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From Matt Pouttu-Clarke <Matt.Pouttu-Cla...@icrossing.com>
Subject Re: new feature request of Derby
Date Thu, 01 Sep 2011 15:54:49 GMT
Yes, there is a configurable page cache.  It is a nice feature of Derby that
it does not hog all of the JVM memory by default: it is polite.  You have to
ask it to use more memory.  Also make sure to set –Xmx on the jvm so all the
data fits.  Here is an example:
        stmt.execute("CALL SYSCS_UTIL.SYSCS_SET_DATABASE_PROPERTY(" +
                               "'derby.storage.pageCacheSize'," +
                               "'131072')");

I believe you can also set in derby.properties as well.  If you want to
pre-load the cache, simply query all the rows in the table.

Cheers,
Matt

On 9/1/11 5:33 AM, "鲍少明" <iokerica@gmail.com> wrote:

> I mean if one table holds a lot of data, then it cannot be all in memory.
> the latest version of hsql of its memory mode allows only keep like 8M data in
> memory but others
>  be kept in disk. This feature looks very useful.
> 
> 2011/9/1 鲍少明 <iokerica@gmail.com>
>> Hi Guys,
>>  
>> Is there any feature in Derby in its memory mode like Cache table in hsql?
>> I find this feature very important to us , especially there is some table
>> which holds a lot of table,
>> not suitable to be a pure memory table. But I want to still keep the other
>> tables in memory mode.
>>  
>> Is that possible?
>>  
>> Thanks,
>> Clark
> 
> 


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