1. Why do we lock all posting tree pages, even though they all represent the
same value? Isn't it enough to lock the root of the posting tree?
2. Why do we lock any posting tree pages at all, if we lock the entry tree page
anyway? Isn't the lock on the entry tree page sufficient to cover the key value?
3. Why do we *not* lock the entry leaf page, if there is no match? We still need
a lock to remember that we probed for that value and there was no match, so that
we conflict with a tuple that might be inserted later.
At least #3 is a bug. The attached patch adds an isolation test that
demonstrates it. #1 and #2 are weird, and cause unnecessary locking, so I think
we should fix those too, even if they don't lead to incorrect results.
I can't find a hole here. Agree.
I took a stab at fixing those issues, as well as the bug when fastupdate is
turned on concurrently. Does the attached patch look sane to you?
I like an idea use metapage locking, thank you. Patch seems good, will you push
Teodor Sigaev E-mail: teo...@sigaev.ru