Hi all, we are in the process of migrating postgresql 9.1 to 9.6 and we encounter a memory issues with 9.6 - one of our procedure consumed all free memory (~8GB) of the testing server (and make it to swap), there was never such problem with 9.1. After some testing we found out that it is caused by user-defined aggregate array_accum (defined as in postgres documentation). We rewrote this procedure using built-in array_agg function and it seems to work better (at least it is usable). Anyway during the troubleshooting we did simple memory usage comparison of 9.1 and 9.6 of usage array_accum and array_agg. We run following query on same hw (machine has 10GB of RAM) and same memory postgresql settings and watched for memory usage of postgresql backend process (with ps -o vsize,rss,%mem,size) postgresql.conf: shared_buffers = 4GB temp_buffers = 8MB work_mem = 1GB maintenance_work_mem = 1GB For array_accum: SELECT array_accum(n) from generate_series(1,100000000) n GROUP BY n % 100000 Peak memory usage of the backend process was On 9.1 - 1.7GB On 9.6 - 4.5GB Same using array_agg: SELECT array_agg(n) from generate_series(1,100000000) n GROUP BY n % 100000 Peak memory usage of the backend process was On 9.1 - 3.3GB On 9.6 - 2.7GB My question is if there were any changes between 9.1 and 9.6 which would explain described behavior or could there be problem somewhere in our configuration (e.g. missed some new settings) or at last problem is with the test itself and behavior is correct. Any advice or explanation would be appreciated. Regards Jiri -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
