Hey, I upgraded my pg9.6 cluster to pg11.2. As it seems after the upgrade the duration of the same flow in my application raised from 13 minutes to 19 minutes.
The test I did : 1.reset pg_stat_statements 2.run the applicative flow 3.collect everything from pg_stat_statements I did this test on the env before the upgrade and after the upgrade. I took the sum of the total_time in pg_stat_statements and sumed it up. my env settings : 60GB RAM 16CPU regular HD postgresql.conf settings : max_wal_size = 2GB min_wal_size = 1GB wal_buffers = 16MB checkpoint_completion_target = 0.9 checkpoint_timeout = 30min standard_conforming_strings = off max_locks_per_transaction = 5000 max_connections = 500 random_page_cost = 4 deadlock_timeout = 5s shared_preload_libraries = 'pg_stat_statements' track_activity_query_size = 32764 log_directory = 'pg_log' enable_partitionwise_join = on enable_partitionwise_aggregate = on max_worker_processes = 16 # (change requires restart) max_parallel_maintenance_workers = 8 # taken from max_parallel_workers max_parallel_workers_per_gather = 8 # taken from max_parallel_workers max_parallel_workers = 16 maintenance_work_mem = 333MB work_mem = 60MB shared_buffers = 15129MB effective_cache_size = 30259MB The conf file was used in 9.6 (without all the new parallel settings). Now the same queries run in both tests because it was the same flow. I will be happy to hear if u have any ideas without involving any queries changes..
