[Bucardo-general] Swap replication latency

Alex Balashov abalashov at evaristesys.com
Fri May 6 01:30:17 UTC 2011

P.S.   I think the reason it can't catch up at a normal pace is because 
it takes me about ~5 minutes to add the table to the sync, run the 'add 
sync' command (which entails a validate_sync()), and then start it.

During that time, as many as several thousand net deltas happen, and so 
in order to catch up Bucardo would have to operate at a transactional 
throughput that is fast enough to both catch up to the changes 
accumulated during the sync reinitialisation + stay on top of new ones 
at the same pace.  Evidently it cannot do that, at least as tuned by 

So, is there a way I can turbocharge it?

On 05/05/2011 09:27 PM, Alex Balashov wrote:

> I've troubleshot this some more on our side by process of elimination of
> synced tables, and what I found is that the sync time trends back toward
> a normal 5-6 sec when all tables that are modified at a high volume are
> excluded.
> As a test, I added one of the high-volume tables, which was doing
> roughly ~2000 UPDATEs every 10 minutes, and maybe 300 INSERTs during the
> same time frame.  Bucardo fell way behind to a 11+ minute sync run time,
> and the delta table started blowing up.
> These statements do not take any appreciably long time to run.  Yeah,
> they're not the fastest thing ever, but the point is that both database
> servers can easily handle the load.  So the bottleneck really is
> Bucardo, not the target database server;  the hardware is identical, and
> the target server's load average constantly hangs around ~0.01, and the
> source database server isn't exactly breaking a sweat either.  We have
> Postgres set to log queries over 15 ms and are getting hardly any
> complaints.
> Thus, I can only come to the conclusion that Bucardo is not spinning
> nearly hard enough.
> So the question is, what--if any--parameters can I tweak to make
> Bucardo's transactional throughput faster?  Preferably several times
> faster.  Is it even possible, or is this basically a low-speed
> replication system and there is not much that can be done here?
> Thanks,

Alex Balashov - Principal
Evariste Systems LLC
260 Peachtree Street NW
Suite 2200
Atlanta, GA 30303
Tel: +1-678-954-0670
Fax: +1-404-961-1892
Web: http://www.evaristesys.com/

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