diff options
Diffstat (limited to 'src/backend/access/spgist/spgdoinsert.c')
| -rw-r--r-- | src/backend/access/spgist/spgdoinsert.c | 34 |
1 files changed, 30 insertions, 4 deletions
diff --git a/src/backend/access/spgist/spgdoinsert.c b/src/backend/access/spgist/spgdoinsert.c index 5f6bcdd6b72..1fd331cbdfd 100644 --- a/src/backend/access/spgist/spgdoinsert.c +++ b/src/backend/access/spgist/spgdoinsert.c @@ -1836,9 +1836,13 @@ spgSplitNodeAction(Relation index, SpGistState *state, } /* - * Insert one item into the index + * Insert one item into the index. + * + * Returns true on success, false if we failed to complete the insertion + * because of conflict with a concurrent insert. In the latter case, + * caller should re-call spgdoinsert() with the same args. */ -void +bool spgdoinsert(Relation index, SpGistState *state, ItemPointer heapPtr, Datum datum, bool isnull) { @@ -1927,12 +1931,32 @@ spgdoinsert(Relation index, SpGistState *state, &isNew); current.blkno = BufferGetBlockNumber(current.buffer); } - else if (parent.buffer == InvalidBuffer || - current.blkno != parent.blkno) + else if (parent.buffer == InvalidBuffer) { + /* we hold no parent-page lock, so no deadlock is possible */ current.buffer = ReadBuffer(index, current.blkno); LockBuffer(current.buffer, BUFFER_LOCK_EXCLUSIVE); } + else if (current.blkno != parent.blkno) + { + /* descend to a new child page */ + current.buffer = ReadBuffer(index, current.blkno); + + /* + * Attempt to acquire lock on child page. We must beware of + * deadlock against another insertion process descending from that + * page to our parent page (see README). If we fail to get lock, + * abandon the insertion and tell our caller to start over. XXX + * this could be improved; perhaps it'd be worth sleeping a bit + * before giving up? + */ + if (!ConditionalLockBuffer(current.buffer)) + { + ReleaseBuffer(current.buffer); + UnlockReleaseBuffer(parent.buffer); + return false; + } + } else { /* inner tuple can be stored on the same page as parent one */ @@ -2131,4 +2155,6 @@ spgdoinsert(Relation index, SpGistState *state, SpGistSetLastUsedPage(index, parent.buffer); UnlockReleaseBuffer(parent.buffer); } + + return true; } |