Tuesday, September 9, 2008

Re: [HACKERS] Synchronous Log Shipping Replication


Dimitri Fontaine wrote:
> Exactly the point. The process is now already waiting in all cases, so maybe
> we could just force waiting some WALSender signal before sending the fsync()
> order, so we now have Group Commit.

A single process can only wait on either fsync() or on select(), but not
on both concurrently, because both syscalls are blocking. So mixing
these into a single process is an inherently bad idea due to lack of

I fail to see how log shipping would ease or have any other impact on a
Group Commit feature, which should clearly also work for stand alone
servers, i.e. where there is no WAL sender process.


Markus Wanner

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