maria-developers team mailing list archive

[Sergey Vojtovich <svoj@xxxxxxxxxxx>]

Hi Mark,

thanks for this interesting reading. I will also want to have a look at how
much MariaDB is affected by reported regressions and if there are easy ways
to workaround them.

Recently, when I ran single thread benchmarks I observed similar results,
that is parser and optimizer were top CPU time consumers (as well as bus
traffic producers).

Thanks,
Sergey

On Mon, Jan 20, 2014 at 09:32:41AM -0800, MARK CALLAGHAN wrote:
> My analysis was based on benchmarks and described in a few blog posts. This
> is interesting for a few reasons.
> 1) replication is single-threaded at least for a few more years. Eventually
> we will all have the Kristian-inspired idea of getting parallel replication
> apply even when there is only one database shard and that helps some. But
> there are always some workloads that really are single threaded on the
> master and during replication apply.
> 2) fast storage means that IO-bound workloads might be able to get 100,000+
> IOPs on a commodity server. So even when IO-bound we need much higher
> throughput in the past
> 3) At least with public-facing information Oracle doesn't write about this
> topic. Their performance focus is high concurrency.
> 4) RAM per host is much larger so more workloads are not IO bound and
> expect high throughput
> 
> I don't think a complex workload is needed to show the problem. sysbench
> and dbt might be sufficient. linkbench should also be useful to MariaDB.
> 
> http://mysqlha.blogspot.com/2013/09/mysql-41-forever.html
> http://mysqlha.blogspot.com/2013/09/single-threaded-connect-performance.html
> http://mysqlha.blogspot.com/2013/09/mysql-572-single-threaded-performance.html
> http://mysqlha.blogspot.com/2013/05/mysql-56-single-threaded-performance.html
> http://mysqlha.blogspot.com/2013/05/mysql-56-versus-40-for-read-only.html
> http://mysqlha.blogspot.com/2013/04/mysql-56-single-thread-update-only.html
> http://mysqlha.blogspot.com/2013/03/mysql-56-single-threaded-read-only.html
> 
> 
> On Mon, Jan 20, 2014 at 8:18 AM, Sergey Vojtovich <svoj@xxxxxxxxxxx> wrote:
> 
> > Hi Mark,
> >
> > we identified a few single-thread performance issues during the Barcelona
> > meeting. Monty should have them fixed in his private tree. Fixes are quite
> > generic and should improve performance almost in all cases. An exception is
> > bottlenecks specific to certain use cases.
> >
> > Could you send me any relevant information my way if you have it around?
> >
> > Thanks,
> > Sergey
> >
> > On Mon, Jan 20, 2014 at 08:00:45AM -0800, MARK CALLAGHAN wrote:
> > > Are there other goals for single-thread performance regressions? There
> > are
> > > many that have nothing to do with replication code  although almost every
> > > single-threaded replication hurts replication.
> > >
> > >
> > > On Mon, Jan 20, 2014 at 2:54 AM, Axel Schwenke <axel@xxxxxxxxxxxx>
> > wrote:
> > >
> > > > Hi,
> > > >
> > > > for those of you who didn't attend the Barcelona meeting last week,
> > here
> > > > are
> > > > the plans for next steps in benchmarking:
> > > >
> > > > 1. top priority is automatic running of DBT3 for each new release of
> > > > MariaDB-10.0 and MySQL-5.6. Probably also for MariaDB-5.5. I'll send
> > out
> > > > another mail to pinpoint DBT3 conditions (i.e. which table statistics
> > to
> > > > use
> > > > etc.)
> > > >
> > > > 2. multithreaded replication slave is now in a condition that it can
> > and
> > > > should be benchmarked
> > > >
> > > > 3. the problem pointed out by Yoshinori in
> > > >
> > > >
> > http://yoshinorimatsunobu.blogspot.de/2013/12/single-thread-performance-regression-in.html
> > > > must be checked for MariaDB. Monty announced that he will commit a
> > patch
> > > > this week that should help with that problem.
> > > >
> > > > 4. for the NUMA scalability problem, Kristian will try to find the
> > > > definitive reason with profiling tools. Besides that ad-hoc testing of
> > new
> > > > patches from Svoj continues as before.
> > > >
> > > > 5. Galera benchmarking will be done by the Galera team for now.
> > > >
> > > >
> > > > XL
> > > >
> > > > _______________________________________________
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> > > >
> > >
> > >
> > >
> > > --
> > > Mark Callaghan
> > > mdcallag@xxxxxxxxx
> >
> > > _______________________________________________
> > > Mailing list: https://launchpad.net/~maria-developers
> > > Post to     : maria-developers@xxxxxxxxxxxxxxxxxxx
> > > Unsubscribe : https://launchpad.net/~maria-developers
> > > More help   : https://help.launchpad.net/ListHelp
> >
> >
> 
> 
> -- 
> Mark Callaghan
> mdcallag@xxxxxxxxx