Kenneth Marshall <ktm@xxxxxxxx> writes: > On Fri, Jun 19, 2020 at 04:11:10PM -0400, Tom Lane wrote: >> The reason for such an estimation error usually is that the maximum >> join key values recorded in pg_stats are off: the join side that is >> going to be exhausted is the one with the smaller max join key. >> "articles" seems to be small enough that the stats for it will be >> exact, so your problem is a poor estimate of the max value of >> objectcustomfieldvalues.objectid. You might try raising the statistics >> target for that table. Or maybe it's just that ANALYZE hasn't been >> done lately on one table or the other? > Thank you for the information and suggestion. I tried bumping the statistics for the > objectcustomfieldvalues.objectid column to 2k, 5k and 10k followed by an analyze and > the query plan stayed the same. I also analyzed the article table > repeatedly and their was no change in the plan. The table articles only has 151 rows > while the objectcustomfieldvalues table has 19031909 rows. Any idea > about why it is so far off? What's the actual maximum value of objectcustomfieldvalues.objectid, and how does that compare to the endpoint value in the pg_stats histogram for that column? If you've got one outlier in the table, it might get missed by ANALYZE. regards, tom lane
