Tom Lane wrote: > Bruce Momjian <[EMAIL PROTECTED]> writes: > > Pavan Deolasee wrote: > >> When following a HOT-update chain from the index fetch, if we notice that > >> the root tuple is dead and it is HOT-updated, we try to prune the chain to > >> the smallest possible length. To do that, the share lock is upgraded to an > >> exclusive lock and the tuple chain is followed till we find a > >> live/recently-dead > >> tuple. At that point, the root t_ctid is made point to that tuple. In order > > > I assume you meant recently-dead here, rather than live/recently-dead, > > because we aren't going to change live ctids, right? > > "Recently dead" means "still live to somebody", so those tids better not > change either. But I don't think that's what he meant. I'm more > worried about the deadlock possibilities inherent in trying to upgrade a > buffer lock. We do not have deadlock detection for LWLocks.
I am guessing he is going to have to release the lock, then ask for an exclusive one. -- Bruce Momjian <[EMAIL PROTECTED]> http://momjian.us EnterpriseDB http://www.enterprisedb.com + If your life is a hard drive, Christ can be your backup. + ---------------------------(end of broadcast)--------------------------- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
