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https://issues.apache.org/jira/browse/GEODE-9801?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Anthony Baker updated GEODE-9801:
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Labels: (was: needsTriage)
> CachePerfStats.replicatedTombstonesSize and nonReplicatedTombstonesSize are
> not accurate
> ----------------------------------------------------------------------------------------
>
> Key: GEODE-9801
> URL: https://issues.apache.org/jira/browse/GEODE-9801
> Project: Geode
> Issue Type: Bug
> Components: core
> Affects Versions: 1.12.0
> Reporter: Darrel Schneider
> Priority: Major
>
> This issue has been around since Geode 1.0.
> CachePerfStats.replicatedTombstonesSize and nonReplicatedTombstonesSize are
> supposed to help geode users figure out how much memory is being used by
> tombstones. But because of some over sites in the sizing code they actual
> amount of memory used by tombstones is significantly higher. Some of the
> mistakes made:
> 1. A Tombstone is added to a ConcurrentLinkedQueue. This is accounted for as
> a single objRef. But each add to a ConcurrentLinkedQueue add a Node instance
> so you have the object header size plus two objRefs.
> 2. The size of the RegionEntry is not accounted for. The size of the key in
> this entry is but most of the memory used is in the RegionEntry fields
> itself. And the key, in some cases, is stored inline in primitive fields in
> the RegionEntry so Tombstone.getSize should not be asking the RegionEntry for
> its key and then sizing it but should instead just ask the RegionEntry for
> its memory footprint. It can then figure out if it needs to size any of the
> objects it references (like the key).
> 3. the Tombstone class it self accounts for all its fields but forgot about
> its own object header.
> To fix this have the Tombstone class add the following:
> {code:java}
> private static final TOMBSTONE_OVERHEAD =
> JvmSizeUtils.memoryOverhead(Tombstone.class);
> {code}
> For the Node overhead on ConcurrentLinkedQueue add this:
> {code:java}
> private static final NODE_OVERHEAD =
> JvmSizeUtils.roundUpSize(JvmSizeUtils.getObjectHeaderSize() +
> 2*JvmSizeUtils.getReferenceSize());
> {code}
> For RegionEntry add a new "memoryOverhead" method on HashRegionEntry and then
> implement it in all the many leaf classes. You can do this by modifying
> LeafRegionEntry.cpp and running generateRegionEntryClasses.sh. You will want
> each class to have a private static final field that calls
> JvmSizeUtils.memoryOverhead(<CLASSNAME>.class) and then decide at runtime if
> the instance references other objects that should be sized (like key, value,
> DiskId, etc.).
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