Mujtaba Chohan created PHOENIX-1906:
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Summary: With large number of guideposts, queries that iterate
over a small range gets starved when running concurrently with larger queries
Key: PHOENIX-1906
URL: https://issues.apache.org/jira/browse/PHOENIX-1906
Project: Phoenix
Issue Type: Bug
Reporter: Mujtaba Chohan
Consider the scenario with a single region server. Table has 500 guide posts
(data is large enough that it won't fit either into HBase block or OS page
cache so it gets blocked on disk I/O during scans) and running the following 2
queries concurrently with and without stats enabled:
{code}select count(*) from table{code}
{code}select * from table limit 10{code}
With stats *disabled*, average time for these two queries is 100sec and 100ms
respectively. However with stats long running count aggregate query time drops
to 8 second but limit query time increases to 3 seconds. Degradation in limit
query time is even more evident when concurrency level is further increased.
[~jamestaylor]
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