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https://issues.apache.org/jira/browse/IGNITE-7501?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Roman Kondakov updated IGNITE-7501:
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Description: When we call {{javax.cache.Cache#iterator()}} we get
{{java.util.Iterator}} which doesn't have a {{close()}} method. But underlying
{{GridCloseableIterator}} does have this method and it should be called when
all the work with the current iterator is done. Currently calling {{close()}}
for the underlying closeable iterator is delegated to
{{WeakQueryCloseableIterator}}. So, {{close()}} method is usually called in
GridCacheGateway#onEnter or on a garbage collection phase, which is not
acceptable in some situations. For example if MVCC is enabled, this *late*
iterator closing could dramatically increase the active queries tracking list
size which could lead to the performance and garbage collection ("vacuum")
issues. (was: When we call {{javax.cache.Cache#iterator()}} we get
{{java.util.Iterator}} which doesn't have a {{close()}} method. But underlying
{{GridCloseableIterator}} does have this method and it should be called when
all the work with the current iterator is done. Currently calling {{close()}}
for the underlying closeable iterator is delegated to
{{WeakQueryCloseableIterator}}. So, {{close()}} method is usually called on a
garbage collection phase, which is not acceptable in some situations. For
example if MVCC is enabled this *late* iterator closing could dramatically
increase the active queries tracking list size which could lead to the
performance and garbage collection ("vacuum") issues.)
> Improve underlying iterators closing process for cache iterators.
> -----------------------------------------------------------------
>
> Key: IGNITE-7501
> URL: https://issues.apache.org/jira/browse/IGNITE-7501
> Project: Ignite
> Issue Type: Improvement
> Components: cache
> Affects Versions: 2.3
> Reporter: Roman Kondakov
> Priority: Major
> Labels: cache, iterators, mvcc
> Fix For: 2.5
>
>
> When we call {{javax.cache.Cache#iterator()}} we get {{java.util.Iterator}}
> which doesn't have a {{close()}} method. But underlying
> {{GridCloseableIterator}} does have this method and it should be called when
> all the work with the current iterator is done. Currently calling {{close()}}
> for the underlying closeable iterator is delegated to
> {{WeakQueryCloseableIterator}}. So, {{close()}} method is usually called in
> GridCacheGateway#onEnter or on a garbage collection phase, which is not
> acceptable in some situations. For example if MVCC is enabled, this *late*
> iterator closing could dramatically increase the active queries tracking list
> size which could lead to the performance and garbage collection ("vacuum")
> issues.
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