On Wed, Apr 17, 2019 at 11:52:44PM -0400, Gunther wrote:
> Hi guys. I don't want to be pushy, but I found it strange that after so much
Were you able to reproduce the issue in some minimized way ? Like after
joining fewer tables or changing to join with fewer join conditions ?
On Thu, Apr 18, 2019 at 05:21:28PM +0200, Tomas Vondra wrote:
> As for the issue - I think the current hypothesis is that the data
> distribution is skewed in some strange way, triggering some unexpected
> behavior in hash join. That seems plausible, but it's really hard to
> investigate without knowing anything about the data distribution :-(
>
> It would be possible to do at least one of these two things:
>
> (a) export pg_stats info about distribution of the join keys
For starts, could you send the MCVs, maybe with some variation on this query ?
https://wiki.postgresql.org/wiki/Slow_Query_Questions#Statistics:_n_distinct.2C_MCV.2C_histogram
Justin
