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From "James Taylor (JIRA)" <j...@apache.org>
Subject [jira] [Comment Edited] (PHOENIX-1267) Set scan.setSmall(true) when appropriate
Date Wed, 14 Jun 2017 23:40:00 GMT

    [ https://issues.apache.org/jira/browse/PHOENIX-1267?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16049813#comment-16049813
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James Taylor edited comment on PHOENIX-1267 at 6/14/17 11:39 PM:
-----------------------------------------------------------------

FYI, both PHOENIX-3073 and PHOENIX-3906 have useful information on this one.

I think a good first step would be to automatically make point lookup queries small scans
when the number of rows returned is less than a configurable threshold (see attached WIP patch).
Certainly if we're returning a single row, a small scan will be much better (according to
above JIRAs, 50% better). We could start with a configuration of 100 perhaps? Also, the configuration
parameter could be set to zero which would essentially disable this feature which is a good
thing.

Would be good to do a perf run to experiment with where the threshold would be for small scans
wrt how many rows will be returned for a point lookup.

[~Misraji] - this would be a good one for you to start with IMHO.





was (Author: jamestaylor):
FYI, both PHOENIX-3073 and PHOENIX-3906 have useful information on this one.

I think a good first step would be to automatically make point lookup queries small scans
when the number of rows returned is less than a configurable threshold (see attached WIP patch).
Certainly if we're returning a single row, a small scan will be much better (according to
above JIRAs, 50% better). We could start with a configuration of 100 perhaps? Also, the configuration
parameter could be set to zero which would essentially disable this feature which is a good
thing.

[~Misraji] - this would be a good one for you to start with IMHO.




> Set scan.setSmall(true) when appropriate
> ----------------------------------------
>
>                 Key: PHOENIX-1267
>                 URL: https://issues.apache.org/jira/browse/PHOENIX-1267
>             Project: Phoenix
>          Issue Type: Bug
>            Reporter: James Taylor
>              Labels: SFDC
>             Fix For: 4.12.0
>
>         Attachments: smallscan2.patch, smallscan3.patch, smallscan.patch
>
>
> There's a nice optimization that has been in HBase for a while now to set a scan as "small".
This prevents extra RPC calls, I believe. We should add a hint for queries that forces it
to be set/not set, and make our best guess on when it should default to true.



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