Re: Group Commits Vs WAL Writes

>
> commit_delay exists to artificially increase the window in which the
> leader backend waits for more group commit followers. At higher client
> counts, that isn't terribly useful because you'll naturally have
> enough clients anyway, but at lower client counts particularly where
> fsyncs have high latency, it can help quite a bit. I mention this
> because clearly commit_delay is intended to trade off latency for
> throughput. Although having said that, when I worked on commit_delay,
> the average and worse-case latencies actually *improved* for the
> workload in question, which consisted of lots of small write
> transactions. Though I wouldn't be surprised if you could produce a
> reasonable case where latency was hurt a bit, but throughput improved.

Thanks for your reply.

The logic says that latency will be hit when commit_delay is applied,
but I am really interested in why we get an improvement instead.

Can small writes be the reason?

Regards,

Atri


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Regards,

Atri
l'apprenant