroups; - PartitionwiseAggregateType patype = PARTITIONWISE_AGGREGATE_NONE; - - /* - * If this is the topmost grouping relation or if the parent relation is - * doing some form of partitionwise aggregation, then we may be able to do - * it at this level also. However, if the input relation is not - * partitioned, partitionwise aggregate is impossible, and if it is dummy, - * partitionwise aggregate is pointless. - */ - if (extra->patype != PARTITIONWISE_AGGREGATE_NONE && - input_rel->part_scheme && input_rel->part_rels && - !IS_DUMMY_REL(input_rel)) - { - /* - * If this is the topmost relation or if the parent relation is doing - * full partitionwise aggregation, then we can do full partitionwise - * aggregation provided that the GROUP BY clause contains all of the - * partitioning columns at this level. Otherwise, we can do at most - * partial partitionwise aggregation. But if partial aggregation is - * not supported in general then we can't use it for partitionwise - * aggregation either. - */ - if (extra->patype == PARTITIONWISE_AGGREGATE_FULL && - group_by_has_partkey(input_rel, extra->targetList, - root->parse->groupClause)) - patype = PARTITIONWISE_AGGREGATE_FULL; - else if ((extra->flags & GROUPING_CAN_PARTIAL_AGG) != 0) - patype = PARTITIONWISE_AGGREGATE_PARTIAL; - else - patype = PARTITIONWISE_AGGREGATE_NONE; - } - - /* - * Before generating paths for grouped_rel, we first generate any possible - * partially grouped paths; that way, later code can easily consider both - * parallel and non-parallel approaches to grouping. - */ - if ((extra->flags & GROUPING_CAN_PARTIAL_AGG) != 0) - { - bool force_rel_creation; - - /* - * If we're doing partitionwise aggregation at this level, force - * creation of a partially_grouped_rel so we can add partitionwise - * paths to it. - */ - force_rel_creation = (patype == PARTITIONWISE_AGGREGATE_PARTIAL); - - partially_grouped_rel = - create_partial_grouping_paths(root, - grouped_rel, - input_rel, - gd, - extra, - force_rel_creation); - } - - /* Set out parameter. */ - *partially_grouped_rel_p = partially_grouped_rel; - - /* Apply partitionwise aggregation technique, if possible. */ - if (patype != PARTITIONWISE_AGGREGATE_NONE) - create_partitionwise_grouping_paths(root, input_rel, grouped_rel, - partially_grouped_rel, agg_costs, - gd, patype, extra); - - /* If we are doing partial aggregation only, return. */ - if (extra->patype == PARTITIONWISE_AGGREGATE_PARTIAL) - { - Assert(partially_grouped_rel); - - if (partially_grouped_rel->pathlist) - set_cheapest(partially_grouped_rel); - - return; - } - - /* Gather any partially grouped partial paths. */ - if (partially_grouped_rel && partially_grouped_rel->partial_pathlist) - { - gather_grouping_paths(root, partially_grouped_rel); - set_cheapest(partially_grouped_rel); - } - - /* - * Estimate number of groups. - */ - dNumGroups = get_number_of_groups(root, - cheapest_path->rows, - gd, - extra->targetList); - - /* Build final grouping paths */ - add_paths_to_grouping_rel(root, input_rel, grouped_rel, - partially_grouped_rel, agg_costs, gd, - dNumGroups, extra); - - /* Give a helpful error if we failed to find any implementation */ - if (grouped_rel->pathlist == NIL) - ereport(ERROR, - (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), - errmsg("could not implement GROUP BY"), - errdetail("Some of the datatypes only support hashing, while others only support sorting."))); - - /* - * If there is an FDW that's responsible for all baserels of the query, - * let it consider adding ForeignPaths. - */ - if (grouped_rel->fdwroutine && - grouped_rel->fdwroutine->GetForeignUpperPaths) - grouped_rel->fdwroutine->GetForeignUpperPaths(root, UPPERREL_GROUP_AGG, - input_rel, grouped_rel, - extra); - - /* Let extensions possibly add some more paths */ - if (create_upper_paths_hook) - (*create_upper_paths_hook) (root, UPPERREL_GROUP_AGG, - input_rel, grouped_rel, - extra); -} - -/* - * For a given input path, consider the possible ways of doing grouping sets on - * it, by combinations of hashing and sorting. This can be called multiple - * times, so it's important that it not scribble on input. No result is - * returned, but any generated paths are added to grouped_rel. - */ -static void -consider_groupingsets_paths(PlannerInfo *root, - RelOptInfo *grouped_rel, - Path *path, - bool is_sorted, - bool can_hash, - grouping_sets_data *gd, - const AggClauseCosts *agg_costs, - double dNumGroups) -{ - Query *parse = root->parse; - - /* - * If we're not being offered sorted input, then only consider plans that - * can be done entirely by hashing. - * - * We can hash everything if it looks like it'll fit in work_mem. But if - * the input is actually sorted despite not being advertised as such, we - * prefer to make use of that in order to use less memory. - * - * If none of the grouping sets are sortable, then ignore the work_mem - * limit and generate a path anyway, since otherwise we'll just fail. - */ - if (!is_sorted) - { - List *new_rollups = NIL; - RollupData *unhashed_rollup = NULL; - List *sets_data; - List *empty_sets_data = NIL; - List *empty_sets = NIL; - ListCell *lc; - ListCell *l_start = list_head(gd->rollups); - AggStrategy strat = AGG_HASHED; - Size hashsize; - double exclude_groups = 0.0; - - Assert(can_hash); - - /* - * If the input is coincidentally sorted usefully (which can happen - * even if is_sorted is false, since that only means that our caller - * has set up the sorting for us), then save some hashtable space by - * making use of that. But we need to watch out for degenerate cases: - * - * 1) If there are any empty grouping sets, then group_pathkeys might - * be NIL if all non-empty grouping sets are unsortable. In this case, - * there will be a rollup containing only empty groups, and the - * pathkeys_contained_in test is vacuously true; this is ok. - * - * XXX: the above relies on the fact that group_pathkeys is generated - * from the first rollup. If we add the ability to consider multiple - * sort orders for grouping input, this assumption might fail. - * - * 2) If there are no empty sets and only unsortable sets, then the - * rollups list will be empty (and thus l_start == NULL), and - * group_pathkeys will be NIL; we must ensure that the vacuously-true - * pathkeys_contain_in test doesn't cause us to crash. - */ - if (l_start != NULL && - pathkeys_contained_in(root->group_pathkeys, path->pathkeys)) - { - unhashed_rollup = lfirst_node(RollupData, l_start); - exclude_groups = unhashed_rollup->numGroups; - l_start = lnext(l_start); - } - - hashsize = estimate_hashagg_tablesize(path, - agg_costs, - dNumGroups - exclude_groups); - - /* - * gd->rollups is empty if we have only unsortable columns to work - * with. Override work_mem in that case; otherwise, we'll rely on the - * sorted-input case to generate usable mixed paths. - */ - if (hashsize > work_mem * 1024L && gd->rollups) - return; /* nope, won't fit */ - - /* - * We need to burst the existing rollups list into individual grouping - * sets and recompute a groupClause for each set. - */ - sets_data = list_copy(gd->unsortable_sets); - - for_each_cell(lc, l_start) - { - RollupData *rollup = lfirst_node(RollupData, lc); - - /* - * If we find an unhashable rollup that's not been skipped by the - * "actually sorted" check above, we can't cope; we'd need sorted - * input (with a different sort order) but we can't get that here. - * So bail out; we'll get a valid path from the is_sorted case - * instead. - * - * The mere presence of empty grouping sets doesn't make a rollup - * unhashable (see preprocess_grouping_sets), we handle those - * specially below. - */ - if (!rollup->hashable) - return; - else - sets_data = list_concat(sets_data, list_copy(rollup->gsets_data)); - } - foreach(lc, sets_data) - { - GroupingSetData *gs = lfirst_node(GroupingSetData, lc); - List *gset = gs->set; - RollupData *rollup; - - if (gset == NIL) - { - /* Empty grouping sets can't be hashed. */ - empty_sets_data = lappend(empty_sets_data, gs); - empty_sets = lappend(empty_sets, NIL); - } - else - { - rollup = makeNode(RollupData); - - rollup->groupClause = preprocess_groupclause(root, gset); - rollup->gsets_data = list_make1(gs); - rollup->gsets = remap_to_groupclause_idx(rollup->groupClause, - rollup->gsets_data, - gd->tleref_to_colnum_map); - rollup->numGroups = gs->numGroups; - rollup->hashable = true; - rollup->is_hashed = true; - new_rollups = lappend(new_rollups, rollup); - } - } - - /* - * If we didn't find anything nonempty to hash, then bail. We'll - * generate a path from the is_sorted case. - */ - if (new_rollups == NIL) - return; - - /* - * If there were empty grouping sets they should have been in the - * first rollup. - */ - Assert(!unhashed_rollup || !empty_sets); - - if (unhashed_rollup) - { - new_rollups = lappend(new_rollups, unhashed_rollup); - strat = AGG_MIXED; - } - else if (empty_sets) - { - RollupData *rollup = makeNode(RollupData); - - rollup->groupClause = NIL; - rollup->gsets_data = empty_sets_data; - rollup->gsets = empty_sets; - rollup->numGroups = list_length(empty_sets); - rollup->hashable = false; - rollup->is_hashed = false; - new_rollups = lappend(new_rollups, rollup); - strat = AGG_MIXED; - } - - add_path(grouped_rel, (Path *) - create_groupingsets_path(root, - grouped_rel, - path, - (List *) parse->havingQual, - strat, - new_rollups, - agg_costs, - dNumGroups)); - return; - } - - /* - * If we have sorted input but nothing we can do with it, bail. - */ - if (list_length(gd->rollups) == 0) - return; - - /* - * Given sorted input, we try and make two paths: one sorted and one mixed - * sort/hash. (We need to try both because hashagg might be disabled, or - * some columns might not be sortable.) - * - * can_hash is passed in as false if some obstacle elsewhere (such as - * ordered aggs) means that we shouldn't consider hashing at all. - */ - if (can_hash && gd->any_hashable) - { - List *rollups = NIL; - List *hash_sets = list_copy(gd->unsortable_sets); - double availspace = (work_mem * 1024.0); - ListCell *lc; - - /* - * Account first for space needed for groups we can't sort at all. - */ - availspace -= (double) estimate_hashagg_tablesize(path, - agg_costs, - gd->dNumHashGroups); - - if (availspace > 0 && list_length(gd->rollups) > 1) - { - double scale; - int num_rollups = list_length(gd->rollups); - int k_capacity; - int *k_weights = palloc(num_rollups * sizeof(int)); - Bitmapset *hash_items = NULL; - int i; - - /* - * We treat this as a knapsack problem: the knapsack capacity - * represents work_mem, the item weights are the estimated memory - * usage of the hashtables needed to implement a single rollup, - * and we really ought to use the cost saving as the item value; - * however, currently the costs assigned to sort nodes don't - * reflect the comparison costs well, and so we treat all items as - * of equal value (each rollup we hash instead saves us one sort). - * - * To use the discrete knapsack, we need to scale the values to a - * reasonably small bounded range. We choose to allow a 5% error - * margin; we have no more than 4096 rollups in the worst possible - * case, which with a 5% error margin will require a bit over 42MB - * of workspace. (Anyone wanting to plan queries that complex had - * better have the memory for it. In more reasonable cases, with - * no more than a couple of dozen rollups, the memory usage will - * be negligible.) - * - * k_capacity is naturally bounded, but we clamp the values for - * scale and weight (below) to avoid overflows or underflows (or - * uselessly trying to use a scale factor less than 1 byte). - */ - scale = Max(availspace / (20.0 * num_rollups), 1.0); - k_capacity = (int) floor(availspace / scale); - - /* - * We leave the first rollup out of consideration since it's the - * one that matches the input sort order. We assign indexes "i" - * to only those entries considered for hashing; the second loop, - * below, must use the same condition. - */ - i = 0; - for_each_cell(lc, lnext(list_head(gd->rollups))) - { - RollupData *rollup = lfirst_node(RollupData, lc); - - if (rollup->hashable) - { - double sz = estimate_hashagg_tablesize(path, - agg_costs, - rollup->numGroups); - - /* - * If sz is enormous, but work_mem (and hence scale) is - * small, avoid integer overflow here. - */ - k_weights[i] = (int) Min(floor(sz / scale), - k_capacity + 1.0); - ++i; - } - } - - /* - * Apply knapsack algorithm; compute the set of items which - * maximizes the value stored (in this case the number of sorts - * saved) while keeping the total size (approximately) within - * capacity. - */ - if (i > 0) - hash_items = DiscreteKnapsack(k_capacity, i, k_weights, NULL); - - if (!bms_is_empty(hash_items)) - { - rollups = list_make1(linitial(gd->rollups)); - - i = 0; - for_each_cell(lc, lnext(list_head(gd->rollups))) - { - RollupData *rollup = lfirst_node(RollupData, lc); - - if (rollup->hashable) - { - if (bms_is_member(i, hash_items)) - hash_sets = list_concat(hash_sets, - list_copy(rollup->gsets_data)); - else - rollups = lappend(rollups, rollup); - ++i; - } - else - rollups = lappend(rollups, rollup); - } - } - } - - if (!rollups && hash_sets) - rollups = list_copy(gd->rollups); - - foreach(lc, hash_sets) - { - GroupingSetData *gs = lfirst_node(GroupingSetData, lc); - RollupData *rollup = makeNode(RollupData); - - Assert(gs->set != NIL); - - rollup->groupClause = preprocess_groupclause(root, gs->set); - rollup->gsets_data = list_make1(gs); - rollup->gsets = remap_to_groupclause_idx(rollup->groupClause, - rollup->gsets_data, - gd->tleref_to_colnum_map); - rollup->numGroups = gs->numGroups; - rollup->hashable = true; - rollup->is_hashed = true; - rollups = lcons(rollup, rollups); - } - - if (rollups) - { - add_path(grouped_rel, (Path *) - create_groupingsets_path(root, - grouped_rel, - path, - (List *) parse->havingQual, - AGG_MIXED, - rollups, - agg_costs, - dNumGroups)); - } - } - - /* - * Now try the simple sorted case. - */ - if (!gd->unsortable_sets) - add_path(grouped_rel, (Path *) - create_groupingsets_path(root, - grouped_rel, - path, - (List *) parse->havingQual, - AGG_SORTED, - gd->rollups, - agg_costs, - dNumGroups)); -} - -/* - * create_window_paths - * - * Build a new upperrel containing Paths for window-function evaluation. - * - * input_rel: contains the source-data Paths - * input_target: result of make_window_input_target - * output_target: what the topmost WindowAggPath should return - * tlist: query's target list (needed to look up pathkeys) - * wflists: result of find_window_functions - * activeWindows: result of select_active_windows - * - * Note: all Paths in input_rel are expected to return input_target. - */ -static RelOptInfo * -create_window_paths(PlannerInfo *root, - RelOptInfo *input_rel, - PathTarget *input_target, - PathTarget *output_target, - bool output_target_parallel_safe, - List *tlist, - WindowFuncLists *wflists, - List *activeWindows) -{ - RelOptInfo *window_rel; - ListCell *lc; - - /* For now, do all work in the (WINDOW, NULL) upperrel */ - window_rel = fetch_upper_rel(root, UPPERREL_WINDOW, NULL); - - /* - * If the input relation is not parallel-safe, then the window relation - * can't be parallel-safe, either. Otherwise, we need to examine the - * target list and active windows for non-parallel-safe constructs. - */ - if (input_rel->consider_parallel && output_target_parallel_safe && - is_parallel_safe(root, (Node *) activeWindows)) - window_rel->consider_parallel = true; - - /* - * If the input rel belongs to a single FDW, so does the window rel. - */ - window_rel->serverid = input_rel->serverid; - window_rel->userid = input_rel->userid; - window_rel->useridiscurrent = input_rel->useridiscurrent; - window_rel->fdwroutine = input_rel->fdwroutine; - - /* - * Consider computing window functions starting from the existing - * cheapest-total path (which will likely require a sort) as well as any - * existing paths that satisfy root->window_pathkeys (which won't). - */ - foreach(lc, input_rel->pathlist) - { - Path *path = (Path *) lfirst(lc); - - if (path == input_rel->cheapest_total_path || - pathkeys_contained_in(root->window_pathkeys, path->pathkeys)) - create_one_window_path(root, - window_rel, - path, - input_target, - output_target, - tlist, - wflists, - activeWindows); - } - - /* - * If there is an FDW that's responsible for all baserels of the query, - * let it consider adding ForeignPaths. - */ - if (window_rel->fdwroutine && - window_rel->fdwroutine->GetForeignUpperPaths) - window_rel->fdwroutine->GetForeignUpperPaths(root, UPPERREL_WINDOW, - input_rel, window_rel, - NULL); - - /* Let extensions possibly add some more paths */ - if (create_upper_paths_hook) - (*create_upper_paths_hook) (root, UPPERREL_WINDOW, - input_rel, window_rel, NULL); - - /* Now choose the best path(s) */ - set_cheapest(window_rel); - - return window_rel; -} - -/* - * Stack window-function implementation steps atop the given Path, and - * add the result to window_rel. - * - * window_rel: upperrel to contain result - * path: input Path to use (must return input_target) - * input_target: result of make_window_input_target - * output_target: what the topmost WindowAggPath should return - * tlist: query's target list (needed to look up pathkeys) - * wflists: result of find_window_functions - * activeWindows: result of select_active_windows - */ -static void -create_one_window_path(PlannerInfo *root, - RelOptInfo *window_rel, - Path *path, - PathTarget *input_target, - PathTarget *output_target, - List *tlist, - WindowFuncLists *wflists, - List *activeWindows) -{ - PathTarget *window_target; - ListCell *l; - - /* - * Since each window clause could require a different sort order, we stack - * up a WindowAgg node for each clause, with sort steps between them as - * needed. (We assume that select_active_windows chose a good order for - * executing the clauses in.) - * - * input_target should contain all Vars and Aggs needed for the result. - * (In some cases we wouldn't need to propagate all of these all the way - * to the top, since they might only be needed as inputs to WindowFuncs. - * It's