diff options
Diffstat (limited to 'src/backend/access/heap/visibilitymap.c')
| -rw-r--r-- | src/backend/access/heap/visibilitymap.c | 73 |
1 files changed, 48 insertions, 25 deletions
diff --git a/src/backend/access/heap/visibilitymap.c b/src/backend/access/heap/visibilitymap.c index 9657cd0a632..931ae81fd6d 100644 --- a/src/backend/access/heap/visibilitymap.c +++ b/src/backend/access/heap/visibilitymap.c @@ -89,12 +89,12 @@ #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" #include "utils/inval.h" + /*#define TRACE_VISIBILITYMAP */ /* @@ -115,9 +115,43 @@ #define HEAPBLK_TO_MAPBYTE(x) (((x) % HEAPBLOCKS_PER_PAGE) / HEAPBLOCKS_PER_BYTE) #define HEAPBLK_TO_OFFSET(x) (((x) % HEAPBLOCKS_PER_BYTE) * BITS_PER_HEAPBLOCK) -/* Masks for bit counting bits in the visibility map. */ -#define VISIBLE_MASK64 0x5555555555555555 /* The lower bit of each bit pair */ -#define FROZEN_MASK64 0xaaaaaaaaaaaaaaaa /* The upper bit of each bit pair */ +/* 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 +}; /* prototypes for internal routines */ static Buffer vm_readbuf(Relation rel, BlockNumber blkno, bool extend); @@ -374,16 +408,18 @@ 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; - uint64 *map; + unsigned char *map; int i; /* @@ -400,30 +436,17 @@ 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 = (uint64 *) PageGetContents(BufferGetPage(mapBuffer)); + map = (unsigned char *) PageGetContents(BufferGetPage(mapBuffer)); - StaticAssertStmt(MAPSIZE % sizeof(uint64) == 0, - "unsupported MAPSIZE"); - if (all_frozen == NULL) - { - for (i = 0; i < MAPSIZE / sizeof(uint64); i++) - nvisible += pg_popcount64(map[i] & VISIBLE_MASK64); - } - else + for (i = 0; i < MAPSIZE; i++) { - for (i = 0; i < MAPSIZE / sizeof(uint64); i++) - { - nvisible += pg_popcount64(map[i] & VISIBLE_MASK64); - nfrozen += pg_popcount64(map[i] & FROZEN_MASK64); - } + *all_visible += number_of_ones_for_visible[map[i]]; + if (all_frozen) + *all_frozen += number_of_ones_for_frozen[map[i]]; } ReleaseBuffer(mapBuffer); } - - *all_visible = nvisible; - if (all_frozen) - *all_frozen = nfrozen; } /* |