-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 Vidyadhar,
On 4/16/13 1:14 PM, Techienote com wrote: > With default setting we were getting frequent OOM errors. After > analyzing the heap dump we found > org.apache.poi.hssf.usermodel.HSSFSheet is accumulating more heap > memory. As per the application development this is the normal > behavior and have suggested to increase the maximum heap size to > 2048MB So, you keep lots of spreadsheets in memory for some reason? I can't imagine that loading a Microsoft Excel document into memory and keeping it in what POI calls "horrible spreadsheet format" is the best way to keep that information around. I suppose only /you/ know you requirements. Just how many spreadsheets do you need to keep in memory? > After increasing the max heap size we were seeing some large GC > pauses for the same we tried to change the JVM policy to CMS and > added following parameters > > -XX:+UseConcMarkSweepGC -XX:+UseParNewGC > -XX:+CMSParallelRemarkEnabled Did you enable verbose GC logging before/after you enabled those options? Did it help anything? Do you have any idea *why* your GCs were taking so long, or did you just Google for "java gc is taking a long time" and enable those options because they were "recommended" by someone? > Since then the long pauses reduced from 112 seconds to 90 seconds. Without seeing your data, I would guess that it's only a coincidence that your pauses have decreased in duration: you have likely not had any improvement by changing the GC configuration. > Also we have seeing regular permanent generation concurrent mark > failure which got reduced after changing NewSize to 512MB. Well, the NewSize shouldn't have any bearing on anything happening in PermGen, other than maybe allowing OutOfMemoryErrors to occur if you overfill PermGen. But that's not happening, here. > -Dsun.rmi.dgc.client.gcInterval=3600000 > -Dsun.rmi.dgc.server.gcInterval=3600000 -XX:+DisableExplicitGC If I understand correctly (and I don't claim to be a GC ergonomics expert), those options are mutually-exclusive. Disabling explicit GC should disable the RMI's use of .. explicit garbage-collection. So, if you really are using RMI, disabling explicit garbage-collection can ruin everything. [See http://www.oracle.com/technetwork/java/gc-tuning-5-138395.html#1.1.Other%20Considerations|outline]. Have you tried with a supported version of a Java VM? - -chris -----BEGIN PGP SIGNATURE----- Version: GnuPG/MacGPG2 v2.0.17 (Darwin) Comment: GPGTools - http://gpgtools.org Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQIcBAEBCAAGBQJRbalsAAoJEBzwKT+lPKRY1/kP/isK8UjCkC3PB1WCgSp9aDNI iOomoVHiXlL/0m4YTp/mxveB+8rs5edxrJPSeWJkpJAEs/4MU3MXVflapC2a90ij FhcXd0QvR1Cf0KE97wWiwXWRTtn60wOErutvOqZ9/HnaVwWRBZhczlJ+ZEwQ9ms1 vcFQMFsoOVFpFQT1rh4T+1ruRO+qorT1ybl7gkIPXNb4mkdgqrxkCiSwI2eB0w/p b2Ig1ugx9wNB9petyfhVpOffl7jbl/18KdJXj5N1hKQ2tAfzOCSf6nTNeFluG+zd J9/Wa6nOePgGf8+OzeIbvHS96u4SBOYt3NR1d/Vz1eIk1dvAxkp5aiBTvtv3l+Js /TogUoHSjXILfH+zzutvoucHCFcAOtDD4O658z/BcfROnRBpz6TYoEhtGob3d+Zp TFDM3N3WUt+566pKwNQtJfrOGJjq5IM7iBZKeofDiZGmJ1FiL89gdCWuHNpzvCX8 sV8xuwBVEWXQwz+VuLW2FB9PaTSOUBqOMBjbt3sjjuY7Uw6lMEszDhXP7nAhlYEj EsF9uXoWZBWMJZF+1p9KhjD3qNBhTKgB21TSzq59Mjw7FvhZE5pKDOqhYP/uyxi8 nigqrjKJbKATBztpOiR8bjvb+LSJy0hvf6bNhvAZY6S4qRU6K2kWkFfPz3v6QIiz GmxHvSCPXNHhx+X7S+3t =YmSW -----END PGP SIGNATURE----- --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
