diff options
Diffstat (limited to 'src/backend/access/heap/heapam.c')
| -rw-r--r-- | src/backend/access/heap/heapam.c | 41 |
1 files changed, 29 insertions, 12 deletions
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c index 1a8d2f2d0b5..f0c2394e600 100644 --- a/src/backend/access/heap/heapam.c +++ b/src/backend/access/heap/heapam.c @@ -80,8 +80,9 @@ bool synchronize_seqscans = true; static HeapScanDesc heap_beginscan_internal(Relation relation, Snapshot snapshot, int nkeys, ScanKey key, - bool allow_strat, bool allow_sync, - bool is_bitmapscan, bool temp_snap); + bool allow_strat, bool allow_sync, bool allow_pagemode, + bool is_bitmapscan, bool is_samplescan, + bool temp_snap); static HeapTuple heap_prepare_insert(Relation relation, HeapTuple tup, TransactionId xid, CommandId cid, int options); static XLogRecPtr log_heap_update(Relation reln, Buffer oldbuf, @@ -294,9 +295,10 @@ initscan(HeapScanDesc scan, ScanKey key, bool is_rescan) /* * Currently, we don't have a stats counter for bitmap heap scans (but the - * underlying bitmap index scans will be counted). + * underlying bitmap index scans will be counted) or sample scans (we only + * update stats for tuple fetches there) */ - if (!scan->rs_bitmapscan) + if (!scan->rs_bitmapscan && !scan->rs_samplescan) pgstat_count_heap_scan(scan->rs_rd); } @@ -315,7 +317,7 @@ heap_setscanlimits(HeapScanDesc scan, BlockNumber startBlk, BlockNumber numBlks) * In page-at-a-time mode it performs additional work, namely determining * which tuples on the page are visible. */ -static void +void heapgetpage(HeapScanDesc scan, BlockNumber page) { Buffer buffer; @@ -1310,6 +1312,9 @@ heap_openrv_extended(const RangeVar *relation, LOCKMODE lockmode, * HeapScanDesc for a bitmap heap scan. Although that scan technology is * really quite unlike a standard seqscan, there is just enough commonality * to make it worth using the same data structure. + * + * heap_beginscan_samplingscan is alternate entry point for setting up a + * HeapScanDesc for a TABLESAMPLE scan. * ---------------- */ HeapScanDesc @@ -1317,7 +1322,7 @@ heap_beginscan(Relation relation, Snapshot snapshot, int nkeys, ScanKey key) { return heap_beginscan_internal(relation, snapshot, nkeys, key, - true, true, false, false); + true, true, true, false, false, false); } HeapScanDesc @@ -1327,7 +1332,7 @@ heap_beginscan_catalog(Relation relation, int nkeys, ScanKey key) Snapshot snapshot = RegisterSnapshot(GetCatalogSnapshot(relid)); return heap_beginscan_internal(relation, snapshot, nkeys, key, - true, true, false, true); + true, true, true, false, false, true); } HeapScanDesc @@ -1336,7 +1341,8 @@ heap_beginscan_strat(Relation relation, Snapshot snapshot, bool allow_strat, bool allow_sync) { return heap_beginscan_internal(relation, snapshot, nkeys, key, - allow_strat, allow_sync, false, false); + allow_strat, allow_sync, true, + false, false, false); } HeapScanDesc @@ -1344,14 +1350,24 @@ heap_beginscan_bm(Relation relation, Snapshot snapshot, int nkeys, ScanKey key) { return heap_beginscan_internal(relation, snapshot, nkeys, key, - false, false, true, false); + false, false, true, true, false, false); +} + +HeapScanDesc +heap_beginscan_sampling(Relation relation, Snapshot snapshot, + int nkeys, ScanKey key, + bool allow_strat, bool allow_pagemode) +{ + return heap_beginscan_internal(relation, snapshot, nkeys, key, + allow_strat, false, allow_pagemode, + false, true, false); } static HeapScanDesc heap_beginscan_internal(Relation relation, Snapshot snapshot, int nkeys, ScanKey key, - bool allow_strat, bool allow_sync, - bool is_bitmapscan, bool temp_snap) + bool allow_strat, bool allow_sync, bool allow_pagemode, + bool is_bitmapscan, bool is_samplescan, bool temp_snap) { HeapScanDesc scan; @@ -1373,6 +1389,7 @@ heap_beginscan_internal(Relation relation, Snapshot snapshot, scan->rs_snapshot = snapshot; scan->rs_nkeys = nkeys; scan->rs_bitmapscan = is_bitmapscan; + scan->rs_samplescan = is_samplescan; scan->rs_strategy = NULL; /* set in initscan */ scan->rs_allow_strat = allow_strat; scan->rs_allow_sync = allow_sync; @@ -1381,7 +1398,7 @@ heap_beginscan_internal(Relation relation, Snapshot snapshot, /* * we can use page-at-a-time mode if it's an MVCC-safe snapshot */ - scan->rs_pageatatime = IsMVCCSnapshot(snapshot); + scan->rs_pageatatime = allow_pagemode && IsMVCCSnapshot(snapshot); /* * For a seqscan in a serializable transaction, acquire a predicate lock |