Artem Tomyuk wrote: > The questions is how to avoid creating temp files on disk? > > The work_mem parameter set to 1600 Megabytes, but on logs i still can see the messages like: > LOG: temporary file: path "base/pgsql_tmp/pgsql_tmp7905.2", size 865869824
Temporary files on disk are smaller than the memory required for the corresponding in-memory operation, which explains why the size of the temporary file is less than 1600 MB.
You can either try to increase work_mem or change the query so that it does not perform such large operations.
Probably better off trying to optimize your query vs large work_mem values like that.
Recommend reading over https://wiki.postgresql.org/wiki/Tuning_Your_PostgreSQL_Server to learn what work_mem actually does (and a bunch of other great tuning info). You could run yourself out of memory really fast if that's your default work_mem setting.
-- Keith Fiske Database Administrator OmniTI Computer Consulting, Inc. http://www.keithf4.com