Keith Turner created ACCUMULO-2801:
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Summary: define tablet syncs walog for each tablet in a batch
Key: ACCUMULO-2801
URL: https://issues.apache.org/jira/browse/ACCUMULO-2801
Project: Accumulo
Issue Type: Bug
Affects Versions: 1.6.0, 1.5.1, 1.5.0
Reporter: Keith Turner
When the batch writer sends a batch of mutations for N tablets that were not
currently using a walog, then define tablet will be called for each tablet.
Define tablet will sync the walog. In hadoop 2 hsync is used, which is much
slower than hadoop1 sync calls. If hsync takes 50ms and there are 100 tablets,
then this operation would take 5 secs. The calls to define tablet do not occur
frequently, just when walogs switch or tablets are loaded so the cost will be
amortized. Ideally there could be one walog sync call for all of the tablets
in a batch of mutations.
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