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Fwd: Re: Performace issue with insert

 

Am 27.01.2016 11:33, schrieb Peter Laursen:
> "We have notice that the write performance decreases with
> time, start of the month good, end of the month bad."
> 
> Do you happen to partition BY MONTH? if so it looks like the more the
> latest partition grows the slower it becomes.I am no expert in this but I
> think you should post the CREATE TABLE for this table. You should also tell
> the exact MariaDB and MySQL versions you have tried ("SELECT version();").

yes, sorry the partitons are by month
the mariadb version we tried were 5.1.62 and 10.1.10 compared with mysql 5.1.53

I do not think that will be helpful since the table is simple and exactly equal in
both cases:

2 primaries + ~30 Entries

Partition are created like this:
 ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_german2_ci
/*!50100 PARTITION BY RANGE (TO_DAYS(time_stamp))
(PARTITION im1_199801 VALUES LESS THAN (729786) ENGINE = MyISAM,
 PARTITION im1_199802 VALUES LESS THAN (729814) ENGINE = MyISAM,
 PARTITION im1_199803 VALUES LESS THAN (729845) ENGINE = MyISAM,
 PARTITION im1_199804 VALUES LESS THAN (729875) ENGINE = MyISAM,
 PARTITION im1_199805 VALUES LESS THAN (729906) ENGINE = MyISAM,
 PARTITION im1_199806 VALUES LESS THAN (729936) ENGINE = MyISAM,

and many more ...

my guess:
The difference is considerable. I suspect that mysql does cache a number
of inserts while maria is writing every entry, something on that line.

re,
 wh

> 
> -- Peter
> -- not a MariaDB person
> 
> On Wed, Jan 27, 2016 at 11:27 AM, walter harms <wharms@xxxxxx> wrote:
> 
>> Hello list,
>> i have a strange problem with inserts.
>> The tables is large (time series data) and has a
>> lot of partitions, engine is IMMODB.
>> We have notice that the write performance decreases with
>> time, start of the month good, end of the month bad.
>>
>> The same behavier is the lasted version of mariadb.
>> But when i replace mariadb with mysql the problems vanishes
>> (so its not a hardware issue). I suspect that it is a caching
>> problem but a comparison of the configs did not give a hint.
>> Anyone an idea what may cause the effect ?
>>
>>
>> re,
>>  wh
>>
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> 


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