maria-discuss team mailing list archive

["J. Cassidy" <sean@xxxxxxxxxxxx>]

Privet Sergey,

do not think I have a problem with my config(s).

I am not on the machine at the moment. From memory, with 16 Cores / 32
VCPU, 64 GB memory, buffer pools, logs etc. tailored to this configuration, the
TPS rate is

64 threads - R/O 73K R/W 26K
128 threads - R/O 71K R/W
23K.

I am putting the DB in RAM of course to obviate I/O issues. I am
interested in seeing what is happening with the CPU caches and nest..

NMON tells me that for the R/O runs I have approximately 85% User, 12-14% System
and the rest Idle - this stays consistent throughout the run (300 seconds R/O, 600
seconds R/W)  which is reasonable.

On the R/W runs, NMONs CPU
usage display shows that some CPUs are barely firing, or only intermittently and
the granularity I had with R/O is gone. This would seem to tie in with what I see
in the MariaDB log - headwinds, violent storms and deadlocks.

Any
further information you require, please let me know.



Regards,


JC

Hi!

I just tried this on x86:
40 threads against single table having 10k rows.
No deadlocks, "tps:
12372.40, reads: 173219.52, writes: 49490.51".

This is with latest
snapshot of 10.1 and sysbench 1.0.

I believe you shouldn't see
deadlocks on such a big data set. Probably
something is wrong with your
configs?

Regards,
Sergey

On Thu, Jun 08, 2017 at
04:51:31PM +0200, J. Cassidy wrote:
>
>
> Hello Mark,
>
> appreciate the reply.
>
> The OLTP table size
and
> OLTP size give me a DB size of appx 12GB. This is what I want. I
have in the
> meantime, looked at some older logs and see that whatever
amount of threads I
> specify (8, 16,32, 64 or 128), the deadlock messages
are still surfacing in the
> R/W phase
> of Sysbench. I even
dropped in two different MariaDB release levels
> (10.0.19, 10.1.24) to
see whether it would make a difference, deadlock still
> there. I am using
Sysbench 0.5 for these tests.
> I am currently using MariaDB
>
10.1.24 - built directly on the machine. S390x by the way, but the problem is
> also
> occuring on an X86-64 box.
>
> Regards,
>
>
> JC
>
>
>
> I run
sysbench frequently with MySQL
> (not MariaDB yet) and don't
recall ever seeing this error. But I use much
> larger values for
--oltp-table-size. You used 85937 and I use 1M or larger.
> Maybe
> there is too much data contention with smaller tables, even if a large
number of
> tables is used (128 in your case). I use a smaller number of
tables - between 4
> and 20. On Thu, Jun 8, 2017 at 12:48 AM, J.
Cassidy sean@xxxxxxxxxxxx> wrote:
> Hello all,
>
>
> have used Sysbench extensively to test MariaDB CPU load factors between
various
> architectures.
>
> I am noticing massive amounts
of "[ERROR] mysqld:
> Deadlock found when trying to get lock; try
restarting transaction" in the
> MariaDB error log during the R/W
phase. The Sysbench R/W TPS rates are still
> respectable for my purposes,
but how do I
> correct this condition?? Can I
> ignore this / must
live with it?
> I have tried three different MariaDB
> releases
(10.0.19, 10.1.12, 10.1.24) to narrow things down, but this message (x
>
1000's) is happening across all releases in the Sysbench R/W phase.
>
> Here is the Sysbench command that drives the workload against
MariaDB -
>
> sysbench --test=lua/oltp.lua --oltp_tables_count=128
--oltp-table-size=85937
> --rand-seed=42 --rand-type=uniform
--num-threads=128 --oltp-read-only=off
> --report-interval=2
--mysql-socket=/var/lib/mysql/mysql.sock --max-time=201
> --max-requests=0
--mysql-user=root --percentile=99 run
>
> Would anyone
>
have a tip / idea /pointer?
>
>
> Regards,
>
>
> JC
>
>
> John Cassidy
>
>
Obere Bühlstrasse 21
> 8700 Küsnacht
> (ZH)
>
Switzerland / Suisse / Schweiz
>
>
> Mobile: +49 152
58961601 (Germany)
> Mobile: +352 621 577 149 (Luxembourg)
>
Mobile: +41 78 769 17 97 (CH)
> Landline: +41 44 509 1957
>
> http://www.jdcassidy.eu
>
> "Aut viam inveniam aut
> faciam" - Hannibal.
>
_______________________________________________
> Mailing list:
https://launchpad.net/~maria-discuss
> Post to     :
> maria-discuss@xxxxxxxxxxxxxxxxxxx
> Unsubscribe :
https://launchpad.net/~maria-discuss
> More help   :
https://help.launchpad.net/ListHelp
>    --Mark
Callaghan
> mdcallag@xxxxxxxxx
>
> John Cassidy
>
> Obere Bühlstrasse 21
> 8700
> Küsnacht
(ZH)
> Switzerland / Suisse / Schweiz
>
>
>
Mobile:
> +49 152 58961601 (Germany)
> Mobile: +352 621 577 149
(Luxembourg)
> Mobile:
> +41 78 769 17 97 (CH)
> Landline:
+41 44 509 1957
>
> http://www.jdcassidy.eu
>
>
"Aut viam inveniam aut faciam" -
> Hannibal.

>
_______________________________________________
> Mailing list:
https://launchpad.net/~maria-discuss
> Post to :
maria-discuss@xxxxxxxxxxxxxxxxxxx
> Unsubscribe :
https://launchpad.net/~maria-discuss
> More help :
https://help.launchpad.net/ListHelp




John Cassidy

Obere Bühlstrasse 21
8700 Küsnacht (ZH)
Switzerland /
Suisse / Schweiz


Mobile: +49 152 58961601 (Germany)
Mobile:
+352 621 577 149 (Luxembourg)
Mobile: +41 78 769 17 97 (CH)
Landline:
+41 44 509 1957

http://www.jdcassidy.eu

"Aut viam
inveniam aut faciam" - Hannibal.