diff options
Diffstat (limited to 'src/backend/access/gist/gist.c')
| -rw-r--r-- | src/backend/access/gist/gist.c | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/src/backend/access/gist/gist.c b/src/backend/access/gist/gist.c index 769aca42e3b..d70a138f54d 100644 --- a/src/backend/access/gist/gist.c +++ b/src/backend/access/gist/gist.c @@ -639,6 +639,7 @@ gistdoinsert(Relation r, IndexTuple itup, Size freespace, /* Start from the root */ firststack.blkno = GIST_ROOT_BLKNO; firststack.lsn = 0; + firststack.retry_from_parent = false; firststack.parent = NULL; firststack.downlinkoffnum = InvalidOffsetNumber; state.stack = stack = &firststack; @@ -651,6 +652,21 @@ gistdoinsert(Relation r, IndexTuple itup, Size freespace, */ for (;;) { + /* + * If we split an internal page while descending the tree, we have to + * retry at the parent. (Normally, the LSN-NSN interlock below would + * also catch this and cause us to retry. But LSNs are not updated + * during index build.) + */ + while (stack->retry_from_parent) + { + if (xlocked) + LockBuffer(stack->buffer, GIST_UNLOCK); + xlocked = false; + ReleaseBuffer(stack->buffer); + state.stack = stack = stack->parent; + } + if (XLogRecPtrIsInvalid(stack->lsn)) stack->buffer = ReadBuffer(state.r, stack->blkno); @@ -1376,6 +1392,23 @@ gistfinishsplit(GISTInsertState *state, GISTInsertStack *stack, unlockbuf /* Unlock stack->buffer if caller wants that */ ); Assert(left->buf == stack->buffer); + + /* + * If we split the page because we had to adjust the downlink on an + * internal page, while descending the tree for inserting a new tuple, + * then this might no longer be the correct page for the new tuple. The + * downlink to this page might not cover the new tuple anymore, it might + * need to go to the newly-created right sibling instead. Tell the caller + * to walk back up the stack, to re-check at the parent which page to + * insert to. + * + * Normally, the LSN-NSN interlock during the tree descend would also + * detect that a concurrent split happened (by ourselves), and cause us to + * retry at the parent. But that mechanism doesn't work during index + * build, because we don't do WAL-logging, and don't update LSNs, during + * index build. + */ + stack->retry_from_parent = true; } /* |