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From "Peter Ondruška" <peter.ondru...@gmail.com>
Subject Re: performance issue
Date Thu, 16 Oct 2008 18:02:08 GMT
Windows on desktop by default will cache writes to disk whereas your
Linux may not. Also you may be running Windows JVM client hotspot and
Linux could be server hotspot.

On 10/16/08, Jonas Ahlinder <jonas.ahlinder@digitalroute.com> wrote:
> Hi.
>
> On Windows i use 1.6.0_10 and on Linux 1.6.0_10rc2 ( the final version was
> released today i think, havent gotten to install that yet ).
> As for parameters i only use -Xmx512m since the database is pretty bit.
> And i just realised there are some more details i should have mentioned
> about the database.
>
> The table is 500.000 rows which are created _before_ the actual work begins,
> these are empty rows that we do updates on to delete/insert/update
> information in the rows.
> This was to be able to stop the database growth, something that obviously
> didnt work.
>
> ________________________________________
> From: Peter Ondruška [peter.ondruska@gmail.com]
> Sent: Thursday, October 16, 2008 4:23 PM
> To: Derby Discussion
> Subject: Re: performance issue
>
> Hello, speed depends also on JVM. What version and JVM parameters are you
> using?
>
> On 10/16/08, Jonas Ahlinder <jonas.ahlinder@digitalroute.com> wrote:
>> Hi.
>>
>> We are developing a function to store session information, for use in a HA
>> environment.
>> However we are not reaching the throughput we want.
>>
>> Since its for persistance, we need to do autocommit on all operations.
>> The Table has two indexes and a blob of data.
>> The first index is a char(20) and the second is a timestamp.
>>
>> I put transaction log and data on separate disks.
>>
>> The first issue is that on a desktop machine ( running vista ) with two
>> 7.2k
>> rpm sata disks I get over 900 tps, while on a server ( running RHEL 5 )
>> and
>> two 15k rpm sas disks, I get around 250 tps.
>> I realise this might not have anything to do with derby, but running
>> iozone
>> tells me that the server has _a lot_ faster IO.
>> Im of course very interested in performance tweaking ideas regarding a HP
>> smart array p400i aswell.
>> We need to get it to work properly in the server enviroment.
>>
>> The other issue, and perhaps more related to derby, is that the timestamp
>> index wont stop growing.
>> After 24 hours it had grownfrom around 100mb to over 1gb, and the
>> performance obviously dropped massively due to this.
>> I have tried running in-place compression on the table, which didn't get
>> me
>> any space back.
>> What tests do you need me to run to be able to say what might be wrong ?
>>
>> Regards
>>
>> /Jonas Ahlinder
>>
>
>

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