Consecutive Query Executions with Increasing Execution Time

Hi all, I am running TPC-H on recent postgresql (12.0 and 12.1). On some of the queries (that may involve parallel scans) I see this interesting behavior: When these queries are executed back-to-back (sent from psql interactive terminal), the total execution time of them increase monotonically. I

Re: Consecutive Query Executions with Increasing Execution Time

: the second starts before the > first ends, and so on. With a short wait in between you ensure sequential > execution. Notice that you also have the overhead of concurrent psql... > > Sounds normal to me. > > Best regards > Olivier > > > On Mon, Dec 16, 2019, 07:00 Shijia

Re: Consecutive Query Executions with Increasing Execution Time

quot;actual time" of the Parallel Index Only Scan increased from 114ms to 143ms. The same holds for other examples that involve Parallel Seq Scan. Thanks, Shijia On Mon, Dec 16, 2019 at 7:25 AM Laurenz Albe wrote: > On Sun, 2019-12-15 at 23:59 -0600, Shijia Wei wrote: > > I am run

Re: Consecutive Query Executions with Increasing Execution Time

Hi everyone! Thanks a ton for this brilliant discussion here! It turned out that Nicolas was correct! I found that the CPU was broken and not spinning at all. With consecutive parallel query execution, the CPU temperature hits 100C almost immediately after 1 or 2 iterations. So the processor start