Dmitry Koterov dmitry at koterov.ru
Mon May 14 06:42:38 PDT 2007
>
> > >> So, if anybody reads from sl_log_status, it blocks until anything is
> > >written
> > >> to sl_log_status.
> > >It sounds like a way to make everything a lot slower.
> > Why? Where is the slowdown?
> If you have many slaves trying to read, they're all blocked.  This is
> effectively going to single-thread all the replicas.  It will be
> slower.

Hmmm... But in postgres read operations never blocks other operations (by
default) because of versioning. So, while all the replicas are blocked
waiting for a new event, they are still able to process a lot of read
queries coming from the site.

Or you mean that after unblocking ALL the replicas will simultaneously begin
to read new events from the Master and slow him down greatly? Please
detalize, it is not clear enough for me yet...

Thanks.
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