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Handle repeated predicate pushdown into Hive connector #984

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martint
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@martint martint commented Jun 13, 2019

The previous implementation was only considering the first
attempt where a filter is pushed down into the Hive connector.
As a result, for a query like this, the partition filter above
the bottommost filter would be ignored:

SELECT * FROM (
    SELECT * FROM t WHERE a in (1, 2)
) u
WHERE u.pk = 'b';

@cla-bot cla-bot bot added the cla-signed label Jun 13, 2019
@findepi
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findepi commented Jun 13, 2019

@martint make sure this change doesn't increase the number of times we query the Metastore for partitions.
Each call may be costly (in seconds or sometimes even worse).
You can easily track this with #946

Also, make sure that queries like

SELECT * FROM (
    SELECT * FROM t WHERE pk > 0
) u
WHERE u.pk = 'b';

do not hit the hive.max-partitions-per-scan limit.

Execute the rules after all the predicate pushdowns, decorrelations and
other simplifications have executed to avoid calling into the connectors
multiple times if possible (these actions can be expensive for some connectors
such as Hive).
NONE means no rows would be produced, which is incorrect.
The previous implementation was only considering the first
attempt where a filter is pushed down into the Hive connector.
As a result, for a query like this, the partition filter above
the bottommost filter would be ignored:

    SELECT * FROM (
        SELECT * FROM t WHERE a in (1, 2)
    ) u
    WHERE u.pk = 'b';
@electrum electrum closed this Jun 14, 2019
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Merged as 74b7a79

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4 participants