probably not worth trying to optimize that though.) It must also - * contain all window partitioning and sorting expressions, to ensure - * they're computed only once at the bottom of the stack (that's critical - * for volatile functions). As we climb up the stack, we'll add outputs - * for the WindowFuncs computed at each level. - */ - window_target = input_target; - - foreach(l, activeWindows) - { - WindowClause *wc = lfirst_node(WindowClause, l); - List *window_pathkeys; - - window_pathkeys = make_pathkeys_for_window(root, - wc, - tlist); - - /* Sort if necessary */ - if (!pathkeys_contained_in(window_pathkeys, path->pathkeys)) - { - path = (Path *) create_sort_path(root, window_rel, - path, - window_pathkeys, - -1.0); - } - - if (lnext(l)) - { - /* - * Add the current WindowFuncs to the output target for this - * intermediate WindowAggPath. We must copy window_target to - * avoid changing the previous path's target. - * - * Note: a WindowFunc adds nothing to the target's eval costs; but - * we do need to account for the increase in tlist width. - */ - ListCell *lc2; - - window_target = copy_pathtarget(window_target); - foreach(lc2, wflists->windowFuncs[wc->winref]) - { - WindowFunc *wfunc = lfirst_node(WindowFunc, lc2); - - add_column_to_pathtarget(window_target, (Expr *) wfunc, 0); - window_target->width += get_typavgwidth(wfunc->wintype, -1); - } - } - else - { - /* Install the goal target in the topmost WindowAgg */ - window_target = output_target; - } - - path = (Path *) - create_windowagg_path(root, window_rel, path, window_target, - wflists->windowFuncs[wc->winref], - wc, - window_pathkeys); - } - - add_path(window_rel, path); -} - -/* - * create_distinct_paths - * - * Build a new upperrel containing Paths for SELECT DISTINCT evaluation. - * - * input_rel: contains the source-data Paths - * - * Note: input paths should already compute the desired pathtarget, since - * Sort/Unique won't project anything. - */ -static RelOptInfo * -create_distinct_paths(PlannerInfo *root, - RelOptInfo *input_rel) -{ - Query *parse = root->parse; - Path *cheapest_input_path = input_rel->cheapest_total_path; - RelOptInfo *distinct_rel; - double numDistinctRows; - bool allow_hash; - Path *path; - ListCell *lc; - - /* For now, do all work in the (DISTINCT, NULL) upperrel */ - distinct_rel = fetch_upper_rel(root, UPPERREL_DISTINCT, NULL); - - /* - * We don't compute anything at this level, so distinct_rel will be - * parallel-safe if the input rel is parallel-safe. In particular, if - * there is a DISTINCT ON (...) clause, any path for the input_rel will - * output those expressions, and will not be parallel-safe unless those - * expressions are parallel-safe. - */ - distinct_rel->consider_parallel = input_rel->consider_parallel; - - /* - * If the input rel belongs to a single FDW, so does the distinct_rel. - */ - distinct_rel->serverid = input_rel->serverid; - distinct_rel->userid = input_rel->userid; - distinct_rel->useridiscurrent = input_rel->useridiscurrent; - distinct_rel->fdwroutine = input_rel->fdwroutine; - - /* Estimate number of distinct rows there will be */ - if (parse->groupClause || parse->groupingSets || parse->hasAggs || - root->hasHavingQual) - { - /* - * If there was grouping or aggregation, use the number of input rows - * as the estimated number of DISTINCT rows (ie, assume the input is - * already mostly unique). - */ - numDistinctRows = cheapest_input_path->rows; - } - else - { - /* - * Otherwise, the UNIQUE filter has effects comparable to GROUP BY. - */ - List *distinctExprs; - - distinctExprs = get_sortgrouplist_exprs(parse->distinctClause, - parse->targetList); - numDistinctRows = estimate_num_groups(root, distinctExprs, - cheapest_input_path->rows, - NULL); - } - - /* - * Consider sort-based implementations of DISTINCT, if possible. - */ - if (grouping_is_sortable(parse->distinctClause)) - { - /* - * First, if we have any adequately-presorted paths, just stick a - * Unique node on those. Then consider doing an explicit sort of the - * cheapest input path and Unique'ing that. - * - * When we have DISTINCT ON, we must sort by the more rigorous of - * DISTINCT and ORDER BY, else it won't have the desired behavior. - * Also, if we do have to do an explicit sort, we might as well use - * the more rigorous ordering to avoid a second sort later. (Note - * that the parser will have ensured that one clause is a prefix of - * the other.) - */ - List *needed_pathkeys; - - if (parse->hasDistinctOn && - list_length(root->distinct_pathkeys) < - list_length(root->sort_pathkeys)) - needed_pathkeys = root->sort_pathkeys; - else - needed_pathkeys = root->distinct_pathkeys; - - foreach(lc, input_rel->pathlist) - { - Path *path = (Path *) lfirst(lc); - - if (pathkeys_contained_in(needed_pathkeys, path->pathkeys)) - { - add_path(distinct_rel, (Path *) - create_upper_unique_path(root, distinct_rel, - path, - list_length(root->distinct_pathkeys), - numDistinctRows)); - } - } - - /* For explicit-sort case, always use the more rigorous clause */ - if (list_length(root->distinct_pathkeys) < - list_length(root->sort_pathkeys)) - { - needed_pathkeys = root->sort_pathkeys; - /* Assert checks that parser didn't mess up... */ - Assert(pathkeys_contained_in(root->distinct_pathkeys, - needed_pathkeys)); - } - else - needed_pathkeys = root->distinct_pathkeys; - - path = cheapest_input_path; - if (!pathkeys_contained_in(needed_pathkeys, path->pathkeys)) - path = (Path *) create_sort_path(root, distinct_rel, - path, - needed_pathkeys, - -1.0); - - add_path(distinct_rel, (Path *) - create_upper_unique_path(root, distinct_rel, - path, - list_length(root->distinct_pathkeys), - numDistinctRows)); - } - - /* - * Consider hash-based implementations of DISTINCT, if possible. - * - * If we were not able to make any other types of path, we *must* hash or - * die trying. If we do have other choices, there are several things that - * should prevent selection of hashing: if the query uses DISTINCT ON - * (because it won't really have the expected behavior if we hash), or if - * enable_hashagg is off, or if it looks like the hashtable will exceed - * work_mem. - * - * Note: grouping_is_hashable() is much more expensive to check than the - * other gating conditions, so we want to do it last. - */ - if (distinct_rel->pathlist == NIL) - allow_hash = true; /* we have no alternatives */ - else if (parse->hasDistinctOn || !enable_hashagg) - allow_hash = false; /* policy-based decision not to hash */ - else - { - Size hashentrysize; - - /* Estimate per-hash-entry space at tuple width... */ - hashentrysize = MAXALIGN(cheapest_input_path->pathtarget->width) + - MAXALIGN(SizeofMinimalTupleHeader); - /* plus the per-hash-entry overhead */ - hashentrysize += hash_agg_entry_size(0); - - /* Allow hashing only if hashtable is predicted to fit in work_mem */ - allow_hash = (hashentrysize * numDistinctRows <= work_mem * 1024L); - } - - if (allow_hash && grouping_is_hashable(parse->distinctClause)) - { - /* Generate hashed aggregate path --- no sort needed */ - add_path(distinct_rel, (Path *) - create_agg_path(root, - distinct_rel, - cheapest_input_path, - cheapest_input_path->pathtarget, - AGG_HASHED, - AGGSPLIT_SIMPLE, - parse->distinctClause, - NIL, - NULL, - numDistinctRows)); - } - - /* Give a helpful error if we failed to find any implementation */ - if (distinct_rel->pathlist == NIL) - ereport(ERROR, - (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), - errmsg("could not implement DISTINCT"), - errdetail("Some of the datatypes only support hashing, while others only support sorting."))); - - /* - * If there is an FDW that's responsible for all baserels of the query, - * let it consider adding ForeignPaths. + * If we have a sortable GROUP BY clause, then we want a result sorted + * properly for grouping. Otherwise, if we have window functions to + * evaluate, we try to sort for the first window. Otherwise, if there's a + * sortable DISTINCT clause that's more rigorous than the ORDER BY clause, + * we try to produce output that's sufficiently well sorted for the + * DISTINCT. Otherwise, if there is an ORDER BY clause, we want to sort + * by the ORDER BY clause. + * + * Note: if we have both ORDER BY and GROUP BY, and ORDER BY is a superset + * of GROUP BY, it would be tempting to request sort by ORDER BY --- but + * that might just leave us failing to exploit an available sort order at + * all. Needs more thought. The choice for DISTINCT versus ORDER BY is + * much easier, since we know that the parser ensured that one is a + * superset of the other. */ - if (distinct_rel->fdwroutine && - distinct_rel->fdwroutine->GetForeignUpperPaths) - distinct_rel->fdwroutine->GetForeignUpperPaths(root, UPPERREL_DISTINCT, - input_rel, distinct_rel, - NULL); - - /* Let extensions possibly add some more paths */ - if (create_upper_paths_hook) - (*create_upper_paths_hook) (root, UPPERREL_DISTINCT, - input_rel, distinct_rel, NULL); - - /* Now choose the best path(s) */ - set_cheapest(distinct_rel); - - return distinct_rel; + if (root->group_pathkeys) + root->query_pathkeys = root->group_pathkeys; + else if (root->window_pathkeys) + root->query_pathkeys = root->window_pathkeys; + else if (list_length(root->distinct_pathkeys) > + list_length(root->sort_pathkeys)) + root->query_pathkeys = root->distinct_pathkeys; + else if (root->sort_pathkeys) + root->query_pathkeys = root->sort_pathkeys; + else + root->query_pathkeys = NIL; } /* - * create_ordered_paths - * - * Build a new upperrel containing Paths for ORDER BY evaluation. + * create_window_paths * - * All paths in the result must satisfy the ORDER BY ordering. - * The only new path we need consider is an explicit sort on the - * cheapest-total existing path. + * Build a new upperrel containing Paths for window-function evaluation. * * input_rel: contains the source-data Paths - * target: the output tlist the result Paths must emit - * limit_tuples: estimated bound on the number of output tuples, - * or -1 if no LIMIT or couldn't estimate + * input_target: result of make_window_input_target + * output_target: what the topmost WindowAggPath should return + * tlist: query's target list (needed to look up pathkeys) + * wflists: result of find_window_functions + * activeWindows: result of select_active_windows + * + * Note: all Paths in input_rel are expected to return input_target. */ static RelOptInfo * -create_ordered_paths(PlannerInfo *root, - RelOptInfo *input_rel, - PathTarget *target, - bool target_parallel_safe, - double limit_tuples) +create_window_paths(PlannerInfo *root, + RelOptInfo *input_rel, + PathTarget *input_target, + PathTarget *output_target, + bool output_target_parallel_safe, + List *tlist, + WindowFuncLists *wflists, + List *activeWindows) { - Path *cheapest_input_path = input_rel->cheapest_total_path; - RelOptInfo *ordered_rel; + RelOptInfo *window_rel; ListCell *lc; - /* For now, do all work in the (ORDERED, NULL) upperrel */ - ordered_rel = fetch_upper_rel(root, UPPERREL_ORDERED, NULL); + /* For now, do all work in the (WINDOW, NULL) upperrel */ + window_rel = fetch_upper_rel(root, UPPERREL_WINDOW, NULL); /* - * If the input relation is not parallel-safe, then the ordered relation - * can't be parallel-safe, either. Otherwise, it's parallel-safe if the - * target list is parallel-safe. + * If the input relation is not parallel-safe, then the window relation + * can't be parallel-safe, either. Otherwise, we need to examine the + * target list and active windows for non-parallel-safe constructs. */ - if (input_rel->consider_parallel && target_parallel_safe) - ordered_rel->consider_parallel = true; + if (input_rel->consider_parallel && output_target_parallel_safe && + is_parallel_safe(root, (Node *) activeWindows)) + window_rel->consider_parallel = true; /* - * If the input rel belongs to a single FDW, so does the ordered_rel. + * If the input rel belongs to a single FDW, so does the window rel. */ - ordered_rel->serverid = input_rel->serverid; - ordered_rel->userid = input_rel->userid; - ordered_rel->useridiscurrent = input_rel->useridiscurrent; - ordered_rel->fdwroutine = input_rel->fdwroutine; - - foreach(lc, input_rel->pathlist) - { - Path *path = (Path *) lfirst(lc); - bool is_sorted; - - is_sorted = pathkeys_contained_in(root->sort_pathkeys, - path->pathkeys); - if (path == cheapest_input_path || is_sorted) - { - if (!is_sorted) - { - /* An explicit sort here can take advantage of LIMIT */ - path = (Path *) create_sort_path(root, - ordered_rel, - path, - root->sort_pathkeys, - limit_tuples); - } - - /* Add projection step if needed */ - if (path->pathtarget != target) - path = apply_projection_to_path(root, ordered_rel, - path, target); - - add_path(ordered_rel, path); - } - } + window_rel->serverid = input_rel->serverid; + window_rel->userid = input_rel->userid; + window_rel->useridiscurrent = input_rel->useridiscurrent; + window_rel->fdwroutine = input_rel->fdwroutine; /* - * generate_gather_paths() will have already generated a simple Gather - * path for the best parallel path, if any, and the loop above will have - * considered sorting it. Similarly, generate_gather_paths() will also - * have generated order-preserving Gather Merge plans which can be used - * without sorting if they happen to match the sort_pathkeys, and the loop - * above will have handled those as well. However, there's one more - * possibility: it may make sense to sort the cheapest partial path - * according to the required output order and then use Gather Merge. + * Consider computing window functions starting from the existing + * cheapest-total path (which will likely require a sort) as well as any + * existing paths that satisfy root->window_pathkeys (which won't). */ - if (ordered_rel->consider_parallel && root->sort_pathkeys != NIL && - input_rel->partial_pathlist != NIL) + foreach(lc, input_rel->pathlist) { - Path *cheapest_partial_path; - - cheapest_partial_path = linitial(input_rel->partial_pathlist); - - /* - * If cheapest partial path doesn't need a sort, this is redundant - * with what's already been tried. - */ - if (!pathkeys_contained_in(root->sort_pathkeys, - cheapest_partial_path->pathkeys)) - { - Path *path; - double total_groups; - - path = (Path *) create_sort_path(root, - ordered_rel, - cheapest_partial_path, - root->sort_pathkeys, - limit_tuples); - - total_groups = cheapest_partial_path->rows * - cheapest_partial_path->parallel_workers; - path = (Path *) - create_gather_merge_path(root, ordered_rel, - path, - path->pathtarget, - root->sort_pathkeys, NULL, - &total_groups); - - /* Add projection step if needed */ - if (path->pathtarget != target) - path = apply_projection_to_path(root, ordered_rel, - path, target); + Path *path = (Path *) lfirst(lc); - add_path(ordered_rel, path); - } + if (path == input_rel->cheapest_total_path || + pathkeys_contained_in(root->window_pathkeys, path->pathkeys)) + create_one_window_path(root, + window_rel, + path, + input_target, + output_target, + tlist, + wflists, + activeWindows); } /* * If there is an FDW that's responsible for all baserels of the query, * let it consider adding ForeignPaths. */ - if (ordered_rel->fdwroutine && - ordered_rel->fdwroutine->GetForeignUpperPaths) - ordered_rel->fdwroutine->GetForeignUpperPaths(root, UPPERREL_ORDERED, - input_rel, ordered_rel, - NULL); + if (window_rel->fdwroutine && + window_rel->fdwroutine->GetForeignUpperPaths) + window_rel->fdwroutine->GetForeignUpperPaths(root, UPPERREL_WINDOW, + input_rel, window_rel, + NULL); /* Let extensions possibly add some more paths */ if (create_upper_paths_hook) - (*create_upper_paths_hook) (root, UPPERREL_ORDERED, - input_rel, ordered_rel, NULL); - - /* - * No need to bother with set_cheapest here; grouping_planner does not - * need us to do it. - */ - Assert(ordered_rel->pathlist != NIL); - - return ordered_rel; -} - - -/* - * make_group_input_target - * Generate appropriate PathTarget for initial input to grouping nodes. - * - * If there is grouping or aggregation, the scan/join subplan cannot emit - * the query's final targetlist; for example, it certainly can't emit any - * aggregate function calls. This routine generates the correct target - * for the scan/join subplan. - * - * The query target list passed from the parser already contains entries - * for all ORDER BY and GROUP BY expressions, but it will not have entries - * for variables used only in HAVING clauses; so we need to add those - * variables to the subplan target list. Also, we flatten all expressions - * except GROUP BY items into their component variables; other expressions - * will be computed by the upper plan nodes rather than by the subplan. - * For example, given a query like - * SELECT a+b,SUM(c+d) FROM table GROUP BY a+b; - * we want to pass this targetlist to the subplan: - * a+b,c,d - * where the a+b target will be used by the Sort/Group steps, and the - * other targets will be used for computing the final results. - * - * 'final_target' is the query's final target list (in PathTarget form) + (*create_upper_paths_hook) (root, UPPERREL_WINDOW, + input_rel, window_rel, NULL); + + /* Now choose the best path(s) */ + set_cheapest(window_rel); + + return window_rel; +} + +/* + * Stack window-function implementation steps atop the given Path, and + * add the result to window_rel. * - * The result is the PathTarget to be computed by the Paths returned from - * query_planner(). + * window_rel: upperrel to contain result + * path: input Path to use (must return input_target) + * input_target: result of make_window_input_target + * output_target: what the topmost WindowAggPath should return + * tlist: query's target list (needed to look up pathkeys) + * wflists: result of find_window_functions + * activeWindows: result of select_active_windows */ -static PathTarget * -make_group_input_target(PlannerInfo *root, PathTarget *final_target) +static void +create_one_window_path(PlannerInfo *root, + RelOptInfo *window_rel, + Path *path, + PathTarget *input_target, + PathTarget *output_target, + List *tlist, + WindowFuncLists *wflists, + List *activeWindows) { - Query *parse = root->parse; - PathTarget *input_target; - List *non_group_cols; - List *non_group_vars; - int i; - ListCell *lc; + PathTarget *window_target; + ListCell *l; /* - * We must build a target containing all grouping columns, plus any other - * Vars mentioned in the query's targetlist and HAVING qual. + * Since each window clause could require a different sort order, we stack + * up a WindowAgg node for each clause, with sort steps between them as + * needed. (We assume that select_active_windows chose a good order for + * executing the clauses in.) + * + * input_target should contain all Vars and Aggs needed for the result. + * (In some cases we wouldn't need to propagate all of these all the way + * to the top, since they might only be needed as inputs to WindowFuncs. + * It's probably not worth trying to optimize that though.) It must also + * contain all window partitioning and sorting expressions, to ensure + * they're computed only once at the bottom of the stack (that's critical + * for volatile functions). As we climb up the stack, we'll add outputs + * for the WindowFuncs computed at each level. */ - input_target = create_empty_pathtarget(); - non_group_cols = NIL; + window_target = input_target; - i = 0; - foreach(lc, final_target->exprs) + foreach(l, activeWindows) { - Expr *expr = (Expr *) lfirst(lc); - Index sgref = get_pathtarget_sortgroupref(final_target, i); + WindowClause *wc = lfirst_node(WindowClause, l); + List *window_pathkeys; - if (sgref && parse->groupClause && - get_sortgroupref_clause_noerr(sgref, parse->groupClause) != NULL) + window_pathkeys = make_pathkeys_for_window(root, + wc, + tlist); + + /* Sort if necessary */ + if (!pathkeys_contained_in(window_pathkeys, path->pathkeys)) + { + path = (Path *) create_sort_path(root, window_rel, + path, + window_pathkeys, + -1.0); + } + + if (lnext(l)) { /* - * It's a grouping column, so add it to the input target as-is. + * Add the current WindowFuncs to the output target for this + * intermediate WindowAggPath. We must copy window_target to + * avoid changing the previous path's target. + * + * Note: a WindowFunc adds nothing to the target's eval costs; but + * we do need to account for the increase in tlist width. */ - add_column_to_pathtarget(input_target, expr, sgref); + ListCell *lc2; + + window_target = copy_pathtarget(window_target); + foreach(lc2, wflists->windowFuncs[wc->winref]) + { + WindowFunc *wfunc = lfirst_node(WindowFunc, lc2); + + add_column_to_pathtarget(window_target, (Expr *) wfunc, 0); + window_target->width += get_typavgwidth(wfunc->wintype, -1); + } } else { - /* - * Non-grouping column, so just remember the expression for later - * call to pull_var_clause. - */ - non_group_cols = lappend(non_group_cols, expr); + /* Install the goal target in the topmost WindowAgg */ + window_target = output_target; } - i++; + path = (Path *) + create_windowagg_path(root, window_rel, path, window_target, + wflists->windowFuncs[wc->winref], + wc, + window_pathkeys); } - /* - * If there's a HAVING clause, we'll need the Vars it uses, too. - */ - if (parse->havingQual) - non_group_cols = lappend(non_group_cols, parse->havingQual); - - /* - * Pull out all the Vars mentioned in non-group cols (plus HAVING), and - * add them to the input target if not already present. (A Var used - * directly as a GROUP BY item will be present already.) Note this - * includes Vars used in resjunk items, so we are covering the needs of - * ORDER BY and window specifications. Vars used within Aggrefs and - * WindowFuncs will be pulled out here, too. - */ - non_group_vars = pull_var_clause((Node *) non_group_cols, - PVC_RECURSE_AGGREGATES | - PVC_RECURSE_WINDOWFUNCS | - PVC_INCLUDE_PLACEHOLDERS); - add_new_columns_to_pathtarget(input_target, non_group_vars); - - /* clean up cruft */ - list_free(non_group_vars); - list_free(non_group_cols); - - /* XXX this causes some redundant cost calculation ... */ - return set_pathtarget_cost_width(root, input_target); + add_path(window_rel, path); } /* - * make_partial_grouping_target - * Generate appropriate PathTarget for output of partial aggregate - * (or partial grouping, if there are no aggregates) nodes. + * create_distinct_paths * - * A partial aggregation node needs to emit all the same aggregates that - * a regular aggregation node would, plus any aggregates used in HAVING; - * except that the Aggref nodes should be marked as partial aggregates. + * Build a new upperrel containing Paths for SELECT DISTINCT evaluation. * - * In addition, we'd better emit any Vars and PlaceholderVars that are - * used outside of Aggrefs in the aggregation tlist and HAVING. (Presumably, - * these would be Vars that are grouped by or used in grouping expressions.) + * input_rel: contains the source-data Paths * - * grouping_target is the tlist to be emitted by the topmost aggregation step. - * havingQual represents the HAVING clause. + * Note: input paths should already compute the desired pathtarget, since + * Sort/Unique won't project anything. */ -static PathTarget * -make_partial_grouping_target(PlannerInfo *root, - PathTarget *grouping_target, - Node *havingQual) +static RelOptInfo * +create_distinct_paths(PlannerInfo *root, + RelOptInfo *input_rel) { Query *parse = root->parse; - PathTarget *partial_target; - List *non_group_cols; - List *non_group_exprs; - int i; + Path *cheapest_input_path = input_rel->cheapest_total_path; + RelOptInfo *distinct_rel; + double numDistinctRows; + bool allow_hash; + Path *path; ListCell *lc; - partial_target = create_empty_pathtarget(); - non_group_cols = NIL; - - i = 0; - foreach(lc, grouping_target->exprs) - { - Expr *expr = (Expr *) lfirst(lc); - Index sgref = get_pathtarget_sortgroupref(grouping_target, i); - - if (sgref && parse->groupClause && - get_sortgroupref_clause_noerr(sgref, parse->groupClause) != NULL) - { - /* - * It's a grouping column, so add it to the partial_target as-is. - * (This allows the upper agg step to repeat the grouping calcs.) - */ - add_column_to_pathtarget(partial_target, expr, sgref); - } - else - { - /* - * Non-grouping column, so just remember the expression for later - * call to pull_var_clause. - */ - non_group_cols = lappend(non_group_cols, expr); - } - - i++; - } + /* For now, do all work in the (DISTINCT, NULL) upperrel */ + distinct_rel = fetch_upper_rel(root, UPPERREL_DISTINCT, NULL); /* - * If there's a HAVING clause, we'll need the Vars/Aggrefs it uses, too. + * We don't compute anything at this level, so distinct_rel will be + * parallel-safe if the input rel is parallel-safe. In particular, if + * there is a DISTINCT ON (...) clause, any path for the input_rel will + * output those expressions, and will not be parallel-safe unless those + * expressions are parallel-safe. */ - if (havingQual) - non_group_cols = lappend(non_group_cols, havingQual); + distinct_rel->consider_parallel = input_rel->consider_parallel; /* - * Pull out all the Vars, PlaceHolderVars, and Aggrefs mentioned in - * non-group cols (plus HAVING), and add them to the partial_target if not - * already present. (An expression used directly as a GROUP BY item will - * be present already.) Note this includes Vars used in resjunk items, so - * we are covering the needs of ORDER BY and window specifications. + * If the input rel belongs to a single FDW, so does the distinct_rel. */ - non_group_exprs = pull_var_clause((Node *) non_group_cols, - PVC_INCLUDE_AGGREGATES | - PVC_RECURSE_WINDOWFUNCS | - PVC_INCLUDE_PLACEHOLDERS); + distinct_rel->serverid = input_rel->serverid; + distinct_rel->userid = input_rel->userid; + distinct_rel->useridiscurrent = input_rel->useridiscurrent; + distinct_rel->fdwroutine = input_rel->fdwroutine; + + /* Estimate number of distinct rows there will be */ + if (parse->groupClause || parse->groupingSets || parse->hasAggs || + root->hasHavingQual) + { + /* + * If there was grouping or aggregation, use the number of input rows + * as the estimated number of DISTINCT rows (ie, assume the input is + * already mostly unique). + */ + numDistinctRows = cheapest_input_path->rows; + } + else + { + /* + * Otherwise, the UNIQUE filter has effects comparable to GROUP BY. + */ + List *distinctExprs; - add_new_columns_to_pathtarget(partial_target, non_group_exprs); + distinctExprs = get_sortgrouplist_exprs(parse->distinctClause, + parse->targetList); + numDistinctRows = estimate_num_groups(root, distinctExprs, + cheapest_input_path->rows, + NULL); + } /* - * Adjust Aggrefs to put them in partial mode. At this point all Aggrefs - * are at the top level of the target list, so we can just scan the list - * rather than recursing through the expression trees. + * Consider sort-based implementations of DISTINCT, if possible. */ - foreach(lc, partial_target->exprs) + if (grouping_is_sortable(parse->distinctClause)) { - Aggref *aggref = (Aggref *) lfirst(lc); - - if (IsA(aggref, Aggref)) - { - Aggref *newaggref; - - /* - * We shouldn't need to copy the substructure of the Aggref node, - * but flat-copy the node itself to avoid damaging other trees. - */ - newaggref = makeNode(Aggref); - memcpy(newaggref, aggref, sizeof(Aggref)); + /* + * First, if we have any adequately-presorted paths, just stick a + * Unique node on those. Then consider doing an explicit sort of the + * cheapest input path and Unique'ing that. + * + * When we have DISTINCT ON, we must sort by the more rigorous of + * DISTINCT and ORDER BY, else it won't have the desired behavior. + * Also, if we do have to do an explicit sort, we might as well use + * the more rigorous ordering to avoid a second sort later. (Note + * that the parser will have ensured that one clause is a prefix of + * the other.) + */ + List *needed_pathkeys; - /* For now, assume serialization is required */ - mark_partial_aggref(newaggref, AGGSPLIT_INITIAL_SERIAL); + if (parse->hasDistinctOn && + list_length(root->distinct_pathkeys) < + list_length(root->sort_pathkeys)) + needed_pathkeys = root->sort_pathkeys; + else + needed_pathkeys = root->distinct_pathkeys; - lfirst(lc) = newaggref; - } - } + foreach(lc, input_rel->pathlist) + { + Path *path = (Path *) lfirst(lc); - /* clean up cruft */ - list_free(non_group_exprs); - list_free(non_group_cols); + if (pathkeys_contained_in(needed_pathkeys, path->pathkeys)) + { + add_path(distinct_rel, (Path *) + create_upper_unique_path(root, distinct_rel, + path, + list_length(root->distinct_pathkeys), + numDistinctRows)); + } + } - /* XXX this causes some redundant cost calculation ... */ - return set_pathtarget_cost_width(root, partial_target); -} + /* For explicit-sort case, always use the more rigorous clause */ + if (list_length(root->distinct_pathkeys) < + list_length(root->sort_pathkeys)) + { + needed_pathkeys = root->sort_pathkeys; + /* Assert checks that parser didn't mess up... */ + Assert(pathkeys_contained_in(root->distinct_pathkeys, + needed_pathkeys)); + } + else + needed_pathkeys = root->distinct_pathkeys; -/* - * mark_partial_aggref - * Adjust an Aggref to make it represent a partial-aggregation step. - * - * The Aggref node is modified in-place; caller must do any copying required. - */ -void -mark_partial_aggref(Aggref *agg, AggSplit aggsplit) -{ - /* aggtranstype should be computed by this point */ - Assert(OidIsValid(agg->aggtranstype)); - /* ... but aggsplit should still be as the parser left it */ - Assert(agg->aggsplit == AGGSPLIT_SIMPLE); + path = cheapest_input_path; + if (!pathkeys_contained_in(needed_pathkeys, path->pathkeys)) + path = (Path *) create_sort_path(root, distinct_rel, + path, + needed_pathkeys, + -1.0); - /* Mark the Aggref with the intended partial-aggregation mode */ - agg->aggsplit = aggsplit; + add_path(distinct_rel, (Path *) + create_upper_unique_path(root, distinct_rel, + path, + list_length(root->distinct_pathkeys), + numDistinctRows)); + } /* - * Adjust result type if needed. Normally, a partial aggregate returns - * the aggregate's transition type; but if that's INTERNAL and we're - * serializing, it returns BYTEA instead. + * Consider hash-based implementations of DISTINCT, if possible. + * + * If we were not able to make any other types of path, we *must* hash or + * die trying. If we do have other choices, there are several things that + * should prevent selection of hashing: if the query uses DISTINCT ON + * (because it won't really have the expected behavior if we hash), or if + * enable_hashagg is off, or if it looks like the hashtable will exceed + * work_mem. + * + * Note: grouping_is_hashable() is much more expensive to check than the + * other gating conditions, so we want to do it last. */ - if (DO_AGGSPLIT_SKIPFINAL(aggsplit)) - { - if (agg->aggtranstype == INTERNALOID && DO_AGGSPLIT_SERIALIZE(aggsplit)) - agg->aggtype = BYTEAOID; - else - agg->aggtype = agg->aggtranstype; - } -} - -/* - * postprocess_setop_tlist - * Fix up targetlist returned by plan_set_operations(). - * - * We need to transpose sort key info from the orig_tlist into new_tlist. - * NOTE: this would not be good enough if we supported resjunk sort keys - * for results of set operations --- then, we'd need to project a whole - * new tlist to evaluate the resjunk columns. For now, just ereport if we - * find any resjunk columns in orig_tlist. - */ -static List * -postprocess_setop_tlist(List *new_tlist, List *orig_tlist) -{ - ListCell *l; - ListCell *orig_tlist_item = list_head(orig_tlist); - - foreach(l, new_tlist) + if (distinct_rel->pathlist == NIL) + allow_hash = true; /* we have no alternatives */ + else if (parse->hasDistinctOn || !enable_hashagg) + allow_hash = false; /* policy-based decision not to hash */ + else { - TargetEntry *new_tle = lfirst_node(TargetEntry, l); - TargetEntry *orig_tle; + Size hashentrysize; - /* ignore resjunk columns in setop result */ - if (new_tle->resjunk) - continue; + /* Estimate per-hash-entry space at tuple width... */ + hashentrysize = MAXALIGN(cheapest_input_path->pathtarget->width) + + MAXALIGN(SizeofMinimalTupleHeader); + /* plus the per-hash-entry overhead */ + hashentrysize += hash_agg_entry_size(0); - Assert(orig_tlist_item != NULL); - orig_tle = lfirst_node(TargetEntry, orig_tlist_item); - orig_tlist_item = lnext(orig_tlist_item); - if (orig_tle->resjunk) /* should not happen */ - elog(ERROR, "resjunk output columns are not implemented"); - Assert(new_tle->resno == orig_tle->resno); - new_tle->ressortgroupref = orig_tle->ressortgroupref; + /* Allow hashing only if hashtable is predicted to fit in work_mem */ + allow_hash = (hashentrysize * numDistinctRows <= work_mem * 1024L); } - if (orig_tlist_item != NULL) - elog(ERROR, "resjunk output columns are not implemented"); - return new_tlist; -} - -/* - * select_active_windows - * Create a list of the "active" window clauses (ie, those referenced - * by non-deleted WindowFuncs) in the order they are to be executed. - */ -static List * -select_active_windows(PlannerInfo *root, WindowFuncLists *wflists) -{ - List *result; - List *actives; - ListCell *lc; - /* First, make a list of the active windows */ - actives = NIL; - foreach(lc, root->parse->windowClause) + if (allow_hash && grouping_is_hashable(parse->distinctClause)) { - WindowClause *wc = lfirst_node(WindowClause, lc); - - /* It's only active if wflists shows some related WindowFuncs */ - Assert(wc->winref <= wflists->maxWinRef); - if (wflists->windowFuncs[wc->winref] != NIL) - actives = lappend(actives, wc); + /* Generate hashed aggregate path --- no sort needed */ + add_path(distinct_rel, (Path *) + create_agg_path(root, + distinct_rel, + cheapest_input_path, + cheapest_input_path->pathtarget, + AGG_HASHED, + AGGSPLIT_SIMPLE, + parse->distinctClause, + NIL, + NULL, + numDistinctRows)); } + /* Give a helpful error if we failed to find any implementation */ + if (distinct_rel->pathlist == NIL) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("could not implement DISTINCT"), + errdetail("Some of the datatypes only support hashing, while others only support sorting."))); + /* - * Now, ensure that windows with identical partitioning/ordering clauses - * are adjacent in the list. This is required by the SQL standard, which - * says that only one sort is to be used for such windows, even if they - * are otherwise distinct (eg, different names or framing clauses). - * - * There is room to be much smarter here, for example detecting whether - * one window's sort keys are a prefix of another's (so that sorting for - * the latter would do for the former), or putting windows first that - * match a sort order available for the underlying query. For the moment - * we are content with meeting the spec. + * If there is an FDW that's responsible for all baserels of the query, + * let it consider adding ForeignPaths. */ - result = NIL; - while (actives != NIL) - { - WindowClause *wc = linitial_node(WindowClause, actives); - ListCell *prev; - ListCell *next; - - /* Move wc from actives to result */ - actives = list_delete_first(actives); - result = lappend(result, wc); + if (distinct_rel->fdwroutine && + distinct_rel->fdwroutine->GetForeignUpperPaths) + distinct_rel->fdwroutine->GetForeignUpperPaths(root, UPPERREL_DISTINCT, + input_rel, distinct_rel, + NULL); - /* Now move any matching windows from actives to result */ - prev = NULL; - for (lc = list_head(actives); lc; lc = next) - { - WindowClause *wc2 = lfirst_node(WindowClause, lc); + /* Let extensions possibly add some more paths */ + if (create_upper_paths_hook) + (*create_upper_paths_hook) (root, UPPERREL_DISTINCT, + input_rel, distinct_rel, NULL); - next = lnext(lc); - /* framing options are NOT to be compared here! */ - if (equal(wc->partitionClause, wc2->partitionClause) && - equal(wc->orderClause, wc2->orderClause)) - { - actives = list_delete_cell(actives, lc, prev); - result = lappend(result, wc2); - } - else - prev = lc; - } - } + /* Now choose the best path(s) */ + set_cheapest(distinct_rel); - return result; + return distinct_rel; } /* - * make_window_input_target - * Generate appropriate PathTarget for initial input to WindowAgg nodes. - * - * When the query has window functions, this function computes the desired - * target to be computed by