[
https://issues.apache.org/jira/browse/CALCITE-3845?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Chunwei Lei updated CALCITE-3845:
---------------------------------
Description:
After ReduceExpressionsRule#reduceExpressionsInternal()[1],
{code:java}
CAST(CASE WHEN x then true WHEN y then TRUE ELSE false): boolean nullable
(exp1)
{code}
will be changed to
{code:java}
WHEN x then CAST(true): boolean nullable WHEN y then CAST(true): boolean
nullable ELSE CAST(false): boolean nullable. (exp2){code}
Then exp1 is considered as reduced. In the next step, by
ReduceExpressionsRule#simplifyPreservingType()[2], exp2 will be changed to
{code:java}
CAST(CASE WHEN x then true WHEN y then TRUE ELSE false): boolean nullable (exp3)
{code}
, which is exactly the same as exp1.
Though exp1 is actually not reduced, it is still considered as reduced[3],
which leads to CannotPlanException because of setImportance(project, 0.0)[4].
[1][https://github.com/apache/calcite/blob/master/core/src/main/java/org/apache/calcite/rel/rules/ReduceExpressionsRule.java#L618]
[2][https://github.com/apache/calcite/blob/master/core/src/main/java/org/apache/calcite/rel/rules/ReduceExpressionsRule.java#L624]
[3][https://github.com/apache/calcite/blob/master/core/src/main/java/org/apache/calcite/rel/rules/ReduceExpressionsRule.java#L303]
[4][https://github.com/apache/calcite/blob/master/core/src/main/java/org/apache/calcite/rel/rules/ReduceExpressionsRule.java#L312]
was:
After ReduceExpressionsRule#reduceExpressionsInternal()[1],
{code:java}
CAST(CASE WHEN x then true WHEN y then TRUE ELSE false): boolean nullable
(exp1)
{code}
will be changed to
{code:java}
WHEN x then CAST(true): boolean nullable WHEN y then CAST(true): boolean
nullable ELSE CAST(false): boolean nullable. (exp2){code}
Then exp1 is considered as reduced. In the next step, by
ReduceExpressionsRule#simplifyPreservingType()[2], exp2 will be changed to
{code:java}
CAST(CASE WHEN x then true WHEN y then TRUE ELSE false): boolean nullable (exp3)
{code}
, which is exactly the same as exp1.
Though exp1 is actually not reduced, it is still considered as reduced[3],
which leads to CannotPlanException because of setImportance(project, 0.0)[4].
[1][https://github.com/apache/calcite/blob/master/core/src/main/java/org/apache/calcite/rel/rules/ReduceExpressionsRule.java#L618]
[2][https://github.com/apache/calcite/blob/master/core/src/main/java/org/apache/calcite/rel/rules/ReduceExpressionsRule.java#L624]
[3][https://github.com/apache/calcite/blob/master/core/src/main/java/org/apache/calcite/rel/rules/ReduceExpressionsRule.java#L303]
[4][https://github.com/apache/calcite/blob/master/core/src/main/java/org/apache/calcite/rel/rules/ReduceExpressionsRule.java#L312]
> CASE WHEN expression with nullability CAST is considered as reduced wrongly
> in ReduceExpressionsRule
> ----------------------------------------------------------------------------------------------------
>
> Key: CALCITE-3845
> URL: https://issues.apache.org/jira/browse/CALCITE-3845
> Project: Calcite
> Issue Type: Bug
> Components: core
> Reporter: Chunwei Lei
> Assignee: Chunwei Lei
> Priority: Major
>
> After ReduceExpressionsRule#reduceExpressionsInternal()[1],
> {code:java}
> CAST(CASE WHEN x then true WHEN y then TRUE ELSE false): boolean nullable
> (exp1)
> {code}
> will be changed to
> {code:java}
> WHEN x then CAST(true): boolean nullable WHEN y then CAST(true): boolean
> nullable ELSE CAST(false): boolean nullable. (exp2){code}
> Then exp1 is considered as reduced. In the next step, by
> ReduceExpressionsRule#simplifyPreservingType()[2], exp2 will be changed to
> {code:java}
> CAST(CASE WHEN x then true WHEN y then TRUE ELSE false): boolean nullable
> (exp3)
> {code}
> , which is exactly the same as exp1.
> Though exp1 is actually not reduced, it is still considered as reduced[3],
> which leads to CannotPlanException because of setImportance(project, 0.0)[4].
>
> [1][https://github.com/apache/calcite/blob/master/core/src/main/java/org/apache/calcite/rel/rules/ReduceExpressionsRule.java#L618]
> [2][https://github.com/apache/calcite/blob/master/core/src/main/java/org/apache/calcite/rel/rules/ReduceExpressionsRule.java#L624]
>
> [3][https://github.com/apache/calcite/blob/master/core/src/main/java/org/apache/calcite/rel/rules/ReduceExpressionsRule.java#L303]
>
> [4][https://github.com/apache/calcite/blob/master/core/src/main/java/org/apache/calcite/rel/rules/ReduceExpressionsRule.java#L312]
>
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