GitHub user jiangxb1987 opened a pull request:
https://github.com/apache/spark/pull/15319
[SPARK-17733][SQL] InferFiltersFromConstraints rule never terminates for
query
## What changes were proposed in this pull request?
The function `QueryPlan.inferAdditionalConstraints` and
`UnaryNode.getAliasedConstraints` can produce a non-converging set of
constraints for recursive functions. For instance, if we have two constraints
of the form(where a is an alias):
`a = b, a = f(b, c)`
Applying both these rules in the next iteration would infer:
`f(b, c) = f(f(b, c), c)`
This process repeated, the iteration won't converge and the set of
constraints will grow larger and larger until OOM.
To fix this problem, we collect alias from expressions and skip infer
constraints if we are to transform an `Expression` to another which contains it.
## How was this patch tested?
Add new testcase in `SQLQuerySuite`.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/jiangxb1987/spark constraints
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/spark/pull/15319.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #15319
----
commit b77a4d638d29d8d9c939a653d6e79e8edc5203fd
Author: jiangxingbo <[email protected]>
Date: 2016-10-01T04:33:30Z
modify function inferAdditionalConstraints to avoid producing
non-converging set of constraints
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