the node just below the first WindowAgg. - * This tlist must contain all values needed to evaluate the window functions, - * compute the final target list, and perform any required final sort step. - * If multiple WindowAggs are needed, each intermediate one adds its window - * function results onto this base tlist; only the topmost WindowAgg computes - * the actual desired target list. - * - * This function is much like make_group_input_target, though not quite enough - * like it to share code. As in that function, we flatten most expressions - * into their component variables. But we do not want to flatten window - * PARTITION BY/ORDER BY clauses, since that might result in multiple - * evaluations of them, which would be bad (possibly even resulting in - * inconsistent answers, if they contain volatile functions). - * Also, we must not flatten GROUP BY clauses that were left unflattened by - * make_group_input_target, because we may no longer have access to the - * individual Vars in them. + * create_ordered_paths * - * Another key difference from make_group_input_target is that we don't - * flatten Aggref expressions, since those are to be computed below the - * window functions and just referenced like Vars above that. + * Build a new upperrel containing Paths for ORDER BY evaluation. * - * 'final_target' is the query's final target list (in PathTarget form) - * 'activeWindows' is the list of active windows previously identified by - * select_active_windows. + * All paths in the result must satisfy the ORDER BY ordering. + * The only new path we need consider is an explicit sort on the + * cheapest-total existing path. * - * The result is the PathTarget to be computed by the plan node immediately - * below the first WindowAgg node. + * input_rel: contains the source-data Paths + * target: the output tlist the result Paths must emit + * limit_tuples: estimated bound on the number of output tuples, + * or -1 if no LIMIT or couldn't estimate */ -static PathTarget * -make_window_input_target(PlannerInfo *root, - PathTarget *final_target, - List *activeWindows) +static RelOptInfo * +create_ordered_paths(PlannerInfo *root, + RelOptInfo *input_rel, + PathTarget *target, + bool target_parallel_safe, + double limit_tuples) { - Query *parse = root->parse; - PathTarget *input_target; - Bitmapset *sgrefs; - List *flattenable_cols; - List *flattenable_vars; - int i; + Path *cheapest_input_path = input_rel->cheapest_total_path; + RelOptInfo *ordered_rel; ListCell *lc; - Assert(parse->hasWindowFuncs); + /* For now, do all work in the (ORDERED, NULL) upperrel */ + ordered_rel = fetch_upper_rel(root, UPPERREL_ORDERED, NULL); /* - * Collect the sortgroupref numbers of window PARTITION/ORDER BY clauses - * into a bitmapset for convenient reference below. + * If the input relation is not parallel-safe, then the ordered relation + * can't be parallel-safe, either. Otherwise, it's parallel-safe if the + * target list is parallel-safe. */ - sgrefs = NULL; - foreach(lc, activeWindows) + if (input_rel->consider_parallel && target_parallel_safe) + ordered_rel->consider_parallel = true; + + /* + * If the input rel belongs to a single FDW, so does the ordered_rel. + */ + ordered_rel->serverid = input_rel->serverid; + ordered_rel->userid = input_rel->userid; + ordered_rel->useridiscurrent = input_rel->useridiscurrent; + ordered_rel->fdwroutine = input_rel->fdwroutine; + + foreach(lc, input_rel->pathlist) { - WindowClause *wc = lfirst_node(WindowClause, lc); - ListCell *lc2; + Path *path = (Path *) lfirst(lc); + bool is_sorted; - foreach(lc2, wc->partitionClause) + is_sorted = pathkeys_contained_in(root->sort_pathkeys, + path->pathkeys); + if (path == cheapest_input_path || is_sorted) { - SortGroupClause *sortcl = lfirst_node(SortGroupClause, lc2); + if (!is_sorted) + { + /* An explicit sort here can take advantage of LIMIT */ + path = (Path *) create_sort_path(root, + ordered_rel, + path, + root->sort_pathkeys, + limit_tuples); + } - sgrefs = bms_add_member(sgrefs, sortcl->tleSortGroupRef); - } - foreach(lc2, wc->orderClause) - { - SortGroupClause *sortcl = lfirst_node(SortGroupClause, lc2); + /* Add projection step if needed */ + if (path->pathtarget != target) + path = apply_projection_to_path(root, ordered_rel, + path, target); - sgrefs = bms_add_member(sgrefs, sortcl->tleSortGroupRef); + add_path(ordered_rel, path); } } - /* Add in sortgroupref numbers of GROUP BY clauses, too */ - foreach(lc, parse->groupClause) - { - SortGroupClause *grpcl = lfirst_node(SortGroupClause, lc); - - sgrefs = bms_add_member(sgrefs, grpcl->tleSortGroupRef); - } - /* - * Construct a target containing all the non-flattenable targetlist items, - * and save aside the others for a moment. + * generate_gather_paths() will have already generated a simple Gather + * path for the best parallel path, if any, and the loop above will have + * considered sorting it. Similarly, generate_gather_paths() will also + * have generated order-preserving Gather Merge plans which can be used + * without sorting if they happen to match the sort_pathkeys, and the loop + * above will have handled those as well. However, there's one more + * possibility: it may make sense to sort the cheapest partial path + * according to the required output order and then use Gather Merge. */ - input_target = create_empty_pathtarget(); - flattenable_cols = NIL; - - i = 0; - foreach(lc, final_target->exprs) + if (ordered_rel->consider_parallel && root->sort_pathkeys != NIL && + input_rel->partial_pathlist != NIL) { - Expr *expr = (Expr *) lfirst(lc); - Index sgref = get_pathtarget_sortgroupref(final_target, i); + Path *cheapest_partial_path; + + cheapest_partial_path = linitial(input_rel->partial_pathlist); /* - * Don't want to deconstruct window clauses or GROUP BY items. (Note - * that such items can't contain window functions, so it's okay to - * compute them below the WindowAgg nodes.) + * If cheapest partial path doesn't need a sort, this is redundant + * with what's already been tried. */ - if (sgref != 0 && bms_is_member(sgref, sgrefs)) - { - /* - * Don't want to deconstruct this value, so add it to the input - * target as-is. - */ - add_column_to_pathtarget(input_target, expr, sgref); - } - else + if (!pathkeys_contained_in(root->sort_pathkeys, + cheapest_partial_path->pathkeys)) { - /* - * Column is to be flattened, so just remember the expression for - * later call to pull_var_clause. - */ - flattenable_cols = lappend(flattenable_cols, expr); - } + Path *path; + double total_groups; - i++; + path = (Path *) create_sort_path(root, + ordered_rel, + cheapest_partial_path, + root->sort_pathkeys, + limit_tuples); + + total_groups = cheapest_partial_path->rows * + cheapest_partial_path->parallel_workers; + path = (Path *) + create_gather_merge_path(root, ordered_rel, + path, + path->pathtarget, + root->sort_pathkeys, NULL, + &total_groups); + + /* Add projection step if needed */ + if (path->pathtarget != target) + path = apply_projection_to_path(root, ordered_rel, + path, target); + + add_path(ordered_rel, path); + } } /* - * Pull out all the Vars and Aggrefs mentioned in flattenable columns, and - * add them to the input target if not already present. (Some might be - * there already because they're used directly as window/group clauses.) - * - * Note: it's essential to use PVC_INCLUDE_AGGREGATES here, so that any - * Aggrefs are placed in the Agg node's tlist and not left to be computed - * at higher levels. On the other hand, we should recurse into - * WindowFuncs to make sure their input expressions are available. + * If there is an FDW that's responsible for all baserels of the query, + * let it consider adding ForeignPaths. */ - flattenable_vars = pull_var_clause((Node *) flattenable_cols, - PVC_INCLUDE_AGGREGATES | - PVC_RECURSE_WINDOWFUNCS | - PVC_INCLUDE_PLACEHOLDERS); - add_new_columns_to_pathtarget(input_target, flattenable_vars); - - /* clean up cruft */ - list_free(flattenable_vars); - list_free(flattenable_cols); - - /* XXX this causes some redundant cost calculation ... */ - return set_pathtarget_cost_width(root, input_target); -} + if (ordered_rel->fdwroutine && + ordered_rel->fdwroutine->GetForeignUpperPaths) + ordered_rel->fdwroutine->GetForeignUpperPaths(root, UPPERREL_ORDERED, + input_rel, ordered_rel, + NULL); -/* - * make_pathkeys_for_window - * Create a pathkeys list describing the required input ordering - * for the given WindowClause. - * - * The required ordering is first the PARTITION keys, then the ORDER keys. - * In the future we might try to implement windowing using hashing, in which - * case the ordering could be relaxed, but for now we always sort. - * - * Caution: if you change this, see createplan.c's get_column_info_for_window! - */ -static List * -make_pathkeys_for_window(PlannerInfo *root, WindowClause *wc, - List *tlist) -{ - List *window_pathkeys; - List *window_sortclauses; + /* Let extensions possibly add some more paths */ + if (create_upper_paths_hook) + (*create_upper_paths_hook) (root, UPPERREL_ORDERED, + input_rel, ordered_rel, NULL); - /* Throw error if can't sort */ - if (!grouping_is_sortable(wc->partitionClause)) - ereport(ERROR, - (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), - errmsg("could not implement window PARTITION BY"), - errdetail("Window partitioning columns must be of sortable datatypes."))); - if (!grouping_is_sortable(wc->orderClause)) - ereport(ERROR, - (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), - errmsg("could not implement window ORDER BY"), - errdetail("Window ordering columns must be of sortable datatypes."))); + /* + * No need to bother with set_cheapest here; grouping_planner does not + * need us to do it. + */ + Assert(ordered_rel->pathlist != NIL); - /* Okay, make the combined pathkeys */ - window_sortclauses = list_concat(list_copy(wc->partitionClause), - list_copy(wc->orderClause)); - window_pathkeys = make_pathkeys_for_sortclauses(root, - window_sortclauses, - tlist); - list_free(window_sortclauses); - return window_pathkeys; + return ordered_rel; } + /* - * make_sort_input_target - * Generate appropriate PathTarget for initial input to Sort step. - * - * If the query has ORDER BY, this function chooses the target to be computed - * by the node just below the Sort (and DISTINCT, if any, since Unique can't - * project) steps. This might or might not be identical to the query's final - * output target. - * - * The main argument for keeping the sort-input tlist the same as the final - * is that we avoid a separate projection node (which will be needed if - * they're different, because Sort can't project). However, there are also - * advantages to postponing tlist evaluation till after the Sort: it ensures - * a consistent order of evaluation for any volatile functions in the tlist, - * and if there's also a LIMIT, we can stop the query without ever computing - * tlist functions for later rows, which is beneficial for both volatile and - * expensive functions. - * - * Our current policy is to postpone volatile expressions till after the sort - * unconditionally (assuming that that's possible, ie they are in plain tlist - * columns and not ORDER BY/GROUP BY/DISTINCT columns). We also prefer to - * postpone set-returning expressions, because running them beforehand would - * bloat the sort dataset, and because it might cause unexpected output order - * if the sort isn't stable. However there's a constraint on that: all SRFs - * in the tlist should be evaluated at the same plan step, so that they can - * run in sync in nodeProjectSet. So if any SRFs are in sort columns, we - * mustn't postpone any SRFs. (Note that in principle that policy should - * probably get applied to the group/window input targetlists too, but we - * have not done that historically.) Lastly, expensive expressions are - * postponed if there is a LIMIT, or if root->tuple_fraction shows that - * partial evaluation of the query is possible (if neither is true, we expect - * to have to evaluate the expressions for every row anyway), or if there are - * any volatile or set-returning expressions (since once we've put in a - * projection at all, it won't cost any more to postpone more stuff). - * - * Another issue that could potentially be considered here is that - * evaluating tlist expressions could result in data that's either wider - * or narrower than the input Vars, thus changing the volume of data that - * has to go through the Sort. However, we usually have only a very bad - * idea of the output width of any expression more complex than a Var, - * so for now it seems too risky to try to optimize on that basis. + * make_group_input_target + * Generate appropriate PathTarget for initial input to grouping nodes. * - * Note that if we do produce a modified sort-input target, and then the - * query ends up not using an explicit Sort, no particular harm is done: - * we'll initially use the modified target for the preceding path nodes, - * but then change them to the final target with apply_projection_to_path. - * Moreover, in such a case the guarantees about evaluation order of - * volatile functions still hold, since the rows are sorted already. + * If there is grouping or aggregation, the scan/join subplan cannot emit + * the query's final targetlist; for example, it certainly can't emit any + * aggregate function calls. This routine generates the correct target + * for the scan/join subplan. * - * This function has some things in common with make_group_input_target and - * make_window_input_target, though the detailed rules for what to do are - * different. We never flatten/postpone any grouping or ordering columns; - * those are needed before the sort. If we do flatten a particular - * expression, we leave Aggref and WindowFunc nodes alone, since those were - * computed earlier. + * The query target list passed from the parser already contains entries + * for all ORDER BY and GROUP BY expressions, but it will not have entries + * for variables used only in HAVING clauses; so we need to add those + * variables to the subplan target list. Also, we flatten all expressions + * except GROUP BY items into their component variables; other expressions + * will be computed by the upper plan nodes rather than by the subplan. + * For example, given a query like + * SELECT a+b,SUM(c+d) FROM table GROUP BY a+b; + * we want to pass this targetlist to the subplan: + * a+b,c,d + * where the a+b target will be used by the Sort/Group steps, and the + * other targets will be used for computing the final results. * * 'final_target' is the query's final target list (in PathTarget form) - * 'have_postponed_srfs' is an output argument, see below - * - * The result is the PathTarget to be computed by the plan node immediately - * below the Sort step (and the Distinct step, if any). This will be - * exactly final_target if we decide a projection step wouldn't be helpful. * - * In addition, *have_postponed_srfs is set to true if we choose to postpone - * any set-returning functions to after the Sort. + * The result is the PathTarget to be computed by the Paths returned from + * query_planner(). */ static PathTarget * -make_sort_input_target(PlannerInfo *root, - PathTarget *final_target, - bool *have_postponed_srfs) +make_group_input_target(PlannerInfo *root, PathTarget *final_target) { Query *parse = root->parse; PathTarget *input_target; - int ncols; - bool *col_is_srf; - bool *postpone_col; - bool have_srf; - bool have_volatile; - bool have_expensive; - bool have_srf_sortcols; - bool postpone_srfs; - List *postponable_cols; - List *postponable_vars; + List *non_group_cols; + List *non_group_vars; int i; ListCell *lc; - /* Shouldn't get here unless query has ORDER BY */ - Assert(parse->sortClause); - - *have_postponed_srfs = false; /* default result */ - - /* Inspect tlist and collect per-column information */ - ncols = list_length(final_target->exprs); - col_is_srf = (bool *) palloc0(ncols * sizeof(bool)); - postpone_col = (bool *) palloc0(ncols * sizeof(bool)); - have_srf = have_volatile = have_expensive = have_srf_sortcols = false; + /* + * We must build a target containing all grouping columns, plus any other + * Vars mentioned in the query's targetlist and HAVING qual. + */ + input_target = create_empty_pathtarget(); + non_group_cols = NIL; i = 0; foreach(lc, final_target->exprs) { Expr *expr = (Expr *) lfirst(lc); + Index sgref = get_pathtarget_sortgroupref(final_target, i); - /* - * If the column has a sortgroupref, assume it has to be evaluated - * before sorting. Generally such columns would be ORDER BY, GROUP - * BY, etc targets. One exception is columns that were removed from - * GROUP BY by remove_useless_groupby_columns() ... but those would - * only be Vars anyway. There don't seem to be any cases where it - * would be worth the trouble to double-check. - */ - if (get_pathtarget_sortgroupref(final_target, i) == 0) + if (sgref && parse->groupClause && + get_sortgroupref_clause_noerr(sgref, parse->groupClause) != NULL) { /* - * Check for SRF or volatile functions. Check the SRF case first - * because we must know whether we have any postponed SRFs. + * It's a grouping column, so add it to the input target as-is. */ - if (parse->hasTargetSRFs && - expression_returns_set((Node *) expr)) - { - /* We'll decide below whether these are postponable */ - col_is_srf[i] = true; - have_srf = true; - } - else if (contain_volatile_functions((Node *) expr)) - { - /* Unconditionally postpone */ - postpone_col[i] = true; - have_volatile = true; - } - else - { - /* - * Else check the cost. XXX it's annoying to have to do this - * when set_pathtarget_cost_width() just did it. Refactor to - * allow sharing the work? - */ - QualCost cost; - - cost_qual_eval_node(&cost, (Node *) expr, root); - - /* - * We arbitrarily define "expensive" as "more than 10X - * cpu_operator_cost". Note this will take in any PL function - * with default cost. - */ - if (cost.per_tuple > 10 * cpu_operator_cost) - { - postpone_col[i] = true; - have_expensive = true; - } - } + add_column_to_pathtarget(input_target, expr, sgref); } else { - /* For sortgroupref cols, just check if any contain SRFs */ - if (!have_srf_sortcols && - parse->hasTargetSRFs && - expression_returns_set((Node *) expr)) - have_srf_sortcols = true; + /* + * Non-grouping column, so just remember the expression for later + * call to pull_var_clause. + */ + non_group_cols = lappend(non_group_cols, expr); } i++; } /* - * We can postpone SRFs if we have some but none are in sortgroupref cols. - */ - postpone_srfs = (have_srf && !have_srf_sortcols); - - /* - * If we don't need a post-sort projection, just return final_target. + * If there's a HAVING clause, we'll need the Vars it uses, too. */ - if (!