rihad wrote: > > Sorry, I just decreased work_mem back to 256MB, reloaded, and > > instantly started seeing 82mb temp file creation, not 165mb as was > > usual with work_mem=512MB. > > > > So it indeed was applied immediately. > > Really weird figures ) > > Increased work_mem to 768MB and start seeing temp file creation log > entries 331MB in size. > > Bizzare ) It looks like the bigger it gets, the bigger temp files > are > created. > > Why not decrease it to 64mb then... Temporary files are created whenever the data is estimated to not fit into "work_mem". So it is unsurprising that you see bigger temporary files being created if you increase "work_mem". Big temporary files will also be created when "work_mem" is small, but maybe they got lost in the noise of the smaller files. You should have noticed that fewer files are created when you increase "work_mem". Another thing to notice is that the temporary files use another, more compact format than the data in memory, so you need to increase "work_mem" to more than X if you want to avoid temporary files of size X. Yours, Laurenz Albe -- Cybertec | https://www.cybertec-postgresql.com
