diff options
Diffstat (limited to 'src/backend/access')
| -rw-r--r-- | src/backend/access/heap/visibilitymap.c | 74 |
1 files changed, 27 insertions, 47 deletions
diff --git a/src/backend/access/heap/visibilitymap.c b/src/backend/access/heap/visibilitymap.c index 931ae81fd6d..64dfe06b261 100644 --- a/src/backend/access/heap/visibilitymap.c +++ b/src/backend/access/heap/visibilitymap.c @@ -89,6 +89,7 @@ #include "access/visibilitymap.h" #include "access/xlog.h" #include "miscadmin.h" +#include "port/pg_bitutils.h" #include "storage/bufmgr.h" #include "storage/lmgr.h" #include "storage/smgr.h" @@ -115,43 +116,11 @@ #define HEAPBLK_TO_MAPBYTE(x) (((x) % HEAPBLOCKS_PER_PAGE) / HEAPBLOCKS_PER_BYTE) #define HEAPBLK_TO_OFFSET(x) (((x) % HEAPBLOCKS_PER_BYTE) * BITS_PER_HEAPBLOCK) -/* tables for fast counting of set bits for visible and frozen */ -static const uint8 number_of_ones_for_visible[256] = { - 0, 1, 0, 1, 1, 2, 1, 2, 0, 1, 0, 1, 1, 2, 1, 2, - 1, 2, 1, 2, 2, 3, 2, 3, 1, 2, 1, 2, 2, 3, 2, 3, - 0, 1, 0, 1, 1, 2, 1, 2, 0, 1, 0, 1, 1, 2, 1, 2, - 1, 2, 1, 2, 2, 3, 2, 3, 1, 2, 1, 2, 2, 3, 2, 3, - 1, 2, 1, 2, 2, 3, 2, 3, 1, 2, 1, 2, 2, 3, 2, 3, - 2, 3, 2, 3, 3, 4, 3, 4, 2, 3, 2, 3, 3, 4, 3, 4, - 1, 2, 1, 2, 2, 3, 2, 3, 1, 2, 1, 2, 2, 3, 2, 3, - 2, 3, 2, 3, 3, 4, 3, 4, 2, 3, 2, 3, 3, 4, 3, 4, - 0, 1, 0, 1, 1, 2, 1, 2, 0, 1, 0, 1, 1, 2, 1, 2, - 1, 2, 1, 2, 2, 3, 2, 3, 1, 2, 1, 2, 2, 3, 2, 3, - 0, 1, 0, 1, 1, 2, 1, 2, 0, 1, 0, 1, 1, 2, 1, 2, - 1, 2, 1, 2, 2, 3, 2, 3, 1, 2, 1, 2, 2, 3, 2, 3, - 1, 2, 1, 2, 2, 3, 2, 3, 1, 2, 1, 2, 2, 3, 2, 3, - 2, 3, 2, 3, 3, 4, 3, 4, 2, 3, 2, 3, 3, 4, 3, 4, - 1, 2, 1, 2, 2, 3, 2, 3, 1, 2, 1, 2, 2, 3, 2, 3, - 2, 3, 2, 3, 3, 4, 3, 4, 2, 3, 2, 3, 3, 4, 3, 4 -}; -static const uint8 number_of_ones_for_frozen[256] = { - 0, 0, 1, 1, 0, 0, 1, 1, 1, 1, 2, 2, 1, 1, 2, 2, - 0, 0, 1, 1, 0, 0, 1, 1, 1, 1, 2, 2, 1, 1, 2, 2, - 1, 1, 2, 2, 1, 1, 2, 2, 2, 2, 3, 3, 2, 2, 3, 3, - 1, 1, 2, 2, 1, 1, 2, 2, 2, 2, 3, 3, 2, 2, 3, 3, - 0, 0, 1, 1, 0, 0, 1, 1, 1, 1, 2, 2, 1, 1, 2, 2, - 0, 0, 1, 1, 0, 0, 1, 1, 1, 1, 2, 2, 1, 1, 2, 2, - 1, 1, 2, 2, 1, 1, 2, 2, 2, 2, 3, 3, 2, 2, 3, 3, - 1, 1, 2, 2, 1, 1, 2, 2, 2, 2, 3, 3, 2, 2, 3, 3, - 1, 1, 2, 2, 1, 1, 2, 2, 2, 2, 3, 3, 2, 2, 3, 3, - 1, 1, 2, 2, 1, 1, 2, 2, 2, 2, 3, 3, 2, 2, 3, 3, - 2, 2, 3, 3, 2, 2, 3, 3, 3, 3, 4, 4, 3, 3, 4, 4, - 2, 2, 3, 3, 2, 2, 3, 3, 3, 3, 4, 4, 3, 3, 4, 4, - 1, 1, 2, 2, 1, 1, 2, 2, 2, 2, 3, 3, 2, 2, 3, 3, - 1, 1, 2, 2, 1, 1, 2, 2, 2, 2, 3, 3, 2, 2, 3, 3, - 2, 2, 3, 3, 2, 2, 3, 3, 3, 3, 4, 4, 3, 3, 4, 4, - 2, 2, 3, 3, 2, 2, 3, 3, 3, 3, 4, 4, 3, 3, 4, 4 -}; +/* Masks for counting subsets of bits in the visibility map. */ +#define VISIBLE_MASK64 UINT64CONST(0x5555555555555555) /* The lower bit of each + * bit pair */ +#define FROZEN_MASK64 UINT64CONST(0xaaaaaaaaaaaaaaaa) /* The upper bit of each + * bit pair */ /* prototypes for internal routines */ static Buffer vm_readbuf(Relation rel, BlockNumber blkno, bool extend); @@ -408,18 +377,16 @@ void visibilitymap_count(Relation rel, BlockNumber *all_visible, BlockNumber *all_frozen) { BlockNumber mapBlock; + BlockNumber nvisible = 0; + BlockNumber nfrozen = 0; /* all_visible must be specified */ Assert(all_visible); - *all_visible = 0; - if (all_frozen) - *all_frozen = 0; - for (mapBlock = 0;; mapBlock++) { Buffer mapBuffer; - unsigned char *map; + uint64 *map; int i; /* @@ -436,17 +403,30 @@ visibilitymap_count(Relation rel, BlockNumber *all_visible, BlockNumber *all_fro * immediately stale anyway if anyone is concurrently setting or * clearing bits, and we only really need an approximate value. */ - map = (unsigned char *) PageGetContents(BufferGetPage(mapBuffer)); + map = (uint64 *) PageGetContents(BufferGetPage(mapBuffer)); - for (i = 0; i < MAPSIZE; i++) + StaticAssertStmt(MAPSIZE % sizeof(uint64) == 0, + "unsupported MAPSIZE"); + if (all_frozen == NULL) { - *all_visible += number_of_ones_for_visible[map[i]]; - if (all_frozen) - *all_frozen += number_of_ones_for_frozen[map[i]]; + for (i = 0; i < MAPSIZE / sizeof(uint64); i++) + nvisible += pg_popcount64(map[i] & VISIBLE_MASK64); + } + else + { + for (i = 0; i < MAPSIZE / sizeof(uint64); i++) + { + nvisible += pg_popcount64(map[i] & VISIBLE_MASK64); + nfrozen += pg_popcount64(map[i] & FROZEN_MASK64); + } } ReleaseBuffer(mapBuffer); } + + *all_visible = nvisible; + if (all_frozen) + *all_frozen = nfrozen; } /* |