Thread: BUG #8274: Wildly insane boolean selectivity estimates
The following bug has been logged on the website: Bug reference: 8274 Logged by: Andrew Gierth Email address: andrew@tao11.riddles.org.uk PostgreSQL version: 9.1.9 Operating system: any Description: The guy on IRC who ran into this one was using 9.1.9, but it seems to still exist in master. The handling of freq_null for estimating IS NOT TRUE/FALSE for boolean columns which are all null or almost all null (enough that analyze doesn't find any non-null values to put in MCV) is completely off in the weeds. Suggested fix at: https://gist.github.com/RhodiumToad/5901567
andrew@tao11.riddles.org.uk writes: > The handling of freq_null for estimating IS NOT TRUE/FALSE for boolean > columns which are all null or almost all null (enough that analyze doesn't > find any non-null values to put in MCV) is completely off in the weeds. Doh, definitely a bit of brain fade there :-( > Suggested fix at: > https://gist.github.com/RhodiumToad/5901567 Seems reasonable, will fix. regards, tom lane