Hello Drill Dev Pros,
I have found the drill mongo store and would like to extend it to push
down INNER JOINs. Therefore I would like to rewrite INNER JOINs into the
mongo aggregation pipeline. Here is a SQL example:
SELECT *
FROM `mymongo.db`.`facts` `facts`
INNER JOIN `mymongo.db`.`set` `set` ON (`facts`.`group` = `set`.`group`)
WHERE ((`set`.`date` = '09.05.2017') AND (`set`.`id` = '1'))
Could you give me a hint how to do that? I am familiar with the
aggregation pipeline of mongo, but am not sure how to implement the
rewrite. I have found the push down of WHERE clauses for mongo [1]
But I am still struggling to do the same for inner joins. If I implement
"public class MongoPushDownInnerJoinScan extends
StoragePluginOptimizerRule" then how would the constructor look like.
Which equivalent of MongoGroupScan (AbstractGroupScan) [2] would I have
to implement? Any help would be very much appreciated.
Thank you and kind regards,
Dennis
[1]
https://github.com/apache/drill/blob/master/contrib/storage-mongo/src/main/java/org/apache/drill/exec/store/mongo/MongoPushDownFilterForScan.java
[2]
https://github.com/apache/drill/blob/master/contrib/storage-mongo/src/main/java/org/apache/drill/exec/store/mongo/MongoGroupScan.java
--
Dennis Knochenwefel
Founder
Reportix
Germany
