diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/access/nbtree/nbtsearch.c | 19 |
1 files changed, 8 insertions, 11 deletions
diff --git a/src/backend/access/nbtree/nbtsearch.c b/src/backend/access/nbtree/nbtsearch.c index 2275553be78..c33438c4bbd 100644 --- a/src/backend/access/nbtree/nbtsearch.c +++ b/src/backend/access/nbtree/nbtsearch.c @@ -1580,7 +1580,7 @@ _bt_readpage(IndexScanDesc scan, ScanDirection dir, OffsetNumber offnum, so->currPos.currPage); } - /* initialize remaining currPos fields (before moreLeft/moreright) */ + /* initialize remaining currPos fields (before moreLeft/moreRight) */ so->currPos.lsn = BufferGetLSNAtomic(so->currPos.buf); so->currPos.dir = dir; so->currPos.nextTupleOffset = 0; @@ -2154,7 +2154,7 @@ _bt_readfirstpage(IndexScanDesc scan, OffsetNumber offnum, ScanDirection dir) so->numKilled = 0; /* just paranoia */ so->markItemIndex = -1; /* ditto */ - /* Initialize currPos for so->currPos */ + /* Initialize so->currPos for the first page (page in so->currPos.buf) */ if (so->needPrimScan) { Assert(so->numArrayKeys); @@ -2175,7 +2175,7 @@ _bt_readfirstpage(IndexScanDesc scan, OffsetNumber offnum, ScanDirection dir) } /* - * Attempt to load matching tuples from the page in so->currPos.buf. + * Attempt to load matching tuples from the first page. * * Note that _bt_readpage will finish initializing the so->currPos fields. * _bt_readpage also releases parallel scan (even when it returns false). @@ -2208,8 +2208,7 @@ _bt_readfirstpage(IndexScanDesc scan, OffsetNumber offnum, ScanDirection dir) * Caller's blkno is the next interesting page's link, taken from either the * previously-saved right link or left link. lastcurrblkno is the page that * was current at the point where the blkno link was saved, which we use to - * reason about concurrent page splits/page deletions during backwards scans - * (_bt_parallel_seize also requires it, regardless of scan direction). + * reason about concurrent page splits/page deletions during backwards scans. * * On entry, caller shouldn't hold any locks or pins on any page (we work * directly off of blkno and lastcurrblkno instead). Parallel scan callers @@ -2234,8 +2233,6 @@ _bt_readnextpage(IndexScanDesc scan, BlockNumber blkno, { Relation rel = scan->indexRelation; BTScanOpaque so = (BTScanOpaque) scan->opaque; - Page page; - BTPageOpaque opaque; Assert(so->currPos.currPage == lastcurrblkno || scan->parallel_scan != NULL); Assert(!BTScanPosIsPinned(so->currPos)); @@ -2251,14 +2248,14 @@ _bt_readnextpage(IndexScanDesc scan, BlockNumber blkno, for (;;) { - /* - * if we're at end of scan, give up and mark parallel scan as done, so - * that all the workers can finish their scan - */ + Page page; + BTPageOpaque opaque; + if (blkno == P_NONE || (ScanDirectionIsForward(dir) ? !so->currPos.moreRight : !so->currPos.moreLeft)) { + /* most recent _bt_readpage call (for lastcurrblkno) ended scan */ _bt_parallel_done(scan); BTScanPosInvalidate(so->currPos); return false; |