(postpone_srfs || have_volatile || - (have_expensive && - (parse->limitCount || root->tuple_fraction > 0)))) - return final_target; + if (parse->havingQual) + non_group_cols = lappend(non_group_cols, parse->havingQual); /* - * Report whether the post-sort projection will contain set-returning - * functions. This is important because it affects whether the Sort can - * rely on the query's LIMIT (if any) to bound the number of rows it needs - * to return. + * Pull out all the Vars mentioned in non-group cols (plus HAVING), and + * add them to the input target if not already present. (A Var used + * directly as a GROUP BY item will be present already.) Note this + * includes Vars used in resjunk items, so we are covering the needs of + * ORDER BY and window specifications. Vars used within Aggrefs and + * WindowFuncs will be pulled out here, too. */ - *have_postponed_srfs = postpone_srfs; + non_group_vars = pull_var_clause((Node *) non_group_cols, + PVC_RECURSE_AGGREGATES | + PVC_RECURSE_WINDOWFUNCS | + PVC_INCLUDE_PLACEHOLDERS); + add_new_columns_to_pathtarget(input_target, non_group_vars); - /* - * Construct the sort-input target, taking all non-postponable columns and - * then adding Vars, PlaceHolderVars, Aggrefs, and WindowFuncs found in - * the postponable ones. - */ - input_target = create_empty_pathtarget(); - postponable_cols = NIL; + /* clean up cruft */ + list_free(non_group_vars); + list_free(non_group_cols); - i = 0; - foreach(lc, final_target->exprs) - { - Expr *expr = (Expr *) lfirst(lc); + /* XXX this causes some redundant cost calculation ... */ + return set_pathtarget_cost_width(root, input_target); +} - if (postpone_col[i] || (postpone_srfs && col_is_srf[i])) - postponable_cols = lappend(postponable_cols, expr); - else - add_column_to_pathtarget(input_target, expr, - get_pathtarget_sortgroupref(final_target, i)); +/* + * mark_partial_aggref + * Adjust an Aggref to make it represent a partial-aggregation step. + * + * The Aggref node is modified in-place; caller must do any copying required. + */ +void +mark_partial_aggref(Aggref *agg, AggSplit aggsplit) +{ + /* aggtranstype should be computed by this point */ + Assert(OidIsValid(agg->aggtranstype)); + /* ... but aggsplit should still be as the parser left it */ + Assert(agg->aggsplit == AGGSPLIT_SIMPLE); - i++; - } + /* Mark the Aggref with the intended partial-aggregation mode */ + agg->aggsplit = aggsplit; /* - * Pull out all the Vars, Aggrefs, and WindowFuncs mentioned in - * postponable columns, and add them to the sort-input target if not - * already present. (Some might be there already.) We mustn't - * deconstruct Aggrefs or WindowFuncs here, since the projection node - * would be unable to recompute them. + * Adjust result type if needed. Normally, a partial aggregate returns + * the aggregate's transition type; but if that's INTERNAL and we're + * serializing, it returns BYTEA instead. */ - postponable_vars = pull_var_clause((Node *) postponable_cols, - PVC_INCLUDE_AGGREGATES | - PVC_INCLUDE_WINDOWFUNCS | - PVC_INCLUDE_PLACEHOLDERS); - add_new_columns_to_pathtarget(input_target, postponable_vars); - - /* clean up cruft */ - list_free(postponable_vars); - list_free(postponable_cols); - - /* XXX this represents even more redundant cost calculation ... */ - return set_pathtarget_cost_width(root, input_target); + if (DO_AGGSPLIT_SKIPFINAL(aggsplit)) + { + if (agg->aggtranstype == INTERNALOID && DO_AGGSPLIT_SERIALIZE(aggsplit)) + agg->aggtype = BYTEAOID; + else + agg->aggtype = agg->aggtranstype; + } } /* - * get_cheapest_fractional_path - * Find the cheapest path for retrieving a specified fraction of all - * the tuples expected to be returned by the given relation. - * - * We interpret tuple_fraction the same way as grouping_planner. + * postprocess_setop_tlist + * Fix up targetlist returned by plan_set_operations(). * - * We assume set_cheapest() has been run on the given rel. + * We need to transpose sort key info from the orig_tlist into new_tlist. + * NOTE: this would not be good enough if we supported resjunk sort keys + * for results of set operations --- then, we'd need to project a whole + * new tlist to evaluate the resjunk columns. For now, just ereport if we + * find any resjunk columns in orig_tlist. + */ +static List * +postprocess_setop_tlist(List *new_tlist, List *orig_tlist) +{ + ListCell *l; + ListCell *orig_tlist_item = list_head(orig_tlist); + + foreach(l, new_tlist) + { + TargetEntry *new_tle = lfirst_node(TargetEntry, l); + TargetEntry *orig_tle; + + /* ignore resjunk columns in setop result */ + if (new_tle->resjunk) + continue; + + Assert(orig_tlist_item != NULL); + orig_tle = lfirst_node(TargetEntry, orig_tlist_item); + orig_tlist_item = lnext(orig_tlist_item); + if (orig_tle->resjunk) /* should not happen */ + elog(ERROR, "resjunk output columns are not implemented"); + Assert(new_tle->resno == orig_tle->resno); + new_tle->ressortgroupref = orig_tle->ressortgroupref; + } + if (orig_tlist_item != NULL) + elog(ERROR, "resjunk output columns are not implemented"); + return new_tlist; +} + +/* + * select_active_windows + * Create a list of the "active" window clauses (ie, those referenced + * by non-deleted WindowFuncs) in the order they are to be executed. */ -Path * -get_cheapest_fractional_path(RelOptInfo *rel, double tuple_fraction) +static List * +select_active_windows(PlannerInfo *root, WindowFuncLists *wflists) { - Path *best_path = rel->cheapest_total_path; - ListCell *l; + List *result; + List *actives; + ListCell *lc; - /* If all tuples will be retrieved, just return the cheapest-total path */ - if (tuple_fraction <= 0.0) - return best_path; + /* First, make a list of the active windows */ + actives = NIL; + foreach(lc, root->parse->windowClause) + { + WindowClause *wc = lfirst_node(WindowClause, lc); - /* Convert absolute # of tuples to a fraction; no need to clamp to 0..1 */ - if (tuple_fraction >= 1.0 && best_path->rows > 0) - tuple_fraction /= best_path->rows; + /* It's only active if wflists shows some related WindowFuncs */ + Assert(wc->winref <= wflists->maxWinRef); + if (wflists->windowFuncs[wc->winref] != NIL) + actives = lappend(actives, wc); + } - foreach(l, rel->pathlist) + /* + * Now, ensure that windows with identical partitioning/ordering clauses + * are adjacent in the list. This is required by the SQL standard, which + * says that only one sort is to be used for such windows, even if they + * are otherwise distinct (eg, different names or framing clauses). + * + * There is room to be much smarter here, for example detecting whether + * one window's sort keys are a prefix of another's (so that sorting for + * the latter would do for the former), or putting windows first that + * match a sort order available for the underlying query. For the moment + * we are content with meeting the spec. + */ + result = NIL; + while (actives != NIL) { - Path *path = (Path *) lfirst(l); + WindowClause *wc = linitial_node(WindowClause, actives); + ListCell *prev; + ListCell *next; - if (path == rel->cheapest_total_path || - compare_fractional_path_costs(best_path, path, tuple_fraction) <= 0) - continue; + /* Move wc from actives to result */ + actives = list_delete_first(actives); + result = lappend(result, wc); - best_path = path; + /* Now move any matching windows from actives to result */ + prev = NULL; + for (lc = list_head(actives); lc; lc = next) + { + WindowClause *wc2 = lfirst_node(WindowClause, lc); + + next = lnext(lc); + /* framing options are NOT to be compared here! */ + if (equal(wc->partitionClause, wc2->partitionClause) && + equal(wc->orderClause, wc2->orderClause)) + { + actives = list_delete_cell(actives, lc, prev); + result = lappend(result, wc2); + } + else + prev = lc; + } } - return best_path; + return result; } /* - * adjust_paths_for_srfs - * Fix up the Paths of the given upperrel to handle tSRFs properly. + * make_window_input_target + * Generate appropriate PathTarget for initial input to WindowAgg nodes. * - * The executor can only handle set-returning functions that appear at the - * top level of the targetlist of a ProjectSet plan node. If we have any SRFs - * that are not at top level, we need to split up the evaluation into multiple - * plan levels in which each level satisfies this constraint. This function - * modifies each Path of an upperrel that (might) compute any SRFs in its - * output tlist to insert appropriate projection steps. + * When the query has window functions, this function computes the desired + * target to be computed by the node just below the first WindowAgg. + * This tlist must contain all values needed to evaluate the window functions, + * compute the final target list, and perform any required final sort step. + * If multiple WindowAggs are needed, each intermediate one adds its window + * function results onto this base tlist; only the topmost WindowAgg computes + * the actual desired target list. * - * The given targets and targets_contain_srfs lists are from - * split_pathtarget_at_srfs(). We assume the existing Paths emit the first - * target in targets. + * This function is much like make_group_input_target, though not quite enough + * like it to share code. As in that function, we flatten most expressions + * into their component variables. But we do not want to flatten window + * PARTITION BY/ORDER BY clauses, since that might result in multiple + * evaluations of them, which would be bad (possibly even resulting in + * inconsistent answers, if they contain volatile functions). + * Also, we must not flatten GROUP BY clauses that were left unflattened by + * make_group_input_target, because we may no longer have access to the + * individual Vars in them. + * + * Another key difference from make_group_input_target is that we don't + * flatten Aggref expressions, since those are to be computed below the + * window functions and just referenced like Vars above that. + * + * 'final_target' is the query's final target list (in PathTarget form) + * 'activeWindows' is the list of active windows previously identified by + * select_active_windows. + * + * The result is the PathTarget to be computed by the plan node immediately + * below the first WindowAgg node. */ -static void -adjust_paths_for_srfs(PlannerInfo *root, RelOptInfo *rel, - List *targets, List *targets_contain_srfs) +static PathTarget * +make_window_input_target(PlannerInfo *root, + PathTarget *final_target, + List *activeWindows) { + Query *parse = root->parse; + PathTarget *input_target; + Bitmapset *sgrefs; + List *flattenable_cols; + List *flattenable_vars; + int i; ListCell *lc; - Assert(list_length(targets) == list_length(targets_contain_srfs)); - Assert(!linitial_int(targets_contain_srfs)); - - /* If no SRFs appear at this plan level, nothing to do */ - if (list_length(targets) == 1) - return; + Assert(parse->hasWindowFuncs); /* - * Stack SRF-evaluation nodes atop each path for the rel. - * - * In principle we should re-run set_cheapest() here to identify the - * cheapest path, but it seems unlikely that adding the same tlist eval - * costs to all the paths would change that, so we don't bother. Instead, - * just assume that the cheapest-startup and cheapest-total paths remain - * so. (There should be no parameterized paths anymore, so we needn't - * worry about updating cheapest_parameterized_paths.) + * Collect the sortgroupref numbers of window PARTITION/ORDER BY clauses + * into a bitmapset for convenient reference below. */ - foreach(lc, rel->pathlist) + sgrefs = NULL; + foreach(lc, activeWindows) { - Path *subpath = (Path *) lfirst(lc); - Path *newpath = subpath; - ListCell *lc1, - *lc2; + WindowClause *wc = lfirst_node(WindowClause, lc); + ListCell *lc2; - Assert(subpath->param_info == NULL); - forboth(lc1, targets, lc2, targets_contain_srfs) + foreach(lc2, wc->partitionClause) { - PathTarget *thistarget = lfirst_node(PathTarget, lc1); - bool contains_srfs = (bool) lfirst_int(lc2); + SortGroupClause *sortcl = lfirst_node(SortGroupClause, lc2); - /* If this level doesn't contain SRFs, do regular projection */ - if (contains_srfs) - newpath = (Path *) create_set_projection_path(root, - rel, - newpath, - thistarget); - else - newpath = (Path *) apply_projection_to_path(root, - rel, - newpath, - thistarget); + sgrefs = bms_add_member(sgrefs, sortcl->tleSortGroupRef); + } + foreach(lc2, wc->orderClause) + { + SortGroupClause *sortcl = lfirst_node(SortGroupClause, lc2); + + sgrefs = bms_add_member(sgrefs, sortcl->tleSortGroupRef); } - lfirst(lc) = newpath; - if (subpath == rel->cheapest_startup_path) - rel->cheapest_startup_path = newpath; - if (subpath == rel->cheapest_total_path) - rel->cheapest_total_path = newpath; } - /* Likewise for partial paths, if any */ - foreach(lc, rel->partial_pathlist) + /* Add in sortgroupref numbers of GROUP BY clauses, too */ + foreach(lc, parse->groupClause) { - Path *subpath = (Path *) lfirst(lc); - Path *newpath = subpath; - ListCell *lc1, - *lc2; + SortGroupClause *grpcl = lfirst_node(SortGroupClause, lc); - Assert(subpath->param_info == NULL); - forboth(lc1, targets, lc2, targets_contain_srfs) - { - PathTarget *thistarget = lfirst_node(PathTarget, lc1); - bool contains_srfs = (bool) lfirst_int(lc2); + sgrefs = bms_add_member(sgrefs, grpcl->tleSortGroupRef); + } - /* If this level doesn't contain SRFs, do regular projection */ - if (contains_srfs) - newpath = (Path *) create_set_projection_path(root, - rel, - newpath, - thistarget); - else - { - /* avoid apply_projection_to_path, in case of multiple refs */ - newpath = (Path *) create_projection_path(root, - rel, - newpath, - thistarget); - } + /* + * Construct a target containing all the non-flattenable targetlist items, + * and save aside the others for a moment. + */ + input_target = create_empty_pathtarget(); + flattenable_cols = NIL; + + i = 0; + foreach(lc, final_target->exprs) + { + Expr *expr = (Expr *) lfirst(lc); + Index sgref = get_pathtarget_sortgroupref(final_target, i); + + /* + * Don't want to deconstruct window clauses or GROUP BY items. (Note + * that such items can't contain window functions, so it's okay to + * compute them below the WindowAgg nodes.) + */ + if (sgref != 0 && bms_is_member(sgref, sgrefs)) + { + /* + * Don't want to deconstruct this value, so add it to the input + * target as-is. + */ + add_column_to_pathtarget(input_target, expr, sgref); } - lfirst(lc) = newpath; + else + { + /* + * Column is to be flattened, so just remember the expression for + * later call to pull_var_clause. + */ + flattenable_cols = lappend(flattenable_cols, expr); + } + + i++; } + + /* + * Pull out all the Vars and Aggrefs mentioned in flattenable columns, and + * add them to the input target if not already present. (Some might be + * there already because they're used directly as window/group clauses.) + * + * Note: it's essential to use PVC_INCLUDE_AGGREGATES here, so that any + * Aggrefs are placed in the Agg node's tlist and not left to be computed + * at higher levels. On the other hand, we should recurse into + * WindowFuncs to make sure their input expressions are available. + */ + flattenable_vars = pull_var_clause((Node *) flattenable_cols, + PVC_INCLUDE_AGGREGATES | + PVC_RECURSE_WINDOWFUNCS | + PVC_INCLUDE_PLACEHOLDERS); + add_new_columns_to_pathtarget(input_target, flattenable_vars); + + /* clean up cruft */ + list_free(flattenable_vars); + list_free(flattenable_cols); + + /* XXX this causes some redundant cost calculation ... */ + return set_pathtarget_cost_width(root, input_target); } /* - * expression_planner - * Perform planner's transformations on a standalone expression. - * - * Various utility commands need to evaluate expressions that are not part - * of a plannable query. They can do so using the executor's regular - * expression-execution machinery, but first the expression has to be fed - * through here to transform it from parser output to something executable. + * make_pathkeys_for_window + * Create a pathkeys list describing the required input ordering + * for the given WindowClause. * - * Currently, we disallow sublinks in standalone expressions, so there's no - * real "planning" involved here. (That might not always be true though.) - * What we must do is run eval_const_expressions to ensure that any function - * calls are converted to positional notation and function default arguments - * get inserted. The fact that constant subexpressions get simplified is a - * side-effect that is useful when the expression will get evaluated more than - * once. Also, we must fix operator function IDs. + * The required ordering is first the PARTITION keys, then the ORDER keys. + * In the future we might try to implement windowing using hashing, in which + * case the ordering could be relaxed, but for now we always sort. * - * Note: this must not make any damaging changes to the passed-in expression - * tree. (It would actually be okay to apply fix_opfuncids to it, but since - * we first do an expression_tree_mutator-based walk, what is returned will - * be a new node tree.) + * Caution: if you change this, see createplan.c's get_column_info_for_window! */ -Expr * -expression_planner(Expr *expr) +static List * +make_pathkeys_for_window(PlannerInfo *root, WindowClause *wc, + List *tlist) { - Node *result; - - /* - * Convert named-argument function calls, insert default arguments and - * simplify constant subexprs - */ - result = eval_const_expressions(NULL, (Node *) expr); + List *window_pathkeys; + List *window_sortclauses; - /* Fill in opfuncid values if missing */ - fix_opfuncids(result); + /* Throw error if can't sort */ + if (!grouping_is_sortable(wc->partitionClause)) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("could not implement window PARTITION BY"), + errdetail("Window partitioning columns must be of sortable datatypes."))); + if (!grouping_is_sortable(wc->orderClause)) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("could not implement window ORDER BY"), + errdetail("Window ordering columns must be of sortable datatypes."))); - return (Expr *) result; + /* Okay, make the combined pathkeys */ + window_sortclauses = list_concat(list_copy(wc->partitionClause), + list_copy(wc->orderClause)); + window_pathkeys = make_pathkeys_for_sortclauses(root, + window_sortclauses, + tlist); + list_free(window_sortclauses); + return window_pathkeys; } - /* - * plan_cluster_use_sort - * Use the planner to decide how CLUSTER should implement sorting + * make_sort_input_target + * Generate appropriate PathTarget for initial input to Sort step. * - * tableOid is the OID of a table to be clustered on its index indexOid - * (which is already known to be a btree index). Decide whether it's - * cheaper to do an indexscan or a seqscan-plus-sort to execute the CLUSTER. - * Return true to use sorting, false to use an indexscan. + * If the query has ORDER BY, this function chooses the target to be computed + * by the node just below the Sort (and DISTINCT, if any, since Unique can't + * project) steps. This might or might not be identical to the query's final + * output target. * - * Note: caller had better already hold some type of lock on the table. + * The main argument for keeping the sort-input tlist the same as the final + * is that we avoid a separate projection node (which will be needed if + * they're different, because Sort can't project). However, there are also + * advantages to postponing tlist evaluation till after the Sort: it ensures + * a consistent order of evaluation for any volatile functions in the tlist, + * and if there's also a LIMIT, we can stop the query without ever computing + * tlist functions for later rows, which is beneficial for both volatile and + * expensive functions. + * + * Our current policy is to postpone volatile expressions till after the sort + * unconditionally (assuming that that's possible, ie they are in plain tlist + * columns and not ORDER BY/GROUP BY/DISTINCT columns). We also prefer to + * postpone set-returning expressions, because running them beforehand would + * bloat the sort dataset, and because it might cause unexpected output order + * if the sort isn't stable. However there's a constraint on that: all SRFs + * in the tlist should be evaluated at the same plan step, so that they can + * run in sync in nodeProjectSet. So if any SRFs are in sort columns, we + * mustn't postpone any SRFs. (Note that in principle that policy should + * probably get applied to the group/window input targetlists too, but we + * have not done that historically.) Lastly, expensive expressions are + * postponed if there is a LIMIT, or if root->tuple_fraction shows that + * partial evaluation of the query is possible (if neither is true, we expect + * to have to evaluate the expressions for every row anyway), or if there are + * any volatile or set-returning expressions (since once we've put in a + * projection at all, it won't cost any more to postpone more stuff). + * + * Another issue that could potentially be considered here is that + * evaluating tlist expressions could result in data that's either wider + * or narrower than the input Vars, thus changing the volume of data that + * has to go through the Sort. However, we usually have only a very bad + * idea of the output width of any expression more complex than a Var, + * so for now it seems too risky to try to optimize on that basis. + * + * Note that if we do produce a modified sort-input target, and then the + * query ends up not using an explicit Sort, no particular harm is done: + * we'll initially use the modified target for the preceding path nodes, + * but then change them to the final target with apply_projection_to_path. + * Moreover, in such a case the guarantees about evaluation order of + * volatile functions still hold, since the rows are sorted already. + * + * This function has some things in common with make_group_input_target and + * make_window_input_target, though the detailed rules for what to do are + * different. We never flatten/postpone any grouping or ordering columns; + * those are needed before the sort. If we do flatten a particular + * expression, we leave Aggref and WindowFunc nodes alone, since those were + * computed earlier. + * + * 'final_target' is the query's final target list (in PathTarget form) + * 'have_postponed_srfs' is an output argument, see below + * + * The result is the PathTarget to be computed by the plan node immediately + * below the Sort step (and the Distinct step, if any). This will be + * exactly final_target if we decide a projection step wouldn't be helpful. + * + * In addition, *have_postponed_srfs is set to true if we choose to postpone + * any set-returning functions to after the Sort. */ -bool -plan_cluster_use_sort(Oid tableOid, Oid indexOid) +static PathTarget * +make_sort_input_target(PlannerInfo *root, + PathTarget *final_target, + bool *have_postponed_srfs) { - PlannerInfo *root; - Query *query; - PlannerGlobal *glob; - RangeTblEntry *rte; - RelOptInfo *rel; - IndexOptInfo *indexInfo; - QualCost indexExprCost; - Cost comparisonCost; - Path *seqScanPath; - Path seqScanAndSortPath; - IndexPath *indexScanPath; + Query *parse = root->parse; + PathTarget *input_target; + int ncols; + bool *col_is_srf; + bool *postpone_col; + bool have_srf; + bool have_volatile; + bool have_expensive; + bool have_srf_sortcols; + bool postpone_srfs; + List *postponable_cols; + List *postponable_vars; + int i; ListCell *lc; - /* We can short-circuit the cost comparison if indexscans are disabled */ - if (!enable_indexscan) - return true; /* use sort */ + /* Shouldn't get here unless query has ORDER BY */ + Assert(parse->sortClause); - /* Set up mostly-dummy planner state */ - query = makeNode(Query); - query->commandType = CMD_SELECT; + *have_postponed_srfs = false; /* default result */ - glob = makeNode(PlannerGlobal); + /* Inspect tlist and collect per-column information */ + ncols = list_length(final_target->exprs); + col_is_srf = (bool *) palloc0(ncols * sizeof(bool)); + postpone_col = (bool *) palloc0(ncols * sizeof(bool)); + have_srf = have_volatile = have_expensive = have_srf_sortcols = false; - root = makeNode(PlannerInfo); - root->parse = query; - root->glob = glob; - root->query_level = 1; - root->planner_cxt = CurrentMemoryContext; - root->wt_param_id = -1; + i = 0; + foreach(lc, final_target->exprs) + { + Expr *expr = (Expr *) lfirst(lc); - /* Build a minimal RTE for the rel */ - rte = makeNode(RangeTblEntry); - rte->rtekind = RTE_RELATION; - rte->relid = tableOid; - rte->relkind = RELKIND_RELATION; /* Don't be too picky. */ - rte->lateral = false; - rte->inh = false; - rte->inFromCl = true; - query->rtable = list_make1(rte); + /* + * If the column has a sortgroupref, assume it has to be evaluated + * before sorting. Generally such columns would be ORDER BY, GROUP + * BY, etc targets. One exception is columns that were removed from + * GROUP BY by remove_useless_groupby_columns() ... but those would + * only be Vars anyway. There don't seem to be any cases where it + * would be worth the trouble to double-check. + */ + if (get_pathtarget_sortgroupref(final_target, i) == 0) + { + /* + * Check for SRF or volatile functions. Check the SRF case first + * because we must know whether we have any postponed SRFs. + */ + if (parse->hasTargetSRFs && + expression_returns_set((Node *) expr)) + { + /* We'll decide below whether these are postponable */ + col_is_srf[i] = true; + have_srf = true; + } + else if (contain_volatile_functions((Node *) expr)) + { + /* Unconditionally postpone */ + postpone_col[i] = true; + have_volatile = true; + } + else + { + /* + * Else check the cost. XXX it's annoying to have to do this + * when set_pathtarget_cost_width() just did it. Refactor to + * allow sharing the work? + */ + QualCost cost; - /* Set up RTE/RelOptInfo arrays */ - setup_simple_rel_arrays(root); + cost_qual_eval_node(&cost, (Node *) expr, root); - /* Build RelOptInfo */ - rel = build_simple_rel(root, 1, NULL); + /* + * We arbitrarily define "expensive" as "more than 10X + * cpu_operator_cost". Note this will take in any PL function + * with default cost. + */ + if (cost.per_tuple > 10 * cpu_operator_cost) + { + postpone_col[i] = true; + have_expensive = true; + } + } + } + else + { + /* For sortgroupref cols, just check if any contain SRFs */ + if (!have_srf_sortcols && + parse->hasTargetSRFs && + expression_returns_set((Node *) expr)) + have_srf_sortcols = true; + } - /* Locate IndexOptInfo for the target index */ - indexInfo = NULL; - foreach(lc, rel->indexlist) - { - indexInfo = lfirst_node(IndexOptInfo, lc); - if (indexInfo->indexoid == indexOid) - break; + i++; } /* - * It's possible that get_relation_info did not generate an IndexOptInfo - * for the desired index; this could happen if it's not yet reached its - * indcheckxmin usability horizon, or if it's a system index and we're - * ignoring system indexes. In such cases we should tell CLUSTER to not - * trust the index contents but use seqscan-and-sort. + * We can postpone SRFs if we have some but none are in sortgroupref cols. */ - if (lc == NULL) /* not in the list? */ - return true; /* use sort */ + postpone_srfs = (have_srf && !have_srf_sortcols); /* - * Rather than doing all the pushups that would be needed to use - * set_baserel_size_estimates, just do a quick hack for rows and width. + * If we don't need a post-sort projection, just return final_target. */ - rel->rows = rel->tuples; - rel->reltarget->width = get_relation_data_width(tableOid, NULL); + if (!(postpone_srfs || have_volatile || + (have_expensive && + (parse->limitCount || root->tuple_fraction > 0)))) + return final_target; - root->total_table_pages = rel->pages; + /* + * Report whether the post-sort projection will contain set-returning + * functions. This is important because it affects whether the Sort can + * rely on the query's LIMIT (if any) to bound the number of rows it needs + * to return. + */ + *have_postponed_srfs = postpone_srfs; /* - * Determine eval cost of the index expressions, if any. We need to - * charge twice that amount for each tuple comparison that happens during - * the sort, since tuplesort.c will have to re-evaluate the index - * expressions each time. (XXX that's pretty inefficient...) + * Construct the sort-input target, taking all non-postponable columns and + * then adding Vars, PlaceHolderVars, Aggrefs, and WindowFuncs found in + * the postponable ones. */ - cost_qual_eval(&indexExprCost, indexInfo->indexprs, root); - comparisonCost = 2.0 * (indexExprCost.startup + indexExprCost.per_tuple); + input_target = create_empty_pathtarget(); + postponable_cols = NIL; - /* Estimate the cost of seq scan + sort */ - seqScanPath = create_seqscan_path(root, rel, NULL, 0); - cost_sort(&seqScanAndSortPath, root, NIL, - seqScanPath->total_cost, rel->tuples, rel->reltarget->width, - comparisonCost, maintenance_work_mem, -1.0); + i = 0; + foreach(lc, final_target->exprs) + { + Expr *expr = (Expr *) lfirst(lc); - /* Estimate the cost of index scan */ - indexScanPath = create_index_path(root, indexInfo, - NIL, NIL, NIL, NIL, NIL, - ForwardScanDirection, false, - NULL, 1.0, false); + if (postpone_col[i] || (postpone_srfs && col_is_srf[i])) + postponable_cols = lappend(postponable_cols, expr); + else + add_column_to_pathtarget(input_target, expr, + get_pathtarget_sortgroupref(final_target, i)); - return (seqScanAndSortPath.total_cost < indexScanPath->path.total_cost); + i++; + } + + /* + * Pull out all the Vars, Aggrefs, and WindowFuncs mentioned in + * postponable columns, and add them to the sort-input target if not + * already present. (Some might be there already.) We mustn't + * deconstruct Aggrefs or WindowFuncs here, since the projection node + * would be unable to recompute them. + */ + postponable_vars = pull_var_clause((Node *) postponable_cols, + PVC_INCLUDE_AGGREGATES | + PVC_INCLUDE_WINDOWFUNCS | + PVC_INCLUDE_PLACEHOLDERS); + add_new_columns_to_pathtarget(input_target, postponable_vars); + + /* clean up cruft */ + list_free(postponable_vars); + list_free(postponable_cols); + + /* XXX this represents even more redundant cost calculation ... */ + return set_pathtarget_cost_width(root, input_target); } /* - * plan_create_index_workers - * Use the planner to decide how many parallel worker processes - * CREATE INDEX should request for use - * - * tableOid is the table on which the index is to be built. indexOid is the - * OID of an index to be created or reindexed (which must be a btree index). + * get_cheapest_fractional_path + * Find the cheapest path for retrieving a specified fraction of all + * the tuples expected to be returned by the given relation. * - * Return value is the number of parallel worker processes to request. It - * may be unsafe to proceed if this is 0. Note that this does not include the - * leader participating as a worker (value is always a number of parallel - * worker processes). + * We interpret tuple_fraction the same way as grouping_planner. * - * Note: caller had better already hold some type of lock on the table and - * index. + * We assume set_cheapest() has been run on the given rel. */ -int -plan_create_index_workers(Oid tableOid, Oid indexOid) +Path * +get_cheapest_fractional_path(RelOptInfo *rel, double tuple_fraction) { - PlannerInfo *root; - Query *query; - PlannerGlobal *glob; - RangeTblEntry *rte; - Relation heap; - Relation index; - RelOptInfo *rel; - int parallel_workers; - BlockNumber heap_blocks; - double reltuples; - double allvisfrac; - - /* Return immediately when parallelism disabled */ - if (dynamic_shared_memory_type == DSM_IMPL_NONE || - max_parallel_maintenance_workers == 0) - return 0; - - /* Set up largely-dummy planner state */ - query = makeNode(Query); - query->commandType = CMD_SELECT; - - glob = makeNode(PlannerGlobal); - - root = makeNode(PlannerInfo); - root->parse = query; - root->glob = glob; - root->query_level = 1; - root->planner_cxt = CurrentMemoryContext; - root->wt_param_id = -1; - - /* - * Build a minimal RTE. - * - * Set the target's table to be an inheritance parent. This is a kludge - * that prevents problems within get_relation_info(), which does not - * expect that any IndexOptInfo is currently undergoing REINDEX. - */ - rte = makeNode(RangeTblEntry); - rte->rtekind = RTE_RELATION; - rte->relid = tableOid; - rte->relkind = RELKIND_RELATION; /* Don't be too picky. */ - rte->lateral = false; - rte->inh = true; - rte->inFromCl = true; - query->rtable = list_make1(rte); - - /* Set up RTE/RelOptInfo arrays */ - setup_simple_rel_arrays(root); - - /* Build RelOptInfo */ - rel = build_simple_rel(root, 1, NULL); + Path *best_path = rel->cheapest_total_path; + ListCell *l; - heap = heap_open(tableOid, NoLock); - index = index_open(indexOid, NoLock); + /* If all tuples will be retrieved, just return the cheapest-total path */ + if (tuple_fraction <= 0.0) + return best_path; - /* - * Determine if it's safe to proceed. - * - * Currently, parallel workers can't access the leader's temporary tables. - * Furthermore, any index predicate or index expressions must be parallel - * safe. - */ - if (heap->rd_rel->relpersistence == RELPERSISTENCE_TEMP || - !is_parallel_safe(root, (Node *) RelationGetIndexExpressions(index)) || - !is_parallel_safe(root, (Node *) RelationGetIndexPredicate(index))) - { - parallel_workers = 0; - goto done; - } + /* Convert absolute # of tuples to a fraction; no need to clamp to 0..1 */ + if (tuple_fraction >= 1.0 && best_path->rows > 0) + tuple_fraction /= best_path->rows; - /* - * If parallel_workers storage parameter is set for the table, accept that - * as the number of parallel worker processes to launch (though still cap - * at max_parallel_maintenance_workers). Note that we deliberately do not - * consider any other factor when parallel_workers is set. (e.g., memory - * use by workers.) - */ - if (rel->rel_parallel_workers != -1) + foreach(l, rel->pathlist) { - parallel_workers = Min(rel->rel_parallel_workers, - max_parallel_maintenance_workers); - goto done; - } - - /* - * Estimate heap relation size ourselves, since rel->pages cannot be - * trusted (heap RTE was marked as inheritance parent) - */ - estimate_rel_size(heap, NULL, &heap_blocks, &reltuples, &allvisfrac); - - /* - * Determine number of workers to scan the heap relation using generic - * model - */ - parallel_workers = compute_parallel_worker(rel, heap_blocks, -1, - max_parallel_maintenance_workers); + Path *path = (Path *) lfirst(l); - /* - * Cap workers based on available maintenance_work_mem as needed. - * - * Note that each tuplesort participant receives an even share of the - * total maintenance_work_mem budget. Aim to leave participants - * (including the leader as a participant) with no less than 32MB of - * memory. This leaves cases where maintenance_work_mem is set to 64MB - * immediately past the threshold of being capable of launching a single - * parallel worker to sort. - */ - while (parallel_workers > 0 && - maintenance_work_mem / (parallel_workers + 1) < 32768L) - parallel_workers--; + if (path == rel->cheapest_total_path || + compare_fractional_path_costs(best_path, path, tuple_fraction) <= 0) + continue; -done: - index_close(index, NoLock); - heap_close(heap, NoLock); + best_path = path; + } - return parallel_workers; + return best_path; } /* - * add_paths_to_grouping_rel + * adjust_paths_for_srfs + * Fix up the Paths of the given upperrel to handle tSRFs properly. + * + * The executor can only handle set-returning functions that appear at the + * top level of the targetlist of a ProjectSet plan node. If we have any SRFs + * that