Geoffrey Jacoby created PHOENIX-4021:
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Summary: 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
Fix For: 4.12.0
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.
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