[horde] Horde ActiveSync - every few seconds disk write of the mysql database

[Samuel Wolf]

Zitat von Michael J Rubinsky <mrubinsk at horde.org>:

> Quoting Samuel Wolf <samuel at sheepflock.de>:
>
>> Hi,
>>
>> I wondering why my small home Horde server has every few seconds a  
>> ssd access.
>> Find out after some debugging with top/iostat/dstat it is a write  
>> operation of the database.
>>
>> Nobody use the Horde Web interface at this time, only Smartphones  
>> via ActiveSync are connected. As soon I stop the apache, the write  
>> access stop as well.
>>
>> Is there something with ActiveSync which need every few seconds a  
>> insert/update in the database?
>
> There are a number of places where we need to save state to storage  
> in ActiveSync. The most frequent cause of this would be during the  
> start of various types of PING and SYNC requests where we save a  
> timestamp and possibly other data (depending on the type of SYNC  
> request). This is needed to prevent race conditions since clients  
> may (and often do) initiate new SYNC/PING requests while a previous  
> one is still running on the server. The timestamps are checked, and  
> if a running request detects that there was a change in the various  
> state/cache data it exits and yields to the new request.
>
> If you have configured an artificially short heartbeat interval in  
> your config, this may contribute to this, but now I'm just  
> speculating.
>
> Depending on how many devices you are supporting every few seconds  
> may or may not be "normal". You can bump the Horde log up to DEBUG -  
> where it will log all queries - and see exactly which INSERT/UPDATE  
> write operation is running every few seconds and we can go from there.

Debug log was a good idea.
Good news, Horde only trigger select queries and I see the disk write  
also with disable ActiveSync (not one active user in the webgui).

This must be a "problem" of my apache, as soon I start it the write  
starts as well.

Anyway, thank you for the ideas.

Samuel

>
>
> -- 
> mike
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