Re: Proposal for 9.1: WAL streaming from WAL buffers

Stefan Kaltenbrunner <stefan@kaltenbrunner.cc> writes:
> hmm not sure that is what fujii tried to say - I think his point was 
> that in the original case we would have serialized all the operations 
> (first write+sync on the master, network afterwards and write+sync on 
> the slave) and now we could try parallelizing by sending the wal before 
> we have synced locally.

Well, we're already not waiting for fsync, which is the slowest part.
If there's a performance problem, it may be because FADVISE_DONTNEED
disables kernel buffering so that we're forced to actually read the data
back from disk before sending it on down the wire.

			regards, tom lane