Reconsider nbtree page deletion assertion. Commit 624686abcf8 added an assertion that verified that _bt_search successfully relocated the leaf page undergoing deletion. Page deletion cannot deal with the case where the descent stack is to the right of the page, so this seemed critical (deletion can only handle the case where the descent stack is to the left of the leaf/target page). However, the assertion went a bit too far.
Since only a buffer pin is held on the leaf page throughout the call to _bt_search, nothing guarantees that it can't have split during this small window. And if does actually split, _bt_search may end up "relocating" a page to the right of the original target leaf page. This scenario seems extremely unlikely, but it must still be considered. Remove the assertion, and document how we cope in this scenario. Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/67b0b2dbf947c2308050e49b4591a4bb0e9650fd Modified Files -------------- src/backend/access/nbtree/nbtpage.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-)
