diff options
Diffstat (limited to 'src/backend/access/index/indexam.c')
| -rw-r--r-- | src/backend/access/index/indexam.c | 135 |
1 files changed, 130 insertions, 5 deletions
diff --git a/src/backend/access/index/indexam.c b/src/backend/access/index/indexam.c index 4822af95a32..ba27c1e86d9 100644 --- a/src/backend/access/index/indexam.c +++ b/src/backend/access/index/indexam.c @@ -20,6 +20,10 @@ * index_insert - insert an index tuple into a relation * index_markpos - mark a scan position * index_restrpos - restore a scan position + * index_parallelscan_estimate - estimate shared memory for parallel scan + * index_parallelscan_initialize - initialize parallel scan + * index_parallelrescan - (re)start a parallel scan of an index + * index_beginscan_parallel - join parallel index scan * index_getnext_tid - get the next TID from a scan * index_fetch_heap - get the scan's next heap tuple * index_getnext - get the next heap tuple from a scan @@ -120,7 +124,8 @@ do { \ } while(0) static IndexScanDesc index_beginscan_internal(Relation indexRelation, - int nkeys, int norderbys, Snapshot snapshot); + int nkeys, int norderbys, Snapshot snapshot, + ParallelIndexScanDesc pscan, bool temp_snap); /* ---------------------------------------------------------------- @@ -219,7 +224,7 @@ index_beginscan(Relation heapRelation, { IndexScanDesc scan; - scan = index_beginscan_internal(indexRelation, nkeys, norderbys, snapshot); + scan = index_beginscan_internal(indexRelation, nkeys, norderbys, snapshot, NULL, false); /* * Save additional parameters into the scandesc. Everything else was set @@ -244,7 +249,7 @@ index_beginscan_bitmap(Relation indexRelation, { IndexScanDesc scan; - scan = index_beginscan_internal(indexRelation, nkeys, 0, snapshot); + scan = index_beginscan_internal(indexRelation, nkeys, 0, snapshot, NULL, false); /* * Save additional parameters into the scandesc. Everything else was set @@ -260,8 +265,11 @@ index_beginscan_bitmap(Relation indexRelation, */ static IndexScanDesc index_beginscan_internal(Relation indexRelation, - int nkeys, int norderbys, Snapshot snapshot) + int nkeys, int norderbys, Snapshot snapshot, + ParallelIndexScanDesc pscan, bool temp_snap) { + IndexScanDesc scan; + RELATION_CHECKS; CHECK_REL_PROCEDURE(ambeginscan); @@ -276,8 +284,13 @@ index_beginscan_internal(Relation indexRelation, /* * Tell the AM to open a scan. */ - return indexRelation->rd_amroutine->ambeginscan(indexRelation, nkeys, + scan = indexRelation->rd_amroutine->ambeginscan(indexRelation, nkeys, norderbys); + /* Initialize information for parallel scan. */ + scan->parallel_scan = pscan; + scan->xs_temp_snap = temp_snap; + + return scan; } /* ---------------- @@ -341,6 +354,9 @@ index_endscan(IndexScanDesc scan) /* Release index refcount acquired by index_beginscan */ RelationDecrementReferenceCount(scan->indexRelation); + if (scan->xs_temp_snap) + UnregisterSnapshot(scan->xs_snapshot); + /* Release the scan data structure itself */ IndexScanEnd(scan); } @@ -389,6 +405,115 @@ index_restrpos(IndexScanDesc scan) scan->indexRelation->rd_amroutine->amrestrpos(scan); } +/* + * index_parallelscan_estimate - estimate shared memory for parallel scan + * + * Currently, we don't pass any information to the AM-specific estimator, + * so it can probably only return a constant. In the future, we might need + * to pass more information. + */ +Size +index_parallelscan_estimate(Relation indexRelation, Snapshot snapshot) +{ + Size nbytes; + + RELATION_CHECKS; + + nbytes = offsetof(ParallelIndexScanDescData, ps_snapshot_data); + nbytes = add_size(nbytes, EstimateSnapshotSpace(snapshot)); + nbytes = MAXALIGN(nbytes); + + /* + * If amestimateparallelscan is not provided, assume there is no + * AM-specific data needed. (It's hard to believe that could work, but + * it's easy enough to cater to it here.) + */ + if (indexRelation->rd_amroutine->amestimateparallelscan != NULL) + nbytes = add_size(nbytes, + indexRelation->rd_amroutine->amestimateparallelscan()); + + return nbytes; +} + +/* + * index_parallelscan_initialize - initialize parallel scan + * + * We initialize both the ParallelIndexScanDesc proper and the AM-specific + * information which follows it. + * + * This function calls access method specific initialization routine to + * initialize am specific information. Call this just once in the leader + * process; then, individual workers attach via index_beginscan_parallel. + */ +void +index_parallelscan_initialize(Relation heapRelation, Relation indexRelation, + Snapshot snapshot, ParallelIndexScanDesc target) +{ + Size offset; + + RELATION_CHECKS; + + offset = add_size(offsetof(ParallelIndexScanDescData, ps_snapshot_data), + EstimateSnapshotSpace(snapshot)); + offset = MAXALIGN(offset); + + target->ps_relid = RelationGetRelid(heapRelation); + target->ps_indexid = RelationGetRelid(indexRelation); + target->ps_offset = offset; + SerializeSnapshot(snapshot, target->ps_snapshot_data); + + /* aminitparallelscan is optional; assume no-op if not provided by AM */ + if (indexRelation->rd_amroutine->aminitparallelscan != NULL) + { + void *amtarget; + + amtarget = OffsetToPointer(target, offset); + indexRelation->rd_amroutine->aminitparallelscan(amtarget); + } +} + +/* ---------------- + * index_parallelrescan - (re)start a parallel scan of an index + * ---------------- + */ +void +index_parallelrescan(IndexScanDesc scan) +{ + SCAN_CHECKS; + + /* amparallelrescan is optional; assume no-op if not provided by AM */ + if (scan->indexRelation->rd_amroutine->amparallelrescan != NULL) + scan->indexRelation->rd_amroutine->amparallelrescan(scan); +} + +/* + * index_beginscan_parallel - join parallel index scan + * + * Caller must be holding suitable locks on the heap and the index. + */ +IndexScanDesc +index_beginscan_parallel(Relation heaprel, Relation indexrel, int nkeys, + int norderbys, ParallelIndexScanDesc pscan) +{ + Snapshot snapshot; + IndexScanDesc scan; + + Assert(RelationGetRelid(heaprel) == pscan->ps_relid); + snapshot = RestoreSnapshot(pscan->ps_snapshot_data); + RegisterSnapshot(snapshot); + scan = index_beginscan_internal(indexrel, nkeys, norderbys, snapshot, + pscan, true); + + /* + * Save additional parameters into the scandesc. Everything else was set + * up by index_beginscan_internal. + */ + scan->heapRelation = heaprel; + scan->xs_snapshot = snapshot; + + return scan; +} + /* ---------------- * index_getnext_tid - get the next TID from a scan * |