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https://issues.apache.org/jira/browse/HIVE-25074?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17342181#comment-17342181
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Kishen Das commented on HIVE-25074:
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[~pvary] I don't see any usage of this API in Impala.
> Remove Metastore flushCache usage
> ---------------------------------
>
> Key: HIVE-25074
> URL: https://issues.apache.org/jira/browse/HIVE-25074
> Project: Hive
> Issue Type: Improvement
> Components: Metastore, Standalone Metastore
> Affects Versions: 4.0.0
> Reporter: Miklos Szurap
> Assignee: Zoltan Chovan
> Priority: Major
> Labels: pull-request-available
> Time Spent: 10m
> Remaining Estimate: 0h
>
> The "flushCache" in HiveMetaStore with the ObjectStore implementation is
> currently a NOOP:
> {code:java}
> public void flushCache() {
> // NOP as there's no caching
> } {code}
> The HBaseStore (HBaseReadWrite) had some logic in it, however it has been
> removed in HIVE-17234.
> As I see the calls are going like this:
> HiveMetaStoreClient.flushCache() -> CachedStore.flushCache() ->
> ObjectStore.flushCache()
> There are significant amount of calls (about 10% of all calls) made from the
> client to the server - to do nothing. We could spare the call to the server
> completely, including getting a DB connection which can take 1+ seconds under
> high load scenarios slowing down Hive queries unnecessarily.
> Can we:
> # Deprecate the RawStore.flushCache (if there are other implementations)
> # Deprecate the HiveMetaStoreClient.flushCache()
> # Do the NOOP on the client side in HiveMetaStoreClient.flushCache() (while
> it is not removed in a next version)
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