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Elliott Clark commented on HBASE-15648: --------------------------------------- This one probably needs to be un-scheduled. It's a good idea. Using a lock to make sure that there aren't too many outstanding meta requests. However since the keys used are user specified the current implementation doesn't work. > Reduce number of concurrent region location lookups when MetaCache entry is > cleared > ----------------------------------------------------------------------------------- > > Key: HBASE-15648 > URL: https://issues.apache.org/jira/browse/HBASE-15648 > Project: HBase > Issue Type: Sub-task > Components: Client > Affects Versions: 1.3.0 > Reporter: Mikhail Antonov > Assignee: Mikhail Antonov > Attachments: HBASE-15648-branch-1.3.v1.patch > > > It seems in HConnectionImplementation#locateRegionInMeta if region location > is removed from the cache, with large number of client threads we could have > many of them getting cache miss and doing meta scan, which looks unnecessary > - we could empty mechanism similar to what we have in IdLock in HFileReader > to fetch the block to cache, do ensure that if one thread is already looking > up location for region R1, other threads who need it's location wait until > first thread finishes his work. -- This message was sent by Atlassian JIRA (v6.3.4#6332)