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Diffstat (limited to 'src/include/nodes/tidbitmap.h')
-rw-r--r-- | src/include/nodes/tidbitmap.h | 75 |
1 files changed, 75 insertions, 0 deletions
diff --git a/src/include/nodes/tidbitmap.h b/src/include/nodes/tidbitmap.h new file mode 100644 index 0000000..b64e364 --- /dev/null +++ b/src/include/nodes/tidbitmap.h @@ -0,0 +1,75 @@ +/*------------------------------------------------------------------------- + * + * tidbitmap.h + * PostgreSQL tuple-id (TID) bitmap package + * + * This module provides bitmap data structures that are spiritually + * similar to Bitmapsets, but are specially adapted to store sets of + * tuple identifiers (TIDs), or ItemPointers. In particular, the division + * of an ItemPointer into BlockNumber and OffsetNumber is catered for. + * Also, since we wish to be able to store very large tuple sets in + * memory with this data structure, we support "lossy" storage, in which + * we no longer remember individual tuple offsets on a page but only the + * fact that a particular page needs to be visited. + * + * + * Copyright (c) 2003-2023, PostgreSQL Global Development Group + * + * src/include/nodes/tidbitmap.h + * + *------------------------------------------------------------------------- + */ +#ifndef TIDBITMAP_H +#define TIDBITMAP_H + +#include "storage/itemptr.h" +#include "utils/dsa.h" + + +/* + * Actual bitmap representation is private to tidbitmap.c. Callers can + * do IsA(x, TIDBitmap) on it, but nothing else. + */ +typedef struct TIDBitmap TIDBitmap; + +/* Likewise, TBMIterator is private */ +typedef struct TBMIterator TBMIterator; +typedef struct TBMSharedIterator TBMSharedIterator; + +/* Result structure for tbm_iterate */ +typedef struct TBMIterateResult +{ + BlockNumber blockno; /* page number containing tuples */ + int ntuples; /* -1 indicates lossy result */ + bool recheck; /* should the tuples be rechecked? */ + /* Note: recheck is always true if ntuples < 0 */ + OffsetNumber offsets[FLEXIBLE_ARRAY_MEMBER]; +} TBMIterateResult; + +/* function prototypes in nodes/tidbitmap.c */ + +extern TIDBitmap *tbm_create(long maxbytes, dsa_area *dsa); +extern void tbm_free(TIDBitmap *tbm); +extern void tbm_free_shared_area(dsa_area *dsa, dsa_pointer dp); + +extern void tbm_add_tuples(TIDBitmap *tbm, + const ItemPointer tids, int ntids, + bool recheck); +extern void tbm_add_page(TIDBitmap *tbm, BlockNumber pageno); + +extern void tbm_union(TIDBitmap *a, const TIDBitmap *b); +extern void tbm_intersect(TIDBitmap *a, const TIDBitmap *b); + +extern bool tbm_is_empty(const TIDBitmap *tbm); + +extern TBMIterator *tbm_begin_iterate(TIDBitmap *tbm); +extern dsa_pointer tbm_prepare_shared_iterate(TIDBitmap *tbm); +extern TBMIterateResult *tbm_iterate(TBMIterator *iterator); +extern TBMIterateResult *tbm_shared_iterate(TBMSharedIterator *iterator); +extern void tbm_end_iterate(TBMIterator *iterator); +extern void tbm_end_shared_iterate(TBMSharedIterator *iterator); +extern TBMSharedIterator *tbm_attach_shared_iterate(dsa_area *dsa, + dsa_pointer dp); +extern long tbm_calculate_entries(double maxbytes); + +#endif /* TIDBITMAP_H */ |