Re: checkpointer continuous flushing - V18 - Mailing list pgsql-hackers

From Fabien COELHO
Subject Re: checkpointer continuous flushing - V18
Date
Msg-id alpine.DEB.2.10.1603102332220.18837@sto
Whole thread Raw
In response to Re: checkpointer continuous flushing - V18  (Andres Freund <andres@anarazel.de>)
Responses Re: checkpointer continuous flushing - V18  (Andres Freund <andres@anarazel.de>)
List pgsql-hackers
[...]

> I had originally kept it with one context per tablespace after 
> refactoring this, but found that it gave worse results in rate limited 
> loads even over only two tablespaces. That's on SSDs though.

Might just mean that a smaller context size is better on SSD, and it could 
still be better per table space.

> The number of pages still in writeback (i.e. for which sync_file_range
> has been issued, but which haven't finished running yet) at the end of
> the checkpoint matters for the latency hit incurred by the fsync()s from
> smgrsync(); at least by my measurement.

I'm not sure I've seen these performance... If you have hard evidence, 
please feel free to share it.

-- 
Fabien.



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