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https://issues.apache.org/jira/browse/PHOENIX-2724?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15287314#comment-15287314
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Mujtaba Chohan commented on PHOENIX-2724:
-----------------------------------------
[~samarthjain] With [4.x-HBase-0.98
head|https://git-wip-us.apache.org/repos/asf?p=phoenix.git;a=commit;h=4837f1ff9d5a6265a07eecfc9d5d3ee55a56653f],
{{select * from T limit 10;}} and just the explain plan still takes ~20secs.
Explain: {code}
CLIENT 700422-CHUNK 1904445162 ROWS 3500865224783 BYTES SERIAL 1-WAY ROUND
ROBIN FULL SCAN OVER DATA_TABLE1B
SERVER 10 ROW LIMIT
CLIENT 10 ROW LIMIT
{code}
> Query with large number of guideposts is slower compared to no stats
> --------------------------------------------------------------------
>
> Key: PHOENIX-2724
> URL: https://issues.apache.org/jira/browse/PHOENIX-2724
> Project: Phoenix
> Issue Type: Bug
> Affects Versions: 4.7.0
> Environment: Phoenix 4.7.0-RC4, HBase-0.98.17 on a 8 node cluster
> Reporter: Mujtaba Chohan
> Assignee: Samarth Jain
> Fix For: 4.8.0
>
> Attachments: PHOENIX-2724.patch, PHOENIX-2724_addendum.patch,
> PHOENIX-2724_v2.patch
>
>
> With 1MB guidepost width for ~900GB/500M rows table. Queries with short scan
> range gets significantly slower.
> Without stats:
> {code}
> select * from T limit 10; // query execution time <100 msec
> {code}
> With stats:
> {code}
> select * from T limit 10; // query execution time >20 seconds
> Explain plan: CLIENT 876085-CHUNK 476569382 ROWS 876060986727 BYTES SERIAL
> 1-WAY FULL SCAN OVER T SERVER 10 ROW LIMIT CLIENT 10 ROW LIMIT
> {code}
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