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https://issues.apache.org/jira/browse/CASSANDRA-1969?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13001868#comment-13001868
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Chris Goffinet commented on CASSANDRA-1969:
-------------------------------------------
Maybe I am missing something...
// A user-settable upper limit on the maximum amount of allocatable direct
// buffer memory. This value may be changed during VM initialization if
// "java" is launched with "-XX:MaxDirectMemorySize=<size>".
//
// The initial value of this field is arbitrary; during JRE initialization
// it will be reset to the value specified on the command line, if any,
// otherwise to Runtime.getRuntime.maxDirectMemory().
//
private static long directMemory = 64 * 1024 * 1024;
// If this method is invoked during VM initialization, it initializes the
// maximum amount of allocatable direct buffer memory (in bytes) from the
// system property sun.nio.MaxDirectMemorySize. The system property will
// be removed when it is accessed.
//
// If this method is invoked after the VM is booted, it returns the
// maximum amount of allocatable direct buffer memory.
public static long maxDirectMemory() {
if (booted)
return directMemory;
Properties p = System.getProperties();
String s = (String)p.remove("sun.nio.MaxDirectMemorySize");
System.setProperties(p);
if (s != null) {
if (s.equals("-1")) {
// -XX:MaxDirectMemorySize not given, take default
directMemory = Runtime.getRuntime().maxMemory();
} else {
long l = Long.parseLong(s);
if (l > -1)
directMemory = l;
}
}
return directMemory;
}
> Use BB for row cache - To Improve GC performance.
> -------------------------------------------------
>
> Key: CASSANDRA-1969
> URL: https://issues.apache.org/jira/browse/CASSANDRA-1969
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Environment: Linux and Mac
> Reporter: Vijay
> Assignee: Vijay
> Priority: Minor
> Attachments: 0001-Config-1969.txt,
> 0001-introduce-ICache-InstrumentingCache-IRowCacheProvider.txt,
> 0002-Update_existing-1965.txt, 0002-implement-SerializingCache.txt,
> 0002-implement-SerializingCacheV2.txt, 0003-New_Cache_Providers-1969.txt,
> 0003-add-ICache.isCopying-method.txt, 0004-Null-Check-and-duplicate-bb.txt,
> 0004-TestCase-1969.txt, 1969-rollup-and-config.txt, BB_Cache-1945.png,
> JMX-Cache-1945.png, Old_Cahce-1945.png, POC-0001-Config-1945.txt,
> POC-0002-Update_existing-1945.txt, POC-0003-New_Cache_Providers-1945.txt
>
>
> Java BB.allocateDirect() will allocate native memory out of the JVM and will
> help reducing the GC pressure in the JVM with a large Cache.
> From some of the basic tests it shows around 50% improvement than doing a
> normal Object cache.
> In addition this patch provide the users an option to choose
> BB.allocateDirect or store everything in the heap.
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