From 50bb6dfb24fb68559c87ce4e2785c9a65be9a674 Mon Sep 17 00:00:00 2001 From: Thomas Munro Date: Sat, 13 Mar 2021 17:30:56 +1300 Subject: [PATCH 6/9] Specialize the HeapTuple sort routine for ANALYZE. Instead of a branching comparator, use "encoded" format, based on 48 bit integers that can be compared by subtraction. --- src/backend/commands/analyze.c | 36 +++++++++------------------------- 1 file changed, 9 insertions(+), 27 deletions(-) diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c index 3a9f358dd4..e760821ef5 100644 --- a/src/backend/commands/analyze.c +++ b/src/backend/commands/analyze.c @@ -98,7 +98,6 @@ static VacAttrStats *examine_attribute(Relation onerel, int attnum, static int acquire_sample_rows(Relation onerel, int elevel, HeapTuple *rows, int targrows, double *totalrows, double *totaldeadrows); -static int compare_rows(const void *a, const void *b); static int acquire_inherited_sample_rows(Relation onerel, int elevel, HeapTuple *rows, int targrows, double *totalrows, double *totaldeadrows); @@ -998,6 +997,14 @@ examine_attribute(Relation onerel, int attnum, Node *index_expr) return stats; } +#define ST_SORT sort_heaptuples_by_tid +#define ST_ELEMENT_TYPE HeapTuple +#define ST_COMPARE(a, b) (itemptr_encode(&((*a)->t_self)) - itemptr_encode(&((*b)->t_self))) +#define ST_COMPARE_TYPE int64 +#define ST_SCOPE static +#define ST_DEFINE +#include "lib/sort_template.h" + /* * acquire_sample_rows -- acquire a random sample of rows from the table * @@ -1141,7 +1148,7 @@ acquire_sample_rows(Relation onerel, int elevel, * tuples are already sorted. */ if (numrows == targrows) - qsort((void *) rows, numrows, sizeof(HeapTuple), compare_rows); + sort_heaptuples_by_tid(rows, numrows); /* * Estimate total numbers of live and dead rows in relation, extrapolating @@ -1176,31 +1183,6 @@ acquire_sample_rows(Relation onerel, int elevel, return numrows; } -/* - * qsort comparator for sorting rows[] array - */ -static int -compare_rows(const void *a, const void *b) -{ - HeapTuple ha = *(const HeapTuple *) a; - HeapTuple hb = *(const HeapTuple *) b; - BlockNumber ba = ItemPointerGetBlockNumber(&ha->t_self); - OffsetNumber oa = ItemPointerGetOffsetNumber(&ha->t_self); - BlockNumber bb = ItemPointerGetBlockNumber(&hb->t_self); - OffsetNumber ob = ItemPointerGetOffsetNumber(&hb->t_self); - - if (ba < bb) - return -1; - if (ba > bb) - return 1; - if (oa < ob) - return -1; - if (oa > ob) - return 1; - return 0; -} - - /* * acquire_inherited_sample_rows -- acquire sample rows from inheritance tree * -- 2.30.1