track_commit_timestamp server parameter in Azure Database for PostgreSQL flexible server

Naveen Kumar Kakarla (Quadrant Resource) 181 Reputation points
2024-05-15T11:17:18.27+00:00

I see that track_commit_timestamp server parameter is disabled by default in Azure Database for PostgreSQL flexible server, I would like to know if there is any performance issue if I enable it.

Azure Database for PostgreSQL
Accepted answer
  1. GeethaThatipatri-MSFT 28,852 Reputation points Microsoft Employee
    2024-05-28T16:05:52.12+00:00

    @Naveen Kumar Kakarla (Quadrant Resource) Biggest cost of enabling it, is that it requires a server restart. Each committed transaction requires 10 bytes in the pg_commit_ts SLRU. In extremely busy systems, contention on that SLRU cache could be observed.

    A recent commit made by Álvaro Herrera which has been merged in REL_17_BETA1 branch of the OSS project, introduced several improvements that aim to alleviate performance of subsystems that relied on these SLRUs. No matter what theory can explain about potential impact of enabling this, you should definitely run some collected activity from real-life workload with it disabled, and run it again with it enabled to compare both.

    I hope this information helps to understand on Performance and cost.

    Regards

    Geetha

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