From ffe50d5901a8f9e76200abf2c6ef43e250cc25f7 Mon Sep 17 00:00:00 2001 From: Thomas Munro Date: Mon, 17 Aug 2020 20:59:32 +1200 Subject: [PATCH 2/2] Use specialized sort in compactify_tuples(). Micro-optimization: by using a sort function with inlined comparison and size we can improve page compaction performance. --- src/backend/storage/page/bufpage.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) diff --git a/src/backend/storage/page/bufpage.c b/src/backend/storage/page/bufpage.c index d708117a40..33d783e5f6 100644 --- a/src/backend/storage/page/bufpage.c +++ b/src/backend/storage/page/bufpage.c @@ -421,13 +421,17 @@ typedef struct itemIdSortData } itemIdSortData; typedef itemIdSortData *itemIdSort; -static int -itemoffcompare(const void *itemidp1, const void *itemidp2) -{ - /* Sort in decreasing itemoff order */ - return ((itemIdSort) itemidp2)->itemoff - - ((itemIdSort) itemidp1)->itemoff; -} +/* + * Instantiate a fast itemid_sort() function that sorts in decreasing offset + * order. + */ +#define SA_PREFIX itemid +#define SA_ELEMENT_TYPE itemIdSortData +#define SA_DEFINE +#define SA_SCOPE static +#define SA_ENABLE_SORT +#define SA_COMPARE(a, b) ((b)->itemoff - (a)->itemoff) +#include "lib/sort_utils.h" /* * After removing or marking some line pointers unused, move the tuples to @@ -441,8 +445,7 @@ compactify_tuples(itemIdSort itemidbase, int nitems, Page page) int i; /* sort itemIdSortData array into decreasing itemoff order */ - qsort((char *) itemidbase, nitems, sizeof(itemIdSortData), - itemoffcompare); + itemid_sort(itemidbase, nitems); upper = phdr->pd_special; for (i = 0; i < nitems; i++) -- 2.20.1