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Posted to issues@drill.apache.org by "daniel (JIRA)" <ji...@apache.org> on 2015/12/03 15:43:11 UTC
[jira] [Created] (DRILL-4157) Add LIMIT push down rule for
relational database sources
daniel created DRILL-4157:
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Summary: Add LIMIT push down rule for relational database sources
Key: DRILL-4157
URL: https://issues.apache.org/jira/browse/DRILL-4157
Project: Apache Drill
Issue Type: New Feature
Components: Storage - Other
Reporter: daniel
Hi,
It will be very useful if queries with LIMIT or OFFSET clauses could be translated to native SQL when using relational databases as input.
Supose that I have a mysql connection configured. Right now, if I execute:
select * from mysql.schema.table LIMIT 1
This will be translated into:
select * from schema.table
And executed in the relational database server. As you can see, all the rows will be retrieved from the table. Then, apache drill will filter the result and show only one row.
The problem is that this is a huge performance penalty that can be avoided translating the query having this into account.
I'm not quite sure if this is a mysql problem or all the relational database sources share the same limitation. So, excuse me if I open this issue as a feature request.
Regards
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