Re: "Hot standby"?

On 08/11/2009 02:52 PM, Robert Haas wrote: <blockquote
cite="mid:603c8f070908111152v452bb1bcj9787f3996a80fe9@mail.gmail.com"type="cite"><pre wrap="">On Tue, Aug 11, 2009 at
2:48PM, Mark Mielke<a class="moz-txt-link-rfc2396E" href="mailto:mark@mark.mielke.cc"><mark@mark.mielke.cc></a>
wrote:</pre><blockquote type="cite"><pre wrap="">I remember this debate from 6 months ago. :-)
 

I prefer not to try and fit square pegs into round holes. Streaming
replication sounds like the best description. It may not be the keywords
that newbies are looking for, but too bad for them. Calling it something
different than what it is, just so that people who don't understand why it
is wrong will have something that approximates the right understanding, is
not a just cause. :-)   </pre></blockquote><pre wrap="">
Uhm, I think you are confused.

Hot Standby = Allow read-only queries on a PostgreSQL server during
archive recovery
Synchronous (or Streaming) Replication = Allow WAL to be streamed on a
byte level rather than copied file-by-file

Hot Standby is not any sort of replication.</pre></blockquote><br /> I don't think I was confused before - but I am
confusednow. :-)<br /><br /> This patch does not provide streaming replication?<br /><br /> Having the standby allow
forread-only queries is a "would be nice" for me, but it's not very useful. I've been monitoring these threads (and
wishingthey were at a level I could participate and contribute on), because I want the ability to have near real time
updatessuch that the standby can become live. "Hot standby" to me means "the slave is as close to up-to-date as
possibleand can potentially take over at any time in a near instance." This *implies* some sort of streaming
replication(byte level rather than file-by-file) rather than waiting for WAL logs to become full and shipped.<br /><br
/>If this patch doesn't give me near real time replication, then I am confused about why I would want it at all.
pg_standbyalready gives the ability to do replication on a per completed WAL log file basis.<br /><br /> Cheers,<br />
mark<br/><br /><pre class="moz-signature" cols="72">-- 
 
Mark Mielke <a class="moz-txt-link-rfc2396E" href="mailto:mark@mielke.cc"><mark@mielke.cc></a>
</pre>