are not at top level, we need to split up the evaluation into multiple + * plan levels in which each level satisfies this constraint. This function + * modifies each Path of an upperrel that (might) compute any SRFs in its + * output tlist to insert appropriate projection steps. * - * Add non-partial paths to grouping relation. + * The given targets and targets_contain_srfs lists are from + * split_pathtarget_at_srfs(). We assume the existing Paths emit the first + * target in targets. */ static void -add_paths_to_grouping_rel(PlannerInfo *root, RelOptInfo *input_rel, - RelOptInfo *grouped_rel, - RelOptInfo *partially_grouped_rel, - const AggClauseCosts *agg_costs, - grouping_sets_data *gd, double dNumGroups, - GroupPathExtraData *extra) +adjust_paths_for_srfs(PlannerInfo *root, RelOptInfo *rel, + List *targets, List *targets_contain_srfs) { - Query *parse = root->parse; - Path *cheapest_path = input_rel->cheapest_total_path; ListCell *lc; - bool can_hash = (extra->flags & GROUPING_CAN_USE_HASH) != 0; - bool can_sort = (extra->flags & GROUPING_CAN_USE_SORT) != 0; - List *havingQual = (List *) extra->havingQual; - AggClauseCosts *agg_final_costs = &extra->agg_final_costs; - if (can_sort) - { - /* - * Use any available suitably-sorted path as input, and also consider - * sorting the cheapest-total path. - */ - foreach(lc, input_rel->pathlist) - { - Path *path = (Path *) lfirst(lc); - bool is_sorted; + Assert(list_length(targets) == list_length(targets_contain_srfs)); + Assert(!linitial_int(targets_contain_srfs)); - is_sorted = pathkeys_contained_in(root->group_pathkeys, - path->pathkeys); - if (path == cheapest_path || is_sorted) - { - /* Sort the cheapest-total path if it isn't already sorted */ - if (!is_sorted) - path = (Path *) create_sort_path(root, - grouped_rel, - path, - root->group_pathkeys, - -1.0); - - /* Now decide what to stick atop it */ - if (parse->groupingSets) - { - consider_groupingsets_paths(root, grouped_rel, - path, true, can_hash, - gd, agg_costs, dNumGroups); - } - else if (parse->hasAggs) - { - /* - * We have aggregation, possibly with plain GROUP BY. Make - * an AggPath. - */ - add_path(grouped_rel, (Path *) - create_agg_path(root, - grouped_rel, - path, - grouped_rel->reltarget, - parse->groupClause ? AGG_SORTED : AGG_PLAIN, - AGGSPLIT_SIMPLE, - parse->groupClause, - havingQual, - agg_costs, - dNumGroups)); - } - else if (parse->groupClause) - { - /* - * We have GROUP BY without aggregation or grouping sets. - * Make a GroupPath. - */ - add_path(grouped_rel, (Path *) - create_group_path(root, - grouped_rel, - path, - parse->groupClause, - havingQual, - dNumGroups)); - } - else - { - /* Other cases should have been handled above */ - Assert(false); - } - } - } + /* If no SRFs appear at this plan level, nothing to do */ + if (list_length(targets) == 1) + return; - /* - * Instead of operating directly on the input relation, we can - * consider finalizing a partially aggregated path. - */ - if (partially_grouped_rel != NULL) - { - foreach(lc, partially_grouped_rel->pathlist) - { - Path *path = (Path *) lfirst(lc); + /* + * Stack SRF-evaluation nodes atop each path for the rel. + * + * In principle we should re-run set_cheapest() here to identify the + * cheapest path, but it seems unlikely that adding the same tlist eval + * costs to all the paths would change that, so we don't bother. Instead, + * just assume that the cheapest-startup and cheapest-total paths remain + * so. (There should be no parameterized paths anymore, so we needn't + * worry about updating cheapest_parameterized_paths.) + */ + foreach(lc, rel->pathlist) + { + Path *subpath = (Path *) lfirst(lc); + Path *newpath = subpath; + ListCell *lc1, + *lc2; - /* - * Insert a Sort node, if required. But there's no point in - * sorting anything but the cheapest path. - */ - if (!pathkeys_contained_in(root->group_pathkeys, path->pathkeys)) - { - if (path != partially_grouped_rel->cheapest_total_path) - continue; - path = (Path *) create_sort_path(root, - grouped_rel, - path, - root->group_pathkeys, - -1.0); - } + Assert(subpath->param_info == NULL); + forboth(lc1, targets, lc2, targets_contain_srfs) + { + PathTarget *thistarget = lfirst_node(PathTarget, lc1); + bool contains_srfs = (bool) lfirst_int(lc2); - if (parse->hasAggs) - add_path(grouped_rel, (Path *) - create_agg_path(root, - grouped_rel, - path, - grouped_rel->reltarget, - parse->groupClause ? AGG_SORTED : AGG_PLAIN, - AGGSPLIT_FINAL_DESERIAL, - parse->groupClause, - havingQual, - agg_final_costs, - dNumGroups)); - else - add_path(grouped_rel, (Path *) - create_group_path(root, - grouped_rel, - path, - parse->groupClause, - havingQual, - dNumGroups)); - } + /* If this level doesn't contain SRFs, do regular projection */ + if (contains_srfs) + newpath = (Path *) create_set_projection_path(root, + rel, + newpath, + thistarget); + else + newpath = (Path *) apply_projection_to_path(root, + rel, + newpath, + thistarget); } + lfirst(lc) = newpath; + if (subpath == rel->cheapest_startup_path) + rel->cheapest_startup_path = newpath; + if (subpath == rel->cheapest_total_path) + rel->cheapest_total_path = newpath; } - if (can_hash) + /* Likewise for partial paths, if any */ + foreach(lc, rel->partial_pathlist) { - Size hashaggtablesize; + Path *subpath = (Path *) lfirst(lc); + Path *newpath = subpath; + ListCell *lc1, + *lc2; - if (parse->groupingSets) - { - /* - * Try for a hash-only groupingsets path over unsorted input. - */ - consider_groupingsets_paths(root, grouped_rel, - cheapest_path, false, true, - gd, agg_costs, dNumGroups); - } - else + Assert(subpath->param_info == NULL); + forboth(lc1, targets, lc2, targets_contain_srfs) { - hashaggtablesize = estimate_hashagg_tablesize(cheapest_path, - agg_costs, - dNumGroups); + PathTarget *thistarget = lfirst_node(PathTarget, lc1); + bool contains_srfs = (bool) lfirst_int(lc2); - /* - * Provided that the estimated size of the hashtable does not - * exceed work_mem, we'll generate a HashAgg Path, although if we - * were unable to sort above, then we'd better generate a Path, so - * that we at least have one. - */ - if (hashaggtablesize < work_mem * 1024L || - grouped_rel->pathlist == NIL) + /* If this level doesn't contain SRFs, do regular projection */ + if (contains_srfs) + newpath = (Path *) create_set_projection_path(root, + rel, + newpath, + thistarget); + else { - /* - * We just need an Agg over the cheapest-total input path, - * since input order won't matter. - */ - add_path(grouped_rel, (Path *) - create_agg_path(root, grouped_rel, - cheapest_path, - grouped_rel->reltarget, - AGG_HASHED, - AGGSPLIT_SIMPLE, - parse->groupClause, - havingQual, - agg_costs, - dNumGroups)); + /* avoid apply_projection_to_path, in case of multiple refs */ + newpath = (Path *) create_projection_path(root, + rel, + newpath, + thistarget); } } - - /* - * Generate a Finalize HashAgg Path atop of the cheapest partially - * grouped path, assuming there is one. Once again, we'll only do this - * if it looks as though the hash table won't exceed work_mem. - */ - if (partially_grouped_rel && partially_grouped_rel->pathlist) - { - Path *path = partially_grouped_rel->cheapest_total_path; - - hashaggtablesize = estimate_hashagg_tablesize(path, - agg_final_costs, - dNumGroups); - - if (hashaggtablesize < work_mem * 1024L) - add_path(grouped_rel, (Path *) - create_agg_path(root, - grouped_rel, - path, - grouped_rel->reltarget, - AGG_HASHED, - AGGSPLIT_FINAL_DESERIAL, - parse->groupClause, - havingQual, - agg_final_costs, - dNumGroups)); - } + lfirst(lc) = newpath; } - - /* - * When partitionwise aggregate is used, we might have fully aggregated - * paths in the partial pathlist, because add_paths_to_append_rel() will - * consider a path for grouped_rel consisting of a Parallel Append of - * non-partial paths from each child. - */ - if (grouped_rel->partial_pathlist != NIL) - gather_grouping_paths(root, grouped_rel); } /* - * create_partial_grouping_paths + * expression_planner + * Perform planner's transformations on a standalone expression. * - * Create a new upper relation representing the result of partial aggregation - * and populate it with appropriate paths. Note that we don't finalize the - * lists of paths here, so the caller can add additional partial or non-partial - * paths and must afterward call gather_grouping_paths and set_cheapest on - * the returned upper relation. + * Various utility commands need to evaluate expressions that are not part + * of a plannable query. They can do so using the executor's regular + * expression-execution machinery, but first the expression has to be fed + * through here to transform it from parser output to something executable. * - * All paths for this new upper relation -- both partial and non-partial -- - * have been partially aggregated but require a subsequent FinalizeAggregate - * step. + * Currently, we disallow sublinks in standalone expressions, so there's no + * real "planning" involved here. (That might not always be true though.) + * What we must do is run eval_const_expressions to ensure that any function + * calls are converted to positional notation and function default arguments + * get inserted. The fact that constant subexpressions get simplified is a + * side-effect that is useful when the expression will get evaluated more than + * once. Also, we must fix operator function IDs. * - * NB: This function is allowed to return NULL if it determines that there is - * no real need to create a new RelOptInfo. + * Note: this must not make any damaging changes to the passed-in expression + * tree. (It would actually be okay to apply fix_opfuncids to it, but since + * we first do an expression_tree_mutator-based walk, what is returned will + * be a new node tree.) */ -static RelOptInfo * -create_partial_grouping_paths(PlannerInfo *root, - RelOptInfo *grouped_rel, - RelOptInfo *input_rel, - grouping_sets_data *gd, - GroupPathExtraData *extra, - bool force_rel_creation) +Expr * +expression_planner(Expr *expr) { - Query *parse = root->parse; - RelOptInfo *partially_grouped_rel; - AggClauseCosts *agg_partial_costs = &extra->agg_partial_costs; - AggClauseCosts *agg_final_costs = &extra->agg_final_costs; - Path *cheapest_partial_path = NULL; - Path *cheapest_total_path = NULL; - double dNumPartialGroups = 0; - double dNumPartialPartialGroups = 0; - ListCell *lc; - bool can_hash = (extra->flags & GROUPING_CAN_USE_HASH) != 0; - bool can_sort = (extra->flags & GROUPING_CAN_USE_SORT) != 0; - - /* - * Consider whether we should generate partially aggregated non-partial - * paths. We can only do this if we have a non-partial path, and only if - * the parent of the input rel is performing partial partitionwise - * aggregation. (Note that extra->patype is the type of partitionwise - * aggregation being used at the parent level, not this level.) - */ - if (input_rel->pathlist != NIL && - extra->patype == PARTITIONWISE_AGGREGATE_PARTIAL) - cheapest_total_path = input_rel->cheapest_total_path; - - /* - * If parallelism is possible for grouped_rel, then we should consider - * generating partially-grouped partial paths. However, if the input rel - * has no partial paths, then we can't. - */ - if (grouped_rel->consider_parallel && input_rel->partial_pathlist != NIL) - cheapest_partial_path = linitial(input_rel->partial_pathlist); - - /* - * If we can't partially aggregate partial paths, and we can't partially - * aggregate non-partial paths, then don't bother creating the new - * RelOptInfo at all, unless the caller specified force_rel_creation. - */ - if (cheapest_total_path == NULL && - cheapest_partial_path == NULL && - !force_rel_creation) - return NULL; - - /* - * Build a new upper relation to represent the result of partially - * aggregating the rows from the input relation. - */ - partially_grouped_rel = fetch_upper_rel(root, - UPPERREL_PARTIAL_GROUP_AGG, - grouped_rel->relids); - partially_grouped_rel->consider_parallel = - grouped_rel->consider_parallel; - partially_grouped_rel->reloptkind = grouped_rel->reloptkind; - partially_grouped_rel->serverid = grouped_rel->serverid; - partially_grouped_rel->userid = grouped_rel->userid; - partially_grouped_rel->useridiscurrent = grouped_rel->useridiscurrent; - partially_grouped_rel->fdwroutine = grouped_rel->fdwroutine; + Node *result; /* - * Build target list for partial aggregate paths. These paths cannot just - * emit the same tlist as regular aggregate paths, because (1) we must - * include Vars and Aggrefs needed in HAVING, which might not appear in - * the result tlist, and (2) the Aggrefs must be set in partial mode. + * Convert named-argument function calls, insert default arguments and + * simplify constant subexprs */ - partially_grouped_rel->reltarget = - make_partial_grouping_target(root, grouped_rel->reltarget, - extra->havingQual); + result = eval_const_expressions(NULL, (Node *) expr); - if (!extra->partial_costs_set) - { - /* - * Collect statistics about aggregates for estimating costs of - * performing aggregation in parallel. - */ - MemSet(agg_partial_costs, 0, sizeof(AggClauseCosts)); - MemSet(agg_final_costs, 0, sizeof(AggClauseCosts)); - if (parse->hasAggs) - { - List *partial_target_exprs; - - /* partial phase */ - partial_target_exprs = partially_grouped_rel->reltarget->exprs; - get_agg_clause_costs(root, (Node *) partial_target_exprs, - AGGSPLIT_INITIAL_SERIAL, - agg_partial_costs); - - /* final phase */ - get_agg_clause_costs(root, (Node *) grouped_rel->reltarget->exprs, - AGGSPLIT_FINAL_DESERIAL, - agg_final_costs); - get_agg_clause_costs(root, extra->havingQual, - AGGSPLIT_FINAL_DESERIAL, - agg_final_costs); - } + /* Fill in opfuncid values if missing */ + fix_opfuncids(result); - extra->partial_costs_set = true; - } + return (Expr *) result; +} - /* Estimate number of partial groups. */ - if (cheapest_total_path != NULL) - dNumPartialGroups = - get_number_of_groups(root, - cheapest_total_path->rows, - gd, - extra->targetList); - if (cheapest_partial_path != NULL) - dNumPartialPartialGroups = - get_number_of_groups(root, - cheapest_partial_path->rows, - gd, - extra->targetList); - - if (can_sort && cheapest_total_path != NULL) - { - /* This should have been checked previously */ - Assert(parse->hasAggs || parse->groupClause); - /* - * Use any available suitably-sorted path as input, and also consider - * sorting the cheapest partial path. - */ - foreach(lc, input_rel->pathlist) - { - Path *path = (Path *) lfirst(lc); - bool is_sorted; +/* + * plan_cluster_use_sort + * Use the planner to decide how CLUSTER should implement sorting + * + * tableOid is the OID of a table to be clustered on its index indexOid + * (which is already known to be a btree index). Decide whether it's + * cheaper to do an indexscan or a seqscan-plus-sort to execute the CLUSTER. + * Return true to use sorting, false to use an indexscan. + * + * Note: caller had better already hold some type of lock on the table. + */ +bool +plan_cluster_use_sort(Oid tableOid, Oid indexOid) +{ + PlannerInfo *root; + Query *query; + PlannerGlobal *glob; + RangeTblEntry *rte; + RelOptInfo *rel; + IndexOptInfo *indexInfo; + QualCost indexExprCost; + Cost comparisonCost; + Path *seqScanPath; + Path seqScanAndSortPath; + IndexPath *indexScanPath; + ListCell *lc; - is_sorted = pathkeys_contained_in(root->group_pathkeys, - path->pathkeys); - if (path == cheapest_total_path || is_sorted) - { - /* Sort the cheapest partial path, if it isn't already */ - if (!is_sorted) - path = (Path *) create_sort_path(root, - partially_grouped_rel, - path, - root->group_pathkeys, - -1.0); - - if (parse->hasAggs) - add_path(partially_grouped_rel, (Path *) - create_agg_path(root, - partially_grouped_rel, - path, - partially_grouped_rel->reltarget, - parse->groupClause ? AGG_SORTED : AGG_PLAIN, - AGGSPLIT_INITIAL_SERIAL, - parse->groupClause, - NIL, - agg_partial_costs, - dNumPartialGroups)); - else - add_path(partially_grouped_rel, (Path *) - create_group_path(root, - partially_grouped_rel, - path, - parse->groupClause, - NIL, - dNumPartialGroups)); - } - } - } + /* We can short-circuit the cost comparison if indexscans are disabled */ + if (!enable_indexscan) + return true; /* use sort */ - if (can_sort && cheapest_partial_path != NULL) - { - /* Similar to above logic, but for partial paths. */ - foreach(lc, input_rel->partial_pathlist) - { - Path *path = (Path *) lfirst(lc); - bool is_sorted; + /* Set up mostly-dummy planner state */ + query = makeNode(Query); + query->commandType = CMD_SELECT; - is_sorted = pathkeys_contained_in(root->group_pathkeys, - path->pathkeys); - if (path == cheapest_partial_path || is_sorted) - { - /* Sort the cheapest partial path, if it isn't already */ - if (!is_sorted) - path = (Path *) create_sort_path(root, - partially_grouped_rel, - path, - root->group_pathkeys, - -1.0); - - if (parse->hasAggs) - add_partial_path(partially_grouped_rel, (Path *) - create_agg_path(root, - partially_grouped_rel, - path, - partially_grouped_rel->reltarget, - parse->groupClause ? AGG_SORTED : AGG_PLAIN, - AGGSPLIT_INITIAL_SERIAL, - parse->groupClause, - NIL, - agg_partial_costs, - dNumPartialPartialGroups)); - else - add_partial_path(partially_grouped_rel, (Path *) - create_group_path(root, - partially_grouped_rel, - path, - parse->groupClause, - NIL, - dNumPartialPartialGroups)); - } - } - } + glob = makeNode(PlannerGlobal); - if (can_hash && cheapest_total_path != NULL) - { - Size hashaggtablesize; + root = makeNode(PlannerInfo); + root->parse = query; + root->glob = glob; + root->query_level = 1; + root->planner_cxt = CurrentMemoryContext; + root->wt_param_id = -1; - /* Checked above */ - Assert(parse->hasAggs || parse->groupClause); + /* Build a minimal RTE for the rel */ + rte = makeNode(RangeTblEntry); + rte->rtekind = RTE_RELATION; + rte->relid = tableOid; + rte->relkind = RELKIND_RELATION; /* Don't be too picky. */ + rte->lateral = false; + rte->inh = false; + rte->inFromCl = true; + query->rtable = list_make1(rte); - hashaggtablesize = - estimate_hashagg_tablesize(cheapest_total_path, - agg_partial_costs, - dNumPartialGroups); + /* Set up RTE/RelOptInfo