Hi, On 2018-01-03 02:20:14 +0000, Alvaro Herrera wrote: > Fix deadlock hazard in CREATE INDEX CONCURRENTLY > > Multiple sessions doing CREATE INDEX CONCURRENTLY simultaneously are > supposed to be able to work in parallel, as evidenced by fixes in commit > c3d09b3bd23f specifically to support this case. In reality, one of the > sessions would be aborted by a misterious "deadlock detected" error. > > Jeff Janes diagnosed that this is because of leftover snapshots used for > system catalog scans -- this was broken by 8aa3e47510b9 keeping track of > (registering) the catalog snapshot. To fix the deadlocks, it's enough > to de-register that snapshot prior to waiting. > > Backpatch to 9.4, which introduced MVCC catalog scans. > > Include an isolationtester spec that 8 out of 10 times reproduces the > deadlock with the unpatched code for me (Álvaro).
The isolation test doesn't appear to be fully stable: https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=baiji&dt=2018-01-03%2003%3A00%3A01 Greetings, Andres Freund
