diff options
Diffstat (limited to 'src/backend/access/common')
| -rw-r--r-- | src/backend/access/common/tidstore.c | 81 |
1 files changed, 57 insertions, 24 deletions
diff --git a/src/backend/access/common/tidstore.c b/src/backend/access/common/tidstore.c index 3150a9d16df..cddbaf013bc 100644 --- a/src/backend/access/common/tidstore.c +++ b/src/backend/access/common/tidstore.c @@ -35,7 +35,7 @@ #define WORDS_PER_PAGE(n) ((n) / BITS_PER_BITMAPWORD + 1) /* number of offsets we can store in the header of a BlocktableEntry */ -#define NUM_FULL_OFFSETS ((sizeof(bitmapword) - sizeof(uint16)) / sizeof(OffsetNumber)) +#define NUM_FULL_OFFSETS ((sizeof(uintptr_t) - sizeof(uint8) - sizeof(int8)) / sizeof(OffsetNumber)) /* * This is named similarly to PagetableEntry in tidbitmap.c @@ -43,19 +43,50 @@ */ typedef struct BlocktableEntry { - uint16 nwords; - - /* - * We can store a small number of offsets here to avoid wasting space with - * a sparse bitmap. - */ - OffsetNumber full_offsets[NUM_FULL_OFFSETS]; + union + { + struct + { +#ifndef WORDS_BIGENDIAN + /* + * We need to position this member so that the backing radix tree + * can use the lowest bit for a pointer tag. In particular, it + * must be placed within 'header' so that it corresponds to the + * lowest byte in 'ptr'. We position 'nwords' along with it to + * avoid struct padding. + */ + uint8 flags; + + int8 nwords; +#endif + + /* + * We can store a small number of offsets here to avoid wasting + * space with a sparse bitmap. + */ + OffsetNumber full_offsets[NUM_FULL_OFFSETS]; + +#ifdef WORDS_BIGENDIAN + int8 nwords; + uint8 flags; +#endif + }; + uintptr_t ptr; + } header; bitmapword words[FLEXIBLE_ARRAY_MEMBER]; } BlocktableEntry; + +/* + * The type of 'nwords' limits the max number of words in the 'words' array. + * This computes the max offset we can actually store in the bitmap. In + * practice, it's almost always the same as MaxOffsetNumber. + */ +#define MAX_OFFSET_IN_BITMAP Min(BITS_PER_BITMAPWORD * PG_INT8_MAX - 1, MaxOffsetNumber) + #define MaxBlocktableEntrySize \ offsetof(BlocktableEntry, words) + \ - (sizeof(bitmapword) * WORDS_PER_PAGE(MaxOffsetNumber)) + (sizeof(bitmapword) * WORDS_PER_PAGE(MAX_OFFSET_IN_BITMAP)) #define RT_PREFIX local_ts #define RT_SCOPE static @@ -64,7 +95,8 @@ typedef struct BlocktableEntry #define RT_VALUE_TYPE BlocktableEntry #define RT_VARLEN_VALUE_SIZE(page) \ (offsetof(BlocktableEntry, words) + \ - sizeof(bitmapword) * (page)->nwords) + sizeof(bitmapword) * (page)->header.nwords) +#define RT_RUNTIME_EMBEDDABLE_VALUE #include "lib/radixtree.h" #define RT_PREFIX shared_ts @@ -75,7 +107,8 @@ typedef struct BlocktableEntry #define RT_VALUE_TYPE BlocktableEntry #define RT_VARLEN_VALUE_SIZE(page) \ (offsetof(BlocktableEntry, words) + \ - sizeof(bitmapword) * (page)->nwords) + sizeof(bitmapword) * (page)->header.nwords) +#define RT_RUNTIME_EMBEDDABLE_VALUE #include "lib/radixtree.h" /* Per-backend state for a TidStore */ @@ -350,13 +383,13 @@ TidStoreSetBlockOffsets(TidStore *ts, BlockNumber blkno, OffsetNumber *offsets, OffsetNumber off = offsets[i]; /* safety check to ensure we don't overrun bit array bounds */ - if (!OffsetNumberIsValid(off)) + if (off == InvalidOffsetNumber || off > MAX_OFFSET_IN_BITMAP) elog(ERROR, "tuple offset out of range: %u", off); - page->full_offsets[i] = off; + page->header.full_offsets[i] = off; } - page->nwords = 0; + page->header.nwords = 0; } else { @@ -371,7 +404,7 @@ TidStoreSetBlockOffsets(TidStore *ts, BlockNumber blkno, OffsetNumber *offsets, OffsetNumber off = offsets[idx]; /* safety check to ensure we don't overrun bit array bounds */ - if (!OffsetNumberIsValid(off)) + if (off == InvalidOffsetNumber || off > MAX_OFFSET_IN_BITMAP) elog(ERROR, "tuple offset out of range: %u", off); if (off >= next_word_threshold) @@ -385,8 +418,8 @@ TidStoreSetBlockOffsets(TidStore *ts, BlockNumber blkno, OffsetNumber *offsets, page->words[wordnum] = word; } - page->nwords = wordnum; - Assert(page->nwords == WORDS_PER_PAGE(offsets[num_offsets - 1])); + page->header.nwords = wordnum; + Assert(page->header.nwords == WORDS_PER_PAGE(offsets[num_offsets - 1])); } if (TidStoreIsShared(ts)) @@ -414,12 +447,12 @@ TidStoreIsMember(TidStore *ts, ItemPointer tid) if (page == NULL) return false; - if (page->nwords == 0) + if (page->header.nwords == 0) { /* we have offsets in the header */ for (int i = 0; i < NUM_FULL_OFFSETS; i++) { - if (page->full_offsets[i] == off) + if (page->header.full_offsets[i] == off) return true; } return false; @@ -430,7 +463,7 @@ TidStoreIsMember(TidStore *ts, ItemPointer tid) bitnum = BITNUM(off); /* no bitmap for the off */ - if (wordnum >= page->nwords) + if (wordnum >= page->header.nwords) return false; return (page->words[wordnum] & ((bitmapword) 1 << bitnum)) != 0; @@ -554,18 +587,18 @@ tidstore_iter_extract_tids(TidStoreIter *iter, BlockNumber blkno, result->num_offsets = 0; result->blkno = blkno; - if (page->nwords == 0) + if (page->header.nwords == 0) { /* we have offsets in the header */ for (int i = 0; i < NUM_FULL_OFFSETS; i++) { - if (page->full_offsets[i] != InvalidOffsetNumber) - result->offsets[result->num_offsets++] = page->full_offsets[i]; + if (page->header.full_offsets[i] != InvalidOffsetNumber) + result->offsets[result->num_offsets++] = page->header.full_offsets[i]; } } else { - for (wordnum = 0; wordnum < page->nwords; wordnum++) + for (wordnum = 0; wordnum < page->header.nwords; wordnum++) { bitmapword w = page->words[wordnum]; int off = wordnum * BITS_PER_BITMAPWORD; |