help for derby out of memory question.

[张伟华 <xj...@hotmail.com>]

 hi 
   my project use the derby 10.1 version .some table have 100000 records data ,when add ,delete ,query from the table frequently,the derby will out of memory ,why the memory can't release auto?  how can i free them by myself,help help thanks a lot.
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Re: help for derby out of memory question.

[Bryan Pendleton <bp...@amberpoint.com>]

>    my project use the derby 10.1 version .some table have 100000 records 
> data ,when add ,delete ,query from the table frequently,the derby will 
> out of memory ,why the memory can't release auto?  

Two suggestions:

1) Upgrade to 10.2.2.0 as soon as you can. It's got
   many fixes, including a number of memory-related fixes.

2) Ensure that you are closing all JDBC objects that
   you allocate. Verify that every ResultSet, every
   Statement, and every Connection that you use is
   closed when you are done using it. Closing these
   objects allows Derby to reclaim the memory resources.

thanks,

bryan

Re: help for derby out of memory question.

[Stanley Bradbury <St...@gmail.com>]

张伟华 wrote:
> hi
> my project use the derby 10.1 version .some table have 100000 records
> data ,when add ,delete ,query from the table frequently,the derby will
> out of memory ,why the memory can't release auto? how can i free them
> by myself,help help thanks a lot.
>
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Definitely check for the problems Bryan points out. The amount of memory
the Derby engine requires from the JVM will stabilize when all the
caches have been filled. The exact amount of memory required depends on
the database schema. I have seen systems where the default JVM size is
not sufficient to support the default Derby PageCache, resulting in
OutOfMemory exceptions. If the problem continues after verifying that
all objects are being closed then you can setup tests using a larger JVM
maxHeap or a smaller Derby PageCache until the two are balanced and you
no longer experience OutOfMemory exceptions.