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Re: Query problem for hundreds of thousands of records

Subject: Re: Query problem for hundreds of thousands of records
From: WHIRLYCOTT
Date: Wed, 13 Oct 2004 00:03:06 -0400
I'm interested in the reasoning behind your suggestion...?
phil.

Joe Latty wrote:

Without going into why you would want a query to return 350k records,
you may have to change some parameters in the OJB.properties file.

Look for the following and you may need to change maxActive to a
non-positive number. This can give out of memory errors.

# maximum number of brokers that can be borrowed from the
# pool at one time. When non-positive, there is no limit.
maxActive=100

-----Original Message-----
From: WHIRLYCOTT [mailto:phil@xxxxxxxxxxxxxx] Sent: Wednesday, 13 October 2004 12:02 PM
To: OJB Users List
Subject: Re: Query problem for hundreds of thousands of records

If you need the entire resultset in memory, you probably need to provide

more memory to your jvm or add more memory physically to your hardware.

It sounds like, in effect, that you are basically making a copy of your database table with ~350k records in memory!

What happens when 2 users hit your website at the same time? What happens when 100 users hit your site?

I don't know the specifics of what you are doing, but it doesn't sound like a particularily good solution. Why do you think you need to have the entire result set in memory?

phil.

[ Muliawan Sjarif ] wrote:


If I need the entire resultset in the memory what would be the best
approach? It seems that broker.getCollectionByQuery(q) stuck with huge
records.


On Tue, 12 Oct 2004 16:09:11 -0400, WHIRLYCOTT <phil@xxxxxxxxxxxxxx>

wrote:

You probably are doing something like this:

     Collection c = broker.getCollectionByQuery(q);

... and ought to be doing something like this:

     Iterator i = broker.getIteratorByQuery(q);

Unless you need the entire result set in memory, this should be your
preferred approach.  Just iterate through the results and do what you
need to do to each of them.

phil.

[ Muliawan Sjarif ] wrote:



Hi,

I was doing a quick test for OJB particularly using PersistenceBroker
on one table that consists of 352544 records. No matter how many

times

I tried, in the end all I got was the browser not responding (no
result displayed on the page) and tomcat throwed

java.lang.OutOfMemory

exception. For this test, dynamic proxy was utilized.

Pertaining to this problem, I wonder if anyone has encountered

similar

problem. Or is there somewhere in the OJB's properties that need to

be

tweaked?

Many thanks.

Regards,
Muliawan

--
                                Whirlycott
                                Philip Jacob
                                phil@xxxxxxxxxxxxxx
                                http://www.whirlycott.com/phil/

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                                  Whirlycott
                                  Philip Jacob
                                  phil@xxxxxxxxxxxxxx
                                  http://www.whirlycott.com/phil/

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