[SPARK-15916][SQL] Correctly pushdown top level AND operators with parenthesis in JDBC data source #13640
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I remember this was written by you @viirya. Could you take a look please? |
HyukjinKwon
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Test build #60399 has finished for PR 13640 at commit
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cc @rxin do you mind if I ask to review this please? |
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I added this to my team's backlog. |
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Thanks! |
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LGTM |
| */ | ||
| private val filterWhereClause: String = | ||
| filters.flatMap(JDBCRDD.compileFilter).mkString(" AND ") | ||
| filters.flatMap(JDBCRDD.compileFilter).map(p => s"($p)").mkString(" AND ") |
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How about getWhereClause? There is also a AND at https://github.com/apache/spark/pull/13640/files#diff-5a29ce8f760092fb4a9c1f190cc2f61cR315
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## What changes were proposed in this pull request?
This PR fixes the problem that the precedence order is messed when pushing where-clause expression to JDBC layer.
**Case 1:**
For sql `select * from table where (a or b) and c`, the where-clause is wrongly converted to JDBC where-clause `a or (b and c)` after filter push down. The consequence is that JDBC may returns less or more rows than expected.
**Case 2:**
For sql `select * from table where always_false_condition`, the result table may not be empty if the JDBC RDD is partitioned using where-clause:
```
spark.read.jdbc(url, table, predicates = Array("partition 1 where clause", "partition 2 where clause"...)
```
## How was this patch tested?
Unit test.
This PR also close #13640
Author: hyukjinkwon <[email protected]>
Author: Sean Zhong <[email protected]>
Closes #13743 from clockfly/SPARK-15916.
(cherry picked from commit ebb9a3b)
Signed-off-by: Cheng Lian <[email protected]>
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What changes were proposed in this pull request?
This PR inserts the correct parenthesis between top level
ANDoperators.For example, the where clause below:
is being parsed as below:
This is fine for other sub filters for each element in
Array[Filter]but it is not considering the parenthesis and precedence withANDbetween elements inArray[Filter].This PR produces the correct condition as below:
How was this patch tested?
Unit test in
JDBCSuite.