[prev in list] [next in list] [prev in thread] [next in thread] 

List:       pdns-users
Subject:    Re: [Pdns-users] ddns performance of pdns
From:       Thomas Mieslinger <miesi () pc-h ! de>
Date:       2016-02-25 20:19:44
Message-ID: 56CF61E0.6070209 () pc-h ! de
[Download RAW message or body]

Hi altogether,

thank you for sharing your thoughts.

I did some testing. The records table has around 115k rows. When I send 
single updates for a zone that has ~20 rows (out of the 100k) I get 
about 100 updates per second (what would be sufficient in my use case). 
When the zone to be updated has 80k records I only get 1 ddns update per 
second.

I activated the mysql query log and analyzed (explain) them. All 
statements use the indexes and, when running them individually, they 
perform well.

I will review my mysql configuration if there is optimization possible. 
Maybe the query cache is to small or something else.

Cheers

Thomas

Am 25.02.2016 um 18:25 schrieb Ruben d'Arco:
> On Thu, Feb 25, 2016 at 07:54:26AM -0600, ktm@rice.edu wrote:
> > On Thu, Feb 25, 2016 at 12:01:19PM +0100, Thomas Mieslinger wrote:
> > > Hi,
> > > 
> > > today I wanted to migrate my ddns master from bind to pdns. 3 DHCP
> > > Servers sent a about 50 updates per second to the pdns 3.4.8 and
> > > only one or two updates per second could be successfully commited to
> > > the database.
> > > 
> > > All failed transactions rolled back after trying to edit the SOA record.
> > > 
> > > I'm using 5.1.73-log MySQL Community Server.
> > > 
> > > I'm using REPEATABLE-READ transaction-isolation and
> > > 
> > > distributor-threads=2
> > > receiver-threads=10
> > > 
> > > as pdns performance settings.
> > > 
> > > I tried to disable SOA-EDITs with domainmetadata
> > > 
> > > SOA-EDIT-DNSUPDATE   | SOA-EDIT
> > > SOA-EDIT             | NONE
> > > 
> > > but that didn't change anything.
> > > 
> > > What DDNS performance do you get from your pdns instances with which
> > > settings?
> > > 
> > > Thanks Thomas
> > 
> > Hi Thomas,
> > 
> > You will need to investigate your DB performance. Turn on query logging
> > and slow query logging. Also check system I/O stats to see if you have
> > a bottleneck there. We are just getting started on adding a DDNS component
> > to our network so I do not have any firsthand experience with it and the
> > queries it uses. Good luck in your hunt for the bottleneck.
> > 
> > Regards,
> > Ken
> 
> 
> Just to add to this, there is a lock for every update message. This is to avoid 2 \
> update messages from causing some transactional issues. There's also a comment \
> above that lock that the lock might should be placed per zone, allowing multiple \
> zones to be updated at the same time. 
> When i did some testing on this, it seemed that this was the limiting factor. It's \
> just not fast if 1 update needs to wait for the other to be completed. But, at the \
> time, i didn't check if this could be done better. 
> You mentioned that you have 3 dhcp servers - i'm assuming they all update the same \
> zone? 
> Regards,
> 	Ruben
> 
> _______________________________________________
> Pdns-users mailing list
> Pdns-users@mailman.powerdns.com
> http://mailman.powerdns.com/mailman/listinfo/pdns-users
> 
_______________________________________________
Pdns-users mailing list
Pdns-users@mailman.powerdns.com
http://mailman.powerdns.com/mailman/listinfo/pdns-users


[prev in list] [next in list] [prev in thread] [next in thread]