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From Stefan Bühlmann <stefan.buehlm...@bfh.ch>
Subject Re: Performance Optimization for In-Memory ReadOnly Database
Date Wed, 25 May 2011 09:46:19 GMT
Hi Kristian,

thank you for your e-mail.  The insertion of the data takes a long time
(60s - 5min). I'm using JDBCTemplates with a SingleConnectionDataSource.
There is no need for multiple connections. I have created three indexed
which make the querying very efficient. However creating those indexes
requires just as much time as it takes to import all the CSV data
without indexes.

-- Stefan

On 24.05.2011 09:48, Kristian Waagan wrote:
> On 23.05.11 21:42, Stefan Bühlmann wrote:
>> Hi together,
>>
>> I'm using derby for a dataprocessing application.
>> SYSCS_UTIL.SYSCS_IMPORT_TABLE is used to import CSV data (around 100mb).
>> The tables contain huge amount of rows (~100k) with some CLOB (max 60mb)
>> columns.
>>
>> The table data is never altered (after the CSV import).
>>
>> Currently I'm using a in-memory database with pageCacheSize of 2000.
>>
>> Are there any other tricks to make querying the data more efficient?
> Hi Stefan,
>
> Do I understand you correctly if I say that you find the insert 
> performance acceptable, but you find querying the inserted data too slow?
>
> If so, is the data accessed by a single connection, or with multiple 
> connections concurrently?
> (i.e. can you run with a lower isolation level or use table locking?)
> Have you created the relevant indexes?
> Are you running a small set of queries repeatedly (using prepared 
> statements), or performing "ad-hoc" queries?
>
> It may be good to post some of the DDL and the queries which perform poorly.
>
>
> Regards,


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