Hi All, During performance testing Amdatu Cassandra 0.2.1, I encountered the following issue: http://jira.amdatu.org/jira/browse/AMDATUCASSANDRA-114
The issue manifests itself by this WARNING message reoccurring in the log: WARNING: MemoryMeter uninitialized (jamm not specified as java agent); assuming liveRatio of 10.0. Usually this means cassandra-env.sh disabled jamm because you are using a buggy JRE; upgrade to the Sun JRE instead [org.amdatu.core.loghandler] After investigation (see issue) it appears that in Apache Cassandra 0.8 a new approach was introduced to determine when the memtable is flushed to an SSTable. This approach uses a MemoryMeter, initialized as Java agent. When you run Cassandra as standalone tool you are supposed to specify that Java agent upon JVM startup as java option (-javaagent:lib/jamm-0.2.2.jar). This obviously fails in an OSGi context. On the short term we can prevent the problem by switching back to the old 'when to flush the memtable' approach, used in 0.7. However, this new approach is the default and will probably the only supported approach in the future. So we need to think how we can initialize Java agents from OSGi. Does anyone have any experience with this? I tried the 'starting agents after JVM startup' approach described on http://download.oracle.com/javase/6/docs/api/java/lang/instrument/package-summary.html , but the OSGi classloader simply does not invoke my static agentmain (I modified the jamm jar to test that). Regards, Ivo GX Software | Ivo Ladage-van Doorn | Product Architect | Wijchenseweg 111 | 6538 SW Nijmegen | The Netherlands | T +31(0)24 - 388 82 61 | F +31(0)24 - 388 86 21 | [email protected]<mailto:[email protected]> | www.gxsoftware.com<http://www.gxsoftware.com> | twitter.com/GXSoftware<http://twitter.com/GXSoftware>
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