diff options
Diffstat (limited to 'src/include')
| -rw-r--r-- | src/include/access/tableam.h | 98 | ||||
| -rw-r--r-- | src/include/nodes/execnodes.h | 4 | ||||
| -rw-r--r-- | src/include/nodes/tidbitmap.h | 2 |
3 files changed, 96 insertions, 8 deletions
diff --git a/src/include/access/tableam.h b/src/include/access/tableam.h index 34813e40991..9bc1d24b4a6 100644 --- a/src/include/access/tableam.h +++ b/src/include/access/tableam.h @@ -31,6 +31,7 @@ struct BulkInsertStateData; struct IndexInfo; struct IndexBuildCallback; struct SampleScanState; +struct TBMIterateResult; struct VacuumParams; struct ValidateIndexState; @@ -527,8 +528,58 @@ typedef struct TableAmRoutine */ /* - * Acquire the next block in a sample scan. Return false if the sample - * scan is finished, true otherwise. + * Prepare to fetch / check / return tuples from `tbmres->blockno` as part + * of a bitmap table scan. `scan` was started via table_beginscan_bm(). + * Return false if there's no tuples to be found on the page, true + * otherwise. + * + * This will typically read and pin the target block, and do the necessary + * work to allow scan_bitmap_next_tuple() to return tuples (e.g. it might + * make sense to perform tuple visibility checks at this time). For some + * AMs it will make more sense to do all the work referencing `tbmres` + * contents here, for others it might be better to defer more work to + * scan_bitmap_next_tuple. + * + * If `tbmres->blockno` is -1, this is a lossy scan and all visible tuples + * on the page have to be returned, otherwise the tuples at offsets in + * `tbmres->offsets` need to be returned. + * + * XXX: Currently this may only be implemented if the AM uses md.c as its + * storage manager, and uses ItemPointer->ip_blkid in a manner that maps + * blockids directly to the underlying storage. nodeBitmapHeapscan.c + * performs prefetching directly using that interface. This probably + * needs to be rectified at a later point. + * + * XXX: Currently this may only be implemented if the AM uses the + * visibilitymap, as nodeBitmapHeapscan.c unconditionally accesses it to + * perform prefetching. This probably needs to be rectified at a later + * point. + * + * Optional callback, but either both scan_bitmap_next_block and + * scan_bitmap_next_tuple need to exist, or neither. + */ + bool (*scan_bitmap_next_block) (TableScanDesc scan, + struct TBMIterateResult *tbmres); + + /* + * Fetch the next tuple of a bitmap table scan into `slot` and return true + * if a visible tuple was found, false otherwise. + * + * For some AMs it will make more sense to do all the work referencing + * `tbmres` contents in scan_bitmap_next_block, for others it might be + * better to defer more work to this callback. + * + * Optional callback, but either both scan_bitmap_next_block and + * scan_bitmap_next_tuple need to exist, or neither. + */ + bool (*scan_bitmap_next_tuple) (TableScanDesc scan, + struct TBMIterateResult *tbmres, + TupleTableSlot *slot); + + /* + * Prepare to fetch tuples from the next block in a sample scan. Return + * false if the sample scan is finished, true otherwise. `scan` was + * started via table_beginscan_sampling(). * * Typically this will first determine the target block by call the * TsmRoutine's NextSampleBlock() callback if not NULL, or alternatively @@ -1396,8 +1447,44 @@ table_relation_estimate_size(Relation rel, int32 *attr_widths, */ /* - * Acquire the next block in a sample scan. Returns false if the sample scan - * is finished, true otherwise. + * Prepare to fetch / check / return tuples from `tbmres->blockno` as part of + * a bitmap table scan. `scan` needs to have been started via + * table_beginscan_bm(). Returns false if there's no tuples to be found on the + * page, true otherwise. + * + * Note, this is an optionally implemented function, therefore should only be + * used after verifying the presence (at plan time or such). + */ +static inline bool +table_scan_bitmap_next_block(TableScanDesc scan, + struct TBMIterateResult *tbmres) +{ + return scan->rs_rd->rd_tableam->scan_bitmap_next_block(scan, + tbmres); +} + +/* + * Fetch the next tuple of a bitmap table scan into `slot` and return true if + * a visible tuple was found, false otherwise. + * table_scan_bitmap_next_block() needs to previously have selected a + * block (i.e. returned true), and no previous + * table_scan_bitmap_next_tuple() for the same block may have + * returned false. + */ +static inline bool +table_scan_bitmap_next_tuple(TableScanDesc scan, + struct TBMIterateResult *tbmres, + TupleTableSlot *slot) +{ + return scan->rs_rd->rd_tableam->scan_bitmap_next_tuple(scan, + tbmres, + slot); +} + +/* + * Prepare to fetch tuples from the next block in a sample scan. Returns false + * if the sample scan is finished, true otherwise. `scan` needs to have been + * started via table_beginscan_sampling(). * * This will call the TsmRoutine's NextSampleBlock() callback if necessary * (i.e. NextSampleBlock is not NULL), or perform a sequential scan over the @@ -1413,7 +1500,8 @@ table_scan_sample_next_block(TableScanDesc scan, /* * Fetch the next sample tuple into `slot` and return true if a visible tuple * was found, false otherwise. table_scan_sample_next_block() needs to - * previously have selected a block (i.e. returned true). + * previously have selected a block (i.e. returned true), and no previous + * table_scan_sample_next_tuple() for the same block may have returned false. * * This will call the TsmRoutine's NextSampleTuple() callback. */ diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h index 437a191b458..5b4ea6c2355 100644 --- a/src/include/nodes/execnodes.h +++ b/src/include/nodes/execnodes.h @@ -1507,7 +1507,7 @@ typedef struct ParallelBitmapHeapState * tbmiterator iterator for scanning current pages * tbmres current-page data * can_skip_fetch can we potentially skip tuple fetches in this scan? - * skip_fetch are we skipping tuple fetches on this page? + * return_empty_tuples number of empty tuples to return * vmbuffer buffer for visibility-map lookups * pvmbuffer ditto, for prefetched pages * exact_pages total number of exact pages retrieved @@ -1531,7 +1531,7 @@ typedef struct BitmapHeapScanState TBMIterator *tbmiterator; TBMIterateResult *tbmres; bool can_skip_fetch; - bool skip_fetch; + int return_empty_tuples; Buffer vmbuffer; Buffer pvmbuffer; long exact_pages; diff --git a/src/include/nodes/tidbitmap.h b/src/include/nodes/tidbitmap.h index 2645085b344..6a7f3054a41 100644 --- a/src/include/nodes/tidbitmap.h +++ b/src/include/nodes/tidbitmap.h @@ -37,7 +37,7 @@ typedef struct TBMIterator TBMIterator; typedef struct TBMSharedIterator TBMSharedIterator; /* Result structure for tbm_iterate */ -typedef struct +typedef struct TBMIterateResult { BlockNumber blockno; /* page number containing tuples */ int ntuples; /* -1 indicates lossy result */ |