Performance regression related to parallel execution

Hello, We noticed that the following SQL queries are running 3 times slower on the latest version of PostgreSQL. Here’s the time taken to execute them on older (v9.5.16) and newer versions (v11.2) of PostgreSQL (in milliseconds): +---++-+-+---+

Performance regressions found using sqlfuzz

the same setup that we described before: https://www.postgresql.org/message-id/BN6PR07MB3409922471073F2B619A8CA4EE640%40BN6PR07MB3409.namprd07.prod.outlook.com - As Andrew mentioned before, we increased default work_mem to 128MB Best regards, Jinho Jung QUERY 5 EXPLAIN ANALYZE select ref_0