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https://issues.apache.org/jira/browse/GEODE-9256?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17344839#comment-17344839
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ASF subversion and git services commented on GEODE-9256:
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Commit c407da1306990885052c411d3e679cafedda1e08 in geode's branch
refs/heads/develop from Dan Smith
[ https://gitbox.apache.org/repos/asf?p=geode.git;h=c407da1 ]
GEODE-9256: Use a stateless hscan implementation
Replacing our stateful hscan implementation with a stateless implementation
based on the same algorim as redis. This uses the stateless cursor method
add Object2ObjectOpenCustomHashMap in the previous commit.
> Remove hscan related fields from redis hash
> -------------------------------------------
>
> Key: GEODE-9256
> URL: https://issues.apache.org/jira/browse/GEODE-9256
> Project: Geode
> Issue Type: Improvement
> Components: redis
> Reporter: Dan Smith
> Assignee: Dan Smith
> Priority: Major
> Labels: pull-request-available
>
> To implement hscan it looks like we added a number of fields to every redis
> hash.
> {code}
> private ConcurrentHashMap<UUID, List<ByteArrayWrapper>> hScanSnapShots;
> private ConcurrentHashMap<UUID, Long> hScanSnapShotCreationTimes;
> private ScheduledExecutorService HSCANSnapshotExpirationExecutor = null;
> {code}
> This greatly increases the per hash overhead of radish. We also create
> HSCANSnapshotExpirationExecutor for every hash that has an active hscan,
> potentially using a lot of threads.
> These fields should be removed from the hash itself so we are not increasing
> its overhead. If we need to maintain state related to hscan it should
> probably be in some client specific data structure like the
> ExecutionHandlerContext.
> Redis itself looks like it doesn't maintain any server side state. We should
> use the same stateless cursor algorithm as redis and avoid keeping any state
> on the server. Here's an article that goes in depth on the redis algorithm
> https://www.freecodecamp.org/news/redis-hash-table-scan-explained-537cc8bb9f52/
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