CODEWITHSUNDEEP
javagarbage-collectionwildfly-9java-ee-8eclipse-mat
mcacorner
mcacorner

Reputation: 1274

Large number of duplicate string in memory/heapdump

I am using wildfly-9.0.1.Final on server.
Allocated memory is 20 GB with UseG1GC and UseStringDeduplication(with default threshold) flag.

I faced high memory usage on server, for troubleshooting I had collected heapdump. I used Eclipse MAT for heapdumnp analysis. The problem suspect suggest large nos. of String and StringBuilder object.Problem Suspect

When I run String: group by value. I saw large number of duplicate String.

String Value                                            |     Objects | Shallow Heap | Avg. Retained Size | Retained Heap
--------------------------------------------------------------------------------------------------------------------------
/D:/wildfly-9.0.1.Final/bin/content                     |   12,67,828 |  3,04,27,872 |                112 |  >= 135.42 MB
/D:/wildfly-9.0.1.Final/bin/content/myApp-ear.ear       |   12,67,828 |  3,04,27,872 |                144 |  >= 174.11 MB
/D:/wildfly-9.0.1.Final                                 |   12,67,827 |  3,04,27,848 |                 88 |  >= 106.40 MB
/D:/wildfly-9.0.1.Final/bin                             |   12,67,827 |  3,04,27,848 |                 96 |  >= 116.07 MB
/D:/wildfly-9.0.1.Final/bin/content/myApp-ear.ear/lib   |   12,64,464 |  3,03,47,136 |                152 |  >= 183.29 MB


I have check for some of the String and path to GC It look like this String is constructed by JVM/container.

path to GC

Is there any configuration to avoid these large nos. of String objects or I can troubleshoot this issue further.

Upvotes: 2

Views: 1152

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