Re: Synchronization levels in SR

Simon Riggs wrote:
> On Wed, 2010-05-26 at 18:52 +0900, Fujii Masao wrote:
> 
> > I guess that dropping the support of #3 doesn't reduce complexity
> > since the code of #3 is almost the same as that of #2. Like
> > walreceiver sends the ACK after receiving the WAL in #2 case, it has
> > only to do the same thing after the WAL flush.
> 
> Hmm, well the code for #3 is similar also to the code for #4. So if you
> do #2, its easy to do #2, #3 and #4 together.
> 
> The comment is about whether having #3 makes sense from a user interface
> perspective. It's easy to add options, but they must have useful
> meaning.

If the slave is runing read-only queries, #3 is the most reliable option
withouth delaying the slave, so there is a usecase for #3.

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com