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https://issues.apache.org/jira/browse/CALCITE-2717?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16704311#comment-16704311
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Haisheng Yuan edited comment on CALCITE-2717 at 11/30/18 6:19 AM:
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We have seen the OOM issue accidentally in our system because the cache is not
garbage-collected as expected. To avoid this issue, we can specify the cache's
maximum entry size, which I don't like. We can also change the cache loader to
return the clone of the key, like this:
{code:java}
CacheBuilder.newBuilder()
.softValues()
.build(CacheLoader.from(key -> key.clone()));
{code}
But we have to add clone() method into interface RelTrait.
[~julianhyde] thoughts?
was (Author: hyuan):
We have seen the OOM issue accidentally in our system because the cache is not
garbage-collected as expected. To avoid this issue, we can specify the cache's
maximum entry size, which I don't like. We can also change the cache loader to
return the clone of the key, like this:
{code:java}
CacheBuilder.newBuilder()
.softValues()
.build(CacheLoader.from(key -> key.clone()));
{code}
But we have to make RelTrait extend Cloneable interface.
[~julianhyde] thoughts?
> Cached traits in RelTraitDef's canonicalMap can't be garbage-collected
> -----------------------------------------------------------------------
>
> Key: CALCITE-2717
> URL: https://issues.apache.org/jira/browse/CALCITE-2717
> Project: Calcite
> Issue Type: Bug
> Components: core
> Reporter: Haisheng Yuan
> Assignee: Julian Hyde
> Priority: Major
>
> Softly-referenced objects will be garbage-collected in a globally
> least-recently-used manner, in response to memory demand. Even though
> canonicalMap's value is soft referenced, key is strong referenced, key and
> value are referencing the same object. So traits in the cache will never be
> garbage-collected, which may cause OOM if we have tons of different traits.
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