Re: Synchronous Log Shipping Replication

Hi,

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 
parallelism.

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.

Regards

Markus Wanner