Re: Controlling Load Distributed Checkpoints

Heikki Linnakangas <heikki@enterprisedb.com> writes:
> Thinking about this whole idea a bit more, it occured to me that the 
> current approach to write all, then fsync all is really a historical 
> artifact of the fact that we used to use the system-wide sync call 
> instead of fsyncs to flush the pages to disk. That might not be the best 
> way to do things in the new load-distributed-checkpoint world.

> How about interleaving the writes with the fsyncs?

I don't think it's a historical artifact at all: it's a valid reflection
of the fact that we don't know enough about disk layout to do low-level
I/O scheduling.  Issuing more fsyncs than necessary will do little
except guarantee a less-than-optimal scheduling of the writes.
        regards, tom lane