Patrick Krecker <patrick@xxxxxxxxxxxx> writes: > Hello everyone -- We received a strange error today on our production write > master. During a routine maintenance script, we got the following error: > "ERROR: cache lookup failed for aggregate 5953992" > I think I found the culprit. We have a cron script that (among other > things) recreates the aggregate function array_cat_aggregate()once every > minute. Um. Why's it do that? > My guess is that a) transactions do not guarantee a snapshot of > custom functions and b) we got unlucky and the aggregate was deleted during > the execution of the UPDATE. Yeah, there's no guarantee that dropping the aggregate wouldn't leave a window for this type of failure. 9.4 might be a little better about this because it doesn't use SnapshotNow for catalog fetches anymore, but I think you'd still be at some risk. > Here is the query that produced the error: It'd be more interesting to see what the cron script was doing to the aggregate definition. regards, tom lane