arrays */ + setup_simple_rel_arrays(root); - /* - * Tentatively produce a partial HashAgg Path, depending on if it - * looks as if the hash table will fit in work_mem. - */ - if (hashaggtablesize < work_mem * 1024L && - cheapest_total_path != NULL) - { - add_path(partially_grouped_rel, (Path *) - create_agg_path(root, - partially_grouped_rel, - cheapest_total_path, - partially_grouped_rel->reltarget, - AGG_HASHED, - AGGSPLIT_INITIAL_SERIAL, - parse->groupClause, - NIL, - agg_partial_costs, - dNumPartialGroups)); - } - } + /* Build RelOptInfo */ + rel = build_simple_rel(root, 1, NULL); - if (can_hash && cheapest_partial_path != NULL) + /* Locate IndexOptInfo for the target index */ + indexInfo = NULL; + foreach(lc, rel->indexlist) { - Size hashaggtablesize; + indexInfo = lfirst_node(IndexOptInfo, lc); + if (indexInfo->indexoid == indexOid) + break; + } + + /* + * It's possible that get_relation_info did not generate an IndexOptInfo + * for the desired index; this could happen if it's not yet reached its + * indcheckxmin usability horizon, or if it's a system index and we're + * ignoring system indexes. In such cases we should tell CLUSTER to not + * trust the index contents but use seqscan-and-sort. + */ + if (lc == NULL) /* not in the list? */ + return true; /* use sort */ - hashaggtablesize = - estimate_hashagg_tablesize(cheapest_partial_path, - agg_partial_costs, - dNumPartialPartialGroups); + /* + * Rather than doing all the pushups that would be needed to use + * set_baserel_size_estimates, just do a quick hack for rows and width. + */ + rel->rows = rel->tuples; + rel->reltarget->width = get_relation_data_width(tableOid, NULL); - /* Do the same for partial paths. */ - if (hashaggtablesize < work_mem * 1024L && - cheapest_partial_path != NULL) - { - add_partial_path(partially_grouped_rel, (Path *) - create_agg_path(root, - partially_grouped_rel, - cheapest_partial_path, - partially_grouped_rel->reltarget, - AGG_HASHED, - AGGSPLIT_INITIAL_SERIAL, - parse->groupClause, - NIL, - agg_partial_costs, - dNumPartialPartialGroups)); - } - } + root->total_table_pages = rel->pages; /* - * If there is an FDW that's responsible for all baserels of the query, - * let it consider adding partially grouped ForeignPaths. + * Determine eval cost of the index expressions, if any. We need to + * charge twice that amount for each tuple comparison that happens during + * the sort, since tuplesort.c will have to re-evaluate the index + * expressions each time. (XXX that's pretty inefficient...) */ - if (partially_grouped_rel->fdwroutine && - partially_grouped_rel->fdwroutine->GetForeignUpperPaths) - { - FdwRoutine *fdwroutine = partially_grouped_rel->fdwroutine; + cost_qual_eval(&indexExprCost, indexInfo->indexprs, root); + comparisonCost = 2.0 * (indexExprCost.startup + indexExprCost.per_tuple); - fdwroutine->GetForeignUpperPaths(root, - UPPERREL_PARTIAL_GROUP_AGG, - input_rel, partially_grouped_rel, - extra); - } + /* Estimate the cost of seq scan + sort */ + seqScanPath = create_seqscan_path(root, rel, NULL, 0); + cost_sort(&seqScanAndSortPath, root, NIL, + seqScanPath->total_cost, rel->tuples, rel->reltarget->width, + comparisonCost, maintenance_work_mem, -1.0); + + /* Estimate the cost of index scan */ + indexScanPath = create_index_path(root, indexInfo, + NIL, NIL, NIL, NIL, NIL, + ForwardScanDirection, false, + NULL, 1.0, false); - return partially_grouped_rel; + return (seqScanAndSortPath.total_cost < indexScanPath->path.total_cost); } /* - * Generate Gather and Gather Merge paths for a grouping relation or partial - * grouping relation. + * plan_create_index_workers + * Use the planner to decide how many parallel worker processes + * CREATE INDEX should request for use + * + * tableOid is the table on which the index is to be built. indexOid is the + * OID of an index to be created or reindexed (which must be a btree index). * - * generate_gather_paths does most of the work, but we also consider a special - * case: we could try sorting the data by the group_pathkeys and then applying - * Gather Merge. + * Return value is the number of parallel worker processes to request. It + * may be unsafe to proceed if this is 0. Note that this does not include the + * leader participating as a worker (value is always a number of parallel + * worker processes). * - * NB: This function shouldn't be used for anything other than a grouped or - * partially grouped relation not only because of the fact that it explicitly - * references group_pathkeys but we pass "true" as the third argument to - * generate_gather_paths(). + * Note: caller had better already hold some type of lock on the table and + * index. */ -static void -gather_grouping_paths(PlannerInfo *root, RelOptInfo *rel) +int +plan_create_index_workers(Oid tableOid, Oid indexOid) { - Path *cheapest_partial_path; + PlannerInfo *root; + Query *query; + PlannerGlobal *glob; + RangeTblEntry *rte; + Relation heap; + Relation index; + RelOptInfo *rel; + int parallel_workers; + BlockNumber heap_blocks; + double reltuples; + double allvisfrac; - /* Try Gather for unordered paths and Gather Merge for ordered ones. */ - generate_gather_paths(root, rel, true); + /* Return immediately when parallelism disabled */ + if (dynamic_shared_memory_type == DSM_IMPL_NONE || + max_parallel_maintenance_workers == 0) + return 0; - /* Try cheapest partial path + explicit Sort + Gather Merge. */ - cheapest_partial_path = linitial(rel->partial_pathlist); - if (!pathkeys_contained_in(root->group_pathkeys, - cheapest_partial_path->pathkeys)) - { - Path *path; - double total_groups; - - total_groups = - cheapest_partial_path->rows * cheapest_partial_path->parallel_workers; - path = (Path *) create_sort_path(root, rel, cheapest_partial_path, - root->group_pathkeys, - -1.0); - path = (Path *) - create_gather_merge_path(root, - rel, - path, - rel->reltarget, - root->group_pathkeys, - NULL, - &total_groups); + /* Set up largely-dummy planner state */ + query = makeNode(Query); + query->commandType = CMD_SELECT; - add_path(rel, path); - } -} + glob = makeNode(PlannerGlobal); -/* - * can_partial_agg - * - * Determines whether or not partial grouping and/or aggregation is possible. - * Returns true when possible, false otherwise. - */ -static bool -can_partial_agg(PlannerInfo *root, const AggClauseCosts *agg_costs) -{ - Query *parse = root->parse; + root = makeNode(PlannerInfo); + root->parse = query; + root->glob = glob; + root->query_level = 1; + root->planner_cxt = CurrentMemoryContext; + root->wt_param_id = -1; - if (!parse->hasAggs && parse->groupClause == NIL) - { - /* - * We don't know how to do parallel aggregation unless we have either - * some aggregates or a grouping clause. - */ - return false; - } - else if (parse->groupingSets) + /* + * Build a minimal RTE. + * + * Set the target's table to be an inheritance parent. This is a kludge + * that prevents problems within get_relation_info(), which does not + * expect that any IndexOptInfo is currently undergoing REINDEX. + */ + rte = makeNode(RangeTblEntry); + rte->rtekind = RTE_RELATION; + rte->relid = tableOid; + rte->relkind = RELKIND_RELATION; /* Don't be too picky. */ + rte->lateral = false; + rte->inh = true; + rte->inFromCl = true; + query->rtable = list_make1(rte); + + /* Set up RTE/RelOptInfo arrays */ + setup_simple_rel_arrays(root); + + /* Build RelOptInfo */ + rel = build_simple_rel(root, 1, NULL); + + heap = heap_open(tableOid, NoLock); + index = index_open(indexOid, NoLock); + + /* + * Determine if it's safe to proceed. + * + * Currently, parallel workers can't access the leader's temporary tables. + * Furthermore, any index predicate or index expressions must be parallel + * safe. + */ + if (heap->rd_rel->relpersistence == RELPERSISTENCE_TEMP || + !is_parallel_safe(root, (Node *) RelationGetIndexExpressions(index)) || + !is_parallel_safe(root, (Node *) RelationGetIndexPredicate(index))) { - /* We don't know how to do grouping sets in parallel. */ - return false; + parallel_workers = 0; + goto done; } - else if (agg_costs->hasNonPartial || agg_costs->hasNonSerial) + + /* + * If parallel_workers storage parameter is set for the table, accept that + * as the number of parallel worker processes to launch (though still cap + * at max_parallel_maintenance_workers). Note that we deliberately do not + * consider any other factor when parallel_workers is set. (e.g., memory + * use by workers.) + */ + if (rel->rel_parallel_workers != -1) { - /* Insufficient support for partial mode. */ - return false; + parallel_workers = Min(rel->rel_parallel_workers, + max_parallel_maintenance_workers); + goto done; } - /* Everything looks good. */ - return true; + /* + * Estimate heap relation size ourselves, since rel->pages cannot be + * trusted (heap RTE was marked as inheritance parent) + */ + estimate_rel_size(heap, NULL, &heap_blocks, &reltuples, &allvisfrac); + + /* + * Determine number of workers to scan the heap relation using generic + * model + */ + parallel_workers = compute_parallel_worker(rel, heap_blocks, -1, + max_parallel_maintenance_workers); + + /* + * Cap workers based on available maintenance_work_mem as needed. + * + * Note that each tuplesort participant receives an even share of the + * total maintenance_work_mem budget. Aim to leave participants + * (including the leader as a participant) with no less than 32MB of + * memory. This leaves cases where maintenance_work_mem is set to 64MB + * immediately past the threshold of being capable of launching a single + * parallel worker to sort. + */ + while (parallel_workers > 0 && + maintenance_work_mem / (parallel_workers + 1) < 32768L) + parallel_workers--; + +done: + index_close(index, NoLock); + heap_close(heap, NoLock); + + return parallel_workers; } /* @@ -6980,208 +5235,3 @@ apply_scanjoin_target_to_paths(PlannerInfo *root, */ set_cheapest(rel); } - -/* - * create_partitionwise_grouping_paths - * - * If the partition keys of input relation are part of the GROUP BY clause, all - * the rows belonging to a given group come from a single partition. This - * allows aggregation/grouping over a partitioned relation to be broken down - * into aggregation/grouping on each partition. This should be no worse, and - * often better, than the normal approach. - * - * However, if the GROUP BY clause does not contain all the partition keys, - * rows from a given group may be spread across multiple partitions. In that - * case, we perform partial aggregation for each group, append the results, - * and then finalize aggregation. This is less certain to win than the - * previous case. It may win if the PartialAggregate stage greatly reduces - * the number of groups, because fewer rows will pass through the Append node. - * It may lose if we have lots of small groups. - */ -static void -create_partitionwise_grouping_paths(PlannerInfo *root, - RelOptInfo *input_rel, - RelOptInfo *grouped_rel, - RelOptInfo *partially_grouped_rel, - const AggClauseCosts *agg_costs, - grouping_sets_data *gd, - PartitionwiseAggregateType patype, - GroupPathExtraData *extra) -{ - int nparts = input_rel->nparts; - int cnt_parts; - List *grouped_live_children = NIL; - List *partially_grouped_live_children = NIL; - PathTarget *target = grouped_rel->reltarget; - - Assert(patype != PARTITIONWISE_AGGREGATE_NONE); - Assert(patype != PARTITIONWISE_AGGREGATE_PARTIAL || - partially_grouped_rel != NULL); - - /* Add paths for partitionwise aggregation/grouping. */ - for (cnt_parts = 0; cnt_parts < nparts; cnt_parts++) - { - RelOptInfo *child_input_rel = input_rel->part_rels[cnt_parts]; - PathTarget *child_target = copy_pathtarget(target); - AppendRelInfo **appinfos; - int nappinfos; - GroupPathExtraData child_extra; - RelOptInfo *child_grouped_rel; - RelOptInfo *child_partially_grouped_rel; - - /* Input child rel must have a path */ - Assert(child_input_rel->pathlist != NIL); - - /* - * Copy the given "extra" structure as is and then override the - * members specific to this child. - */ - memcpy(&child_extra, extra, sizeof(child_extra)); - - appinfos = find_appinfos_by_relids(root, child_input_rel->relids, - &nappinfos); - - child_target->exprs = (List *) - adjust_appendrel_attrs(root, - (Node *) target->exprs, - nappinfos, appinfos); - - /* Translate havingQual and targetList. */ - child_extra.havingQual = (Node *) - adjust_appendrel_attrs(root, - extra->havingQual, - nappinfos, appinfos); - child_extra.targetList = (List *) - adjust_appendrel_attrs(root, - (Node *) extra->targetList, - nappinfos, appinfos); - - /* - * extra->patype was the value computed for our parent rel; patype is - * the value for this relation. For the child, our value is its - * parent rel's value. - */ - child_extra.patype = patype; - - /* - * Create grouping relation to hold fully aggregated grouping and/or - * aggregation paths for the child. - */ - child_grouped_rel = make_grouping_rel(root, child_input_rel, - child_target, - extra->target_parallel_safe, - child_extra.havingQual); - - /* Ignore empty children. They contribute nothing. */ - if (IS_DUMMY_REL(child_input_rel)) - { - mark_dummy_rel(child_grouped_rel); - - continue; - } - - /* Create grouping paths for this child relation. */ - create_ordinary_grouping_paths(root, child_input_rel, - child_grouped_rel, - agg_costs, gd, &child_extra, - &child_partially_grouped_rel); - - if (child_partially_grouped_rel) - { - partially_grouped_live_children = - lappend(partially_grouped_live_children, - child_partially_grouped_rel); - } - - if (patype == PARTITIONWISE_AGGREGATE_FULL) - { - set_cheapest(child_grouped_rel); - grouped_live_children = lappend(grouped_live_children, - child_grouped_rel); - } - - pfree(appinfos); - } - - /* - * All children can't be dummy at this point. If they are, then the parent - * too marked as dummy. - */ - Assert(grouped_live_children != NIL || - partially_grouped_live_children != NIL); - - /* - * Try to create append paths for partially grouped children. For full - * partitionwise aggregation, we might have paths in the partial_pathlist - * if parallel aggregation is possible. For partial partitionwise - * aggregation, we may have paths in both pathlist and partial_pathlist. - */ - if (partially_grouped_rel) - { - add_paths_to_append_rel(root, partially_grouped_rel, - partially_grouped_live_children); - - /* - * We need call set_cheapest, since the finalization step will use the - * cheapest path from the rel. - */ - if (partially_grouped_rel->pathlist) - set_cheapest(partially_grouped_rel); - } - - /* If possible, create append paths for fully grouped children. */ - if (patype == PARTITIONWISE_AGGREGATE_FULL) - add_paths_to_append_rel(root, grouped_rel, grouped_live_children); -} - -/* - * group_by_has_partkey - * - * Returns true, if all the partition keys of the given relation are part of - * the GROUP BY clauses, false otherwise. - */ -static bool -group_by_has_partkey(RelOptInfo *input_rel, - List *targetList, - List *groupClause) -{ - List *groupexprs = get_sortgrouplist_exprs(groupClause, targetList); - int cnt = 0; - int partnatts; - - /* Input relation should be partitioned. */ - Assert(input_rel->part_scheme); - - /* Rule out early, if there are no partition keys present. */ - if (!input_rel->partexprs) - return false; - - partnatts = input_rel->part_scheme->partnatts; - - for (cnt = 0; cnt < partnatts; cnt++) - { - List *partexprs = input_rel->partexprs[cnt]; - ListCell *lc; - bool found = false; - - foreach(lc, partexprs) - { - Expr *partexpr = lfirst(lc); - - if (list_member(groupexprs, partexpr)) - { - found = true; - break; - } - } - - /* - * If none of the partition key expressions match with any of the - * GROUP BY expression, return false. - */ - if (!found) - return false; - } - - return true; -} diff --git a/src/include/nodes/relation.h b/src/include/nodes/relation.h index 6bf9e84c4a..ad77416050 100644 --- a/src/include/nodes/relation.h +++ b/src/include/nodes/relation.h @@ -2424,4 +2424,23 @@ typedef struct JoinCostWorkspace double inner_rows_total; } JoinCostWorkspace; + + +/* + * Data specific to grouping sets + */ + +typedef struct +{ + List *rollups; + List *hash_sets_idx; + double dNumHashGroups; + bool any_hashable; + Bitmapset *unsortable_refs; + Bitmapset *unhashable_refs; + List *unsortable_sets; + int *tleref_to_colnum_map; +} grouping_sets_data; + + #endif /* RELATION_H */ diff --git a/src/include/optimizer/paths.h b/src/include/optimizer/paths.h index cafde307ad..89835ad259 100644 --- a/src/include/optimizer/paths.h +++ b/src/include/optimizer/paths.h @@ -120,6 +120,19 @@ extern bool have_partkey_equi_join(RelOptInfo *joinrel, JoinType jointype, List *restrictlist); /* + * aggpath.c + * routines to create grouping paths + */ +extern RelOptInfo *create_grouping_paths(PlannerInfo *root, + RelOptInfo *input_rel, + PathTarget *target, + bool target_parallel_safe, + const AggClauseCosts *agg_costs, + grouping_sets_data *gd); +extern List *remap_to_groupclause_idx(List *groupClause, List *gsets, + int *tleref_to_colnum_map); + +/* * equivclass.c * routines for managing EquivalenceClasses */ diff --git a/src/include/optimizer/planmain.h b/src/include/optimizer/planmain.h index 4e61dff241..dd6e912373 100644 --- a/src/include/optimizer/planmain.h +++ b/src/include/optimizer/planmain.h @@ -42,6 +42,7 @@ extern RelOptInfo *query_planner(PlannerInfo *root); */ extern void preprocess_minmax_aggregates(PlannerInfo *root, List *tlist); + /* * prototypes for plan/createplan.c */ diff --git a/src/include/optimizer/planner.h b/src/include/optimizer/planner.h index c090396e13..497a8c0581 100644 --- a/src/include/optimizer/planner.h +++ b/src/include/optimizer/planner.h @@ -55,6 +55,8 @@ extern Path *get_cheapest_fractional_path(RelOptInfo *rel, extern Expr *expression_planner(Expr *expr); extern Expr *preprocess_phv_expression(PlannerInfo *root, Expr *expr); +extern List *preprocess_groupclause(PlannerInfo *root, List *force); +extern grouping_sets_data *preprocess_grouping_sets(PlannerInfo *root); extern bool plan_cluster_use_sort(Oid tableOid, Oid indexOid); extern int plan_create_index_workers(Oid tableOid, Oid indexOid); -- 2.11.0