I noticed this on PG 10 recently, while I agree it is an obsolete version. pg_blocking_pids() showed that one of the CIC on a Table is blocked by a CIC on another Table.
I saw them both created over a period of time after which I doubted what was reported by pg_blocking_pids(). As it was PG 10, I could not see the phase of CIC and interestingly no wait events. Anyways, PG 10 is unsupported but I would try it on a newer version. Curious to understand why this would have happened. Regards, Avi Vallarapu. On Sun, Oct 15, 2023 at 2:35 PM Konstantin Knizhnik <knizh...@garret.ru> wrote: > One our customer complains that he spawned two `create index concurrently` > for two different tables and both stuck in "waiting for old snapshots". > I wonder if two CIC can really block each other in ` > WaitForOlderSnapshots`? > I found the similar question in hacker archive: > > > https://www.postgresql.org/message-id/flat/MWHPR20MB1421AEC7CEC67B159AC188F6A19A0%40MWHPR20MB1421.namprd20.prod.outlook.com > > but it is quite old (2016). Was the problem fixed since that time? And if > not, why there it is not mentioned in CIC documentation that performing > several CIC in parallel can cause "deadlock"? > > Thanks in advance, > Konstantin > -- Regards, Avinash Vallarapu +1-902-221-5976
