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https://issues.apache.org/jira/browse/PHOENIX-2724?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15380126#comment-15380126
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Samarth Jain commented on PHOENIX-2724:
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+1 to having a guard around guide post width. It is very easy to run into heap
space OOM errors if we have too many guideposts to collect in our
StatsCollector. FWIW, I ran into OOM on setting a guide post width of 50 bytes.
Let me see what I can do about pre-creating a big enough list/array by
calculating the estimated number of guide posts. The calculation should be
using the above guard too.
> 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: Lars Hofhansl
> Fix For: 4.8.0
>
> Attachments: 2724.txt, 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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