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Kang Yuan commented on PHOENIX-4021: ------------------------------------ we backport this patch to phoenix4.11-HBase-0.98 .The performance go down a lot when CachineHTableFactory is disabled, so many HTables were been created and used once.It's wast and lower the performance can we make CachingHTableFactory thread safe instead of removing it > Remove CachingHTableFactory > --------------------------- > > Key: PHOENIX-4021 > URL: https://issues.apache.org/jira/browse/PHOENIX-4021 > Project: Phoenix > Issue Type: Bug > Affects Versions: 4.11.0 > Reporter: Geoffrey Jacoby > Assignee: Geoffrey Jacoby > Labels: globalMutableSecondaryIndex > Fix For: 4.12.0 > > Attachments: PHOENIX-4021.patch > > > CachingHTableFactory is used as a performance optimization when writing to > global indexes so that HTable instances are cached and later automatically > cleaned up, rather than instantiated each time we write to an index. > This should be removed for two reasons: > 1. It opens us up to race conditions, because HTables aren't threadsafe, but > CachingHTableFactory doesn't guard against two threads both grabbing the same > HTable and using it simultaneously. Since all ops going through a region > share the same IndexWriter and ParallelWriterIndexCommitter, and hence the > same CachingHTableFactory, that means separate operations can both be holding > the same HTable. > 2. According to discussion on PHOENIX-3159, and offline discussions I've had > with [~apurtell], HBase 1.x and above make creating throwaway HTable > instances cheap so the caching is no longer needed. > For 4.x-HBase-1.x and master, we should remove CachingHTableFactory, and for > 4.x-HBase-0.98, we should either get rid of it (if it's not too much of a > perf hit) or at least make it threadsafe. -- This message was sent by Atlassian JIRA (v6.4.14#64029)