"OutOfMemoryError: Java heap space" after building the history entry

Hi

For some days now, we are facing TC server (4.5.4) dying recurrently with the following logs:

[2009-10-06 00:40:41,169]   INFO - de.impl.history.DBBuildHistory - Start creating history entry for DSP Quality Assurance - Main Trunc :: Tests - FAT - SQL Server 2005 14661, date: 1254782615000 
[2009-10-06 00:40:41,169]   INFO - de.impl.history.DBBuildHistory - End creating history entry for DSP Quality Assurance - Main Trunc :: Tests - FAT - SQL Server 2005 14661 
[2009-10-06 00:40:42,231]   INFO - tbrains.buildServer.ACTIVITIES - Finished 14661 
[2009-10-06 00:40:47,231]  ERROR -   jetbrains.buildServer.SERVER - Java heap space
 
java.lang.OutOfMemoryError: Java heap space
[2009-10-06 00:40:47,231]  ERROR -   jetbrains.buildServer.SERVER - Error in JSP, request dump:
Path: /runtimeError.jsp
Method: POST
Param: projectId = [project8]
Param: refreshProject = [1]
 
java.lang.OutOfMemoryError: Java heap space
[2009-10-06 00:40:49,325]  ERROR - verSide.impl.BuildServerRunner - java.lang.OutOfMemoryError: Java heap space 
java.lang.OutOfMemoryError: Java heap space
[2009-10-06 00:40:49,325]   WARN -   jetbrains.buildServer.SERVER - Exception occurred in notificator 
java.lang.OutOfMemoryError: Java heap space
[2009-10-06 00:40:49,794]   WARN -   jetbrains.buildServer.SERVER - Exception occurred while communicating by XML RPC: java.lang.OutOfMemoryError: Java heap space /remote: 10.131.44.24:3247 
[2009-10-06 00:40:50,669]  ERROR -   jetbrains.buildServer.SERVER - Error in JSP, request dump:
Path: /runtimeError.jsp
Method: POST
Param: projectId = [project8]

What can we do to cope the problem?
We already have increased the -Xmx parameter but it doesn't really help.
Can we activate some specific traces to see what is really causing the OOME?