Subject Re: after 2.1 to 2.5 migration, nbackup seems to slow operations unusually
Author Dmitry Yemanov
11.07.2013 2:07, unordained wrote:

> For the most part, things are okay, but when nbackup is running (level-2
> backups
> every hour, takes about 10 minutes), I'm seeing something I haven't
> historically
> seen: concurrent queries take enormously longer to complete than usual.
> I'm used
> to a little bump in the average with no significant outliers, but now
> I'm seeing
> stuff hang as long as 4 or 5 minutes, that used to maybe take 200ms
> extra during
> backups. Once the backup is finished, it all goes back to normal. It
> doesn't
> seem to force queries to wait until the backup is finished, it just
> delays them
> a lot. (Doesn't seem to be right when it merges the delta file back in,
> which
> I've noticed before does tend to nearly freeze everything.) I see
> slowness in
> getting connections / starting transactions, in reads, writes... it's
> not just
> one aspect.

Out of curiosity, did you try playing with -D ON/OFF modes for nbackup?
If so, does it make any difference?