diff options
| -rw-r--r-- | src/backend/access/nbtree/nbtree.c | 4 | ||||
| -rw-r--r-- | src/backend/access/nbtree/nbtsearch.c | 40 |
2 files changed, 17 insertions, 27 deletions
diff --git a/src/backend/access/nbtree/nbtree.c b/src/backend/access/nbtree/nbtree.c index 484ede8c2e1..2919b12639d 100644 --- a/src/backend/access/nbtree/nbtree.c +++ b/src/backend/access/nbtree/nbtree.c @@ -762,13 +762,15 @@ _bt_parallel_done(IndexScanDesc scan) BTParallelScanDesc btscan; bool status_changed = false; + Assert(!BTScanPosIsValid(so->currPos)); + /* Do nothing, for non-parallel scans */ if (parallel_scan == NULL) return; /* * Should not mark parallel scan done when there's still a pending - * primitive index scan + * primitive index scan (defensive) */ if (so->needPrimScan) return; diff --git a/src/backend/access/nbtree/nbtsearch.c b/src/backend/access/nbtree/nbtsearch.c index e718668ed69..177bc226aaf 100644 --- a/src/backend/access/nbtree/nbtsearch.c +++ b/src/backend/access/nbtree/nbtsearch.c @@ -1161,28 +1161,18 @@ _bt_first(IndexScanDesc scan, ScanDirection dir) * If we found no usable boundary keys, we have to start from one end of * the tree. Walk down that edge to the first or last key, and scan from * there. + * + * Note: calls _bt_readfirstpage for us, which releases the parallel scan. */ if (keysz == 0) - { - bool match; - - match = _bt_endpoint(scan, dir); - - if (!match) - { - /* No match, so mark (parallel) scan finished */ - _bt_parallel_done(scan); - } - - return match; - } + return _bt_endpoint(scan, dir); /* * We want to start the scan somewhere within the index. Set up an * insertion scankey we can use to search for the boundary point we * identified above. The insertion scankey is built using the keys * identified by startKeys[]. (Remaining insertion scankey fields are - * initialized after initial-positioning strategy is finalized.) + * initialized after initial-positioning scan keys are finalized.) */ Assert(keysz <= INDEX_MAX_KEYS); for (i = 0; i < keysz; i++) @@ -1425,12 +1415,7 @@ _bt_first(IndexScanDesc scan, ScanDirection dir) if (!BufferIsValid(so->currPos.buf)) { - /* - * Mark parallel scan as done, so that all the workers can finish - * their scan. - */ _bt_parallel_done(scan); - BTScanPosInvalidate(so->currPos); return false; } } @@ -2267,8 +2252,8 @@ _bt_readnextpage(IndexScanDesc scan, BlockNumber blkno, !so->currPos.moreRight : !so->currPos.moreLeft)) { /* most recent _bt_readpage call (for lastcurrblkno) ended scan */ - _bt_parallel_done(scan); BTScanPosInvalidate(so->currPos); + _bt_parallel_done(scan); return false; } @@ -2288,8 +2273,8 @@ _bt_readnextpage(IndexScanDesc scan, BlockNumber blkno, if (so->currPos.buf == InvalidBuffer) { /* must have been a concurrent deletion of leftmost page */ - _bt_parallel_done(scan); BTScanPosInvalidate(so->currPos); + _bt_parallel_done(scan); return false; } } @@ -2564,8 +2549,10 @@ _bt_get_endpoint(Relation rel, uint32 level, bool rightmost) * * This is used by _bt_first() to set up a scan when we've determined * that the scan must start at the beginning or end of the index (for - * a forward or backward scan respectively). Exit conditions are the - * same as for _bt_first(). + * a forward or backward scan respectively). + * + * Parallel scan callers must have seized the scan before calling here. + * Exit conditions are the same as for _bt_first(). */ static bool _bt_endpoint(IndexScanDesc scan, ScanDirection dir) @@ -2577,10 +2564,11 @@ _bt_endpoint(IndexScanDesc scan, ScanDirection dir) OffsetNumber start; BTScanPosItem *currItem; + Assert(!BTScanPosIsValid(so->currPos)); + /* * Scan down to the leftmost or rightmost leaf page. This is a simplified - * version of _bt_search(). We don't maintain a stack since we know we - * won't need it. + * version of _bt_search(). */ so->currPos.buf = _bt_get_endpoint(rel, 0, ScanDirectionIsBackward(dir)); @@ -2591,7 +2579,7 @@ _bt_endpoint(IndexScanDesc scan, ScanDirection dir) * exists. */ PredicateLockRelation(rel, scan->xs_snapshot); - BTScanPosInvalidate(so->currPos); + _bt_parallel_done(scan); return false; } |