From 11f5d895e4efe7b3b3a7bbc58efbb4d6c40274c0 Mon Sep 17 00:00:00 2001 From: Melanie Plageman Date: Wed, 6 Sep 2023 14:57:20 -0400 Subject: [PATCH v3 1/2] Move heap_page_prune output parameters into struct Add PruneResult, a structure containing the output parameters and result of heap_page_prune(). Reorganizing the results of heap_page_prune() into a struct simplifies the function signature and provides a location for future commits to store additional output parameters. Note that heap_page_prune() no longer NULL checks off_loc, the current tuple's offset in the line pointer array. It will never be NULL now that it is a member of a required output parameter, PruneResult. Discussion: https://postgr.es/m/CAAKRu_br124qsGJieuYA0nGjywEukhK1dKBfRdby_4yY3E9SXA%40mail.gmail.com --- src/backend/access/heap/pruneheap.c | 47 +++++++++++----------------- src/backend/access/heap/vacuumlazy.c | 19 +++++------ src/include/access/heapam.h | 20 ++++++++++-- src/tools/pgindent/typedefs.list | 1 + 4 files changed, 45 insertions(+), 42 deletions(-) diff --git a/src/backend/access/heap/pruneheap.c b/src/backend/access/heap/pruneheap.c index 18193efa23..f0847795a7 100644 --- a/src/backend/access/heap/pruneheap.c +++ b/src/backend/access/heap/pruneheap.c @@ -155,15 +155,13 @@ heap_page_prune_opt(Relation relation, Buffer buffer) */ if (PageIsFull(page) || PageGetHeapFreeSpace(page) < minfree) { - int ndeleted, - nnewlpdead; + PruneResult presult; - ndeleted = heap_page_prune(relation, buffer, vistest, - &nnewlpdead, NULL); + heap_page_prune(relation, buffer, vistest, &presult); /* * Report the number of tuples reclaimed to pgstats. This is - * ndeleted minus the number of newly-LP_DEAD-set items. + * presult.ndeleted minus the number of newly-LP_DEAD-set items. * * We derive the number of dead tuples like this to avoid totally * forgetting about items that were set to LP_DEAD, since they @@ -175,9 +173,9 @@ heap_page_prune_opt(Relation relation, Buffer buffer) * tracks ndeleted, since it will set the same LP_DEAD items to * LP_UNUSED separately. */ - if (ndeleted > nnewlpdead) + if (presult.ndeleted > presult.nnewlpdead) pgstat_update_heap_dead_tuples(relation, - ndeleted - nnewlpdead); + presult.ndeleted - presult.nnewlpdead); } /* And release buffer lock */ @@ -204,21 +202,15 @@ heap_page_prune_opt(Relation relation, Buffer buffer) * (see heap_prune_satisfies_vacuum and * HeapTupleSatisfiesVacuum). * - * Sets *nnewlpdead for caller, indicating the number of items that were - * newly set LP_DEAD during prune operation. - * - * off_loc is the offset location required by the caller to use in error - * callback. - * - * Returns the number of tuples deleted from the page during this call. + * presult contains output parameters needed by callers such as the number of + * tuples removed and the number of line pointers newly marked LP_DEAD. + * heap_page_prune() is responsible for initializing it. */ -int +void heap_page_prune(Relation relation, Buffer buffer, GlobalVisState *vistest, - int *nnewlpdead, - OffsetNumber *off_loc) + PruneResult *presult) { - int ndeleted = 0; Page page = BufferGetPage(buffer); BlockNumber blockno = BufferGetBlockNumber(buffer); OffsetNumber offnum, @@ -244,6 +236,10 @@ heap_page_prune(Relation relation, Buffer buffer, prstate.nredirected = prstate.ndead = prstate.nunused = 0; memset(prstate.marked, 0, sizeof(prstate.marked)); + presult->ndeleted = 0; + presult->nnewlpdead = 0; + presult->off_loc = InvalidOffsetNumber; + maxoff = PageGetMaxOffsetNumber(page); tup.t_tableOid = RelationGetRelid(prstate.rel); @@ -290,8 +286,7 @@ heap_page_prune(Relation relation, Buffer buffer, * Set the offset number so that we can display it along with any * error that occurred while processing this tuple. */ - if (off_loc) - *off_loc = offnum; + presult->off_loc = offnum; prstate.htsv[offnum] = heap_prune_satisfies_vacuum(&prstate, &tup, buffer); @@ -309,8 +304,7 @@ heap_page_prune(Relation relation, Buffer buffer, continue; /* see preceding loop */ - if (off_loc) - *off_loc = offnum; + presult->off_loc = offnum; /* Nothing to do if slot is empty or already dead */ itemid = PageGetItemId(page, offnum); @@ -318,12 +312,11 @@ heap_page_prune(Relation relation, Buffer buffer, continue; /* Process this item or chain of items */ - ndeleted += heap_prune_chain(buffer, offnum, &prstate); + presult->ndeleted += heap_prune_chain(buffer, offnum, &prstate); } /* Clear the offset information once we have processed the given page. */ - if (off_loc) - *off_loc = InvalidOffsetNumber; + presult->off_loc = InvalidOffsetNumber; /* Any error while applying the changes is critical */ START_CRIT_SECTION(); @@ -419,9 +412,7 @@ heap_page_prune(Relation relation, Buffer buffer, END_CRIT_SECTION(); /* Record number of newly-set-LP_DEAD items for caller */ - *nnewlpdead = prstate.ndead; - - return ndeleted; + presult->nnewlpdead = prstate.ndead; } diff --git a/src/backend/access/heap/vacuumlazy.c b/src/backend/access/heap/vacuumlazy.c index 1a05adfa61..a3c756ab2e 100644 --- a/src/backend/access/heap/vacuumlazy.c +++ b/src/backend/access/heap/vacuumlazy.c @@ -1544,12 +1544,11 @@ lazy_scan_prune(LVRelState *vacrel, ItemId itemid; HeapTupleData tuple; HTSV_Result res; - int tuples_deleted, - tuples_frozen, + PruneResult presult; + int tuples_frozen, lpdead_items, live_tuples, recently_dead_tuples; - int nnewlpdead; HeapPageFreeze pagefrz; int64 fpi_before = pgWalUsage.wal_fpi; OffsetNumber deadoffsets[MaxHeapTuplesPerPage]; @@ -1572,7 +1571,6 @@ retry: pagefrz.FreezePageRelminMxid = vacrel->NewRelminMxid; pagefrz.NoFreezePageRelfrozenXid = vacrel->NewRelfrozenXid; pagefrz.NoFreezePageRelminMxid = vacrel->NewRelminMxid; - tuples_deleted = 0; tuples_frozen = 0; lpdead_items = 0; live_tuples = 0; @@ -1581,15 +1579,14 @@ retry: /* * Prune all HOT-update chains in this page. * - * We count tuples removed by the pruning step as tuples_deleted. Its - * final value can be thought of as the number of tuples that have been - * deleted from the table. It should not be confused with lpdead_items; + * We count the number of tuples removed from the page by the pruning step + * in presult.ndeleted. It should not be confused with lpdead_items; * lpdead_items's final value can be thought of as the number of tuples * that were deleted from indexes. */ - tuples_deleted = heap_page_prune(rel, buf, vacrel->vistest, - &nnewlpdead, - &vacrel->offnum); + heap_page_prune(rel, buf, vacrel->vistest, &presult); + + vacrel->offnum = presult.off_loc; /* * Now scan the page to collect LP_DEAD items and check for tuples @@ -1929,7 +1926,7 @@ retry: } /* Finally, add page-local counts to whole-VACUUM counts */ - vacrel->tuples_deleted += tuples_deleted; + vacrel->tuples_deleted += presult.ndeleted; vacrel->tuples_frozen += tuples_frozen; vacrel->lpdead_items += lpdead_items; vacrel->live_tuples += live_tuples; diff --git a/src/include/access/heapam.h b/src/include/access/heapam.h index 6598c4d7d8..a2ea3be52b 100644 --- a/src/include/access/heapam.h +++ b/src/include/access/heapam.h @@ -191,6 +191,21 @@ typedef struct HeapPageFreeze } HeapPageFreeze; +/* + * Per-page state returned from pruning + */ +typedef struct PruneResult +{ + int ndeleted; /* Number of tuples deleted from the page */ + int nnewlpdead; /* Number of newly LP_DEAD items */ + + /* + * Current tuple's offset in the line pointer array, used for error + * callback. + */ + OffsetNumber off_loc; +} PruneResult; + /* ---------------- * function prototypes for heap access method * @@ -284,10 +299,9 @@ extern TransactionId heap_index_delete_tuples(Relation rel, /* in heap/pruneheap.c */ struct GlobalVisState; extern void heap_page_prune_opt(Relation relation, Buffer buffer); -extern int heap_page_prune(Relation relation, Buffer buffer, +extern void heap_page_prune(Relation relation, Buffer buffer, struct GlobalVisState *vistest, - int *nnewlpdead, - OffsetNumber *off_loc); + PruneResult *presult); extern void heap_page_prune_execute(Buffer buffer, OffsetNumber *redirected, int nredirected, OffsetNumber *nowdead, int ndead, diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 0656c94416..8c30c0b1b6 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -2150,6 +2150,7 @@ ProjectionPath PromptInterruptContext ProtocolVersion PrsStorage +PruneResult PruneState PruneStepResult PsqlScanCallbacks -- 2.37.2