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https://issues.apache.org/jira/browse/PHOENIX-2724?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15352489#comment-15352489
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James Taylor commented on PHOENIX-2724:
---------------------------------------

bq. Another pretty easy fix would be to not try to get the guideposts for 
certain queries - point lookups and serial queries. We're fine just using the 
region boundaries in those cases.
On second thought, probably just for serial queries (but I don't recall if we 
get the guideposts for these). FWIW, I don't think we need to. It's useful to 
get guideposts for point lookups so we maximize the parallelism.

> 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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