Re: Fwd: java.lang.OutOfMemoryError on closing resultset - Sean Erickson - com.mysql.lists.java

13 messages in com.mysql.lists.javaRe: Fwd: java.lang.OutOfMemoryError o...

From	Sent On	Attachments
Sean Erickson	21 Nov 2003 06:48
Christian Mack	21 Nov 2003 11:42
Morten Norby Larsen	21 Nov 2003 12:06
Kip Krueger	21 Nov 2003 12:17
Kip Krueger	21 Nov 2003 12:25
Jeff Mathis	21 Nov 2003 12:39
Sean Erickson	21 Nov 2003 13:46
Sean Erickson	21 Nov 2003 13:59
Jeff Mathis	21 Nov 2003 13:59
Mark Matthews	21 Nov 2003 14:12
Jeff Mathis	21 Nov 2003 14:37
Sean Erickson	21 Nov 2003 15:58
Mark Matthews	21 Nov 2003 17:34

Subject:	Re: Fwd: java.lang.OutOfMemoryError on closing resultset
From:	Sean Erickson (sean...@ia-inc.com)
Date:	11/21/2003 01:59:34 PM
List:	com.mysql.lists.java

Hmm, well, when I put a "stmt.close()" inside the loop, I get an OutOfMemory error there also.

I occurs to me that I must be doing something very wrong, although I cannot guess what it would be. The error is more so related to the size of the table that I am accessing than to the contrived example - as it happens even for the first time through the loop; in other words, the error occurs, IFF the table size > approx. 40-50 Megs.

thanks again for the responses,

-Sean

Jeff Mathis wrote:

java does automatic garbage collection. its one of the huge benefits -- you do not need to concern yourself with memory management. creating a new object in a loop more than likely is not the cause of the error. making sure to close the statement would be a better avenue to pursue.

Kip Krueger wrote:

Or can someone set me straight regarding "disposal of instantiated objects" - is that something that you even need to do in Java?

Begin forwarded message:

From: Kip Krueger <ki...@bigpikture.com>

Date: November 21, 2003 12:18:20 PM PST To: Christian Mack <mack...@gmx.de> Cc: Sean Erickson <sean...@ia-inc.com>, ja...@lists.mysql.com Subject: Re: java.lang.OutOfMemoryError on closing resultset

I'm no expert java programmer, but my C++ and Objective C experiences make me strongly agree with Christian on this one. Inside a loop instantiating a new object every iteration with no disposal? Seems a likely candidate for memory leakage. Try disposing of the "object" at the end of the loop each time and I bet the error goes away.

On Nov 21, 2003, at 11:42 AM, Christian Mack wrote:

Hi Sean

Why are you creating this DataObject in the while() loop?

object = new DataObject();

It will create a lot of objects never used.

Bye Christian

Sean Erickson wrote:

Hi all, ... # I then fill this table with 50,000 records # upon retrieving it, I get repeated "java.lang.OutOfMemory" errors at the position indicated below int setSize = 50000; int incSize = 10000; int position = 0; int rsSize = 100; stmt = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY); stmt.setMaxRows(rsSize); stmt.setFetchSize(Integer.MIN_VALUE); query = "SELECT ID, SUMMARY, PRIORITY, DESCRIPTION FROM " + table + " LIMIT " + position + "," + rsSize; rs = stmt.executeQuery( query); int count =1; while( rs.next() ) { object = new DataObject(); alert.id = rs.getLong(1); alert.summary = rs.getString(2); alert.priority = rs.getInt(3); description = rs.getString(4); count++; if(count == rsSize ) { System.out.println("id: " + alert.id); position += count; rs.close(); rs = null;

stmt.close(); // <--------- "OutOfMemory error"....

query = "SELECT ID, SUMMARY, PRIORITY, DESCRIPTION FROM " + table + " LIMIT " + position + "," + rsSize; System.out.println("query: " + query); try{ rs = stmt.executeQuery(query); // <------------ "OutOfMemory" Errors are thrown here } catch(java.lang.OutOfMemoryError t ) { System.out.println("OutOfMemoryError: " + t ); System.out.println("freeMemory: " + runtime.freeMemory() ); rs = stmt.executeQuery(query); // <------------ this call works } System.out.println("id: " + alert.id); System.gc() ; count =1; } } - some system specs: # java -version java version "1.4.1" Java(TM) 2 Runtime Environment, Standard Edition (build Blackdown-1.4.1-beta) Java HotSpot(TM) Client VM (build Blackdown-1.4.1-beta, mixed mode) # mysqladmin version mysqladmin Ver 8.23 Distrib 3.23.56, for redhat-linux-gnu on i386 Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB This software comes with ABSOLUTELY NO WARRANTY. This is free software, and you are welcome to modify and redistribute it under the GPL license Server version 3.23.56-log Protocol version 10 Connection Localhost via UNIX socket UNIX socket /var/lib/mysql/mysql.sock Uptime: 2 hours 29 min 0 sec Threads: 1 Questions: 795888 Slow queries: 5520 Opens: 132 Flush tables: 1 Open tables: 1 Queries per second avg: 89.026 erickson@gandalf:/home/mysql$ # uname -ar Linux gandalf 2.4.22-09032003a-smp #1 SMP Wed Sep 3 11:26:08 EDT 2003 i686 athlon i386 GNU/Linux #df -h /home/mysql Filesystem Size Used Avail Use% Mounted on /dev/hda5 28G 8.3G 19G 31% /home