Re: Fsync on/off For Various Filesystems/Platforms (Ending Note) - Mailing list pgsql-general

From Tom Lane
Subject Re: Fsync on/off For Various Filesystems/Platforms (Ending Note)
Date
Msg-id 4146.1015688278@sss.pgh.pa.us
Whole thread Raw
In response to Fsync on/off For Various Filesystems/Platforms (Ending Note)  (Mark kirkwood <markir@slingshot.co.nz>)
List pgsql-general
Mark kirkwood <markir@slingshot.co.nz> writes:
> I forgot to mention :
> 1) the test involved usng copy to load the rows !

Still not much help.  Was it a single COPY command, or a bunch of them?

The fsync overhead is (and always has been) a per-transaction cost,
so a benchmark that gives you no idea how many transactions were
committed isn't much help.  Also, if there was only one transaction
commit in your 5-minute benchmark run, then I can see why fsync would
be pretty irrelevant ... try something with one commit per inserted
row if you want to see a bigger penalty ...

            regards, tom lane

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