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https://issues.apache.org/jira/browse/IGNITE-18931?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Pavel Pereslegin updated IGNITE-18931:
--------------------------------------
Description:
Currently expressions like "expr() = expr()" and "expr() != expr()" for
non-deterministic functions (for example rand_uuid()) do not work correctly.
The problem seems to be related to the optimization made in
RexProgramBuilder#registerInternal, ignoring the fact that the function might
be non-deterministic.
{code:java}
final RexSimplify simplify =
new RexSimplify(rexBuilder, RelOptPredicateList.EMPTY,
RexUtil.EXECUTOR);
expr = simplify.simplifyPreservingType(expr);
{code}
This optimization translates comparison
{{<>($t1, $t1)}}
to
{{CAST(AND(null, IS NULL($t1))):BOOLEAN NOT NULL}}
The first expression can be translated into two function calls, but the second
expression unambiguously makes only one call.
And it looks like a naive fix would be to apply this optimization only if
{{RexUtil.isDeterministic(rexNode)}} returns true.
{{RexProgramBuilder}} currently is not a part of Ignite-3 codebase and it seems
that it will be better to do such fix in Apache Calcite.
However, before doing this, we need to learn the discussions that have been
made on this topic previously.
CALCITE-2823
CALCITE-3760
CALCITE-2142
CALCITE-2638
CALCITE-3531
CALCITE-4256
was:
Currently expressions like "expr() = expr()" and "expr() != expr()" for
non-deterministic functions (for example rand_uuid()) do not work correctly.
The problem seems to be related to the optimization made in
RexProgramBuilder#registerInternal, ignoring the fact that the function is
non-deterministic.
{code:java}
final RexSimplify simplify =
new RexSimplify(rexBuilder, RelOptPredicateList.EMPTY,
RexUtil.EXECUTOR);
expr = simplify.simplifyPreservingType(expr);
{code}
This optimization translates comparison
{{<>($t1, $t1)}}
to
{{CAST(AND(null, IS NULL($t1))):BOOLEAN NOT NULL}}
The first expression can be translated into two function calls, but the second
expression unambiguously makes only one call.
And it looks like a naive fix would be to apply this optimization only if
{{RexUtil.isDeterministic(rexNode)}} returns true.
{{RexProgramBuilder}} currently is not a part of Ignite-3 codebase and it seems
that it will be better to do such fix in Apache Calcite.
However, before doing this, we need to learn the discussions that have been
made on this topic previously.
CALCITE-2823
CALCITE-3760
CALCITE-2142
CALCITE-2638
CALCITE-3531
CALCITE-4256
> Sql. Invalid expression code generation for comparing the results of a
> non-deterministic function.
> --------------------------------------------------------------------------------------------------
>
> Key: IGNITE-18931
> URL: https://issues.apache.org/jira/browse/IGNITE-18931
> Project: Ignite
> Issue Type: Improvement
> Components: sql
> Reporter: Pavel Pereslegin
> Priority: Major
> Labels: calcite2-required, calcite3-required, ignite-3
>
> Currently expressions like "expr() = expr()" and "expr() != expr()" for
> non-deterministic functions (for example rand_uuid()) do not work correctly.
> The problem seems to be related to the optimization made in
> RexProgramBuilder#registerInternal, ignoring the fact that the function might
> be non-deterministic.
> {code:java}
> final RexSimplify simplify =
> new RexSimplify(rexBuilder, RelOptPredicateList.EMPTY,
> RexUtil.EXECUTOR);
> expr = simplify.simplifyPreservingType(expr);
> {code}
> This optimization translates comparison
> {{<>($t1, $t1)}}
> to
> {{CAST(AND(null, IS NULL($t1))):BOOLEAN NOT NULL}}
> The first expression can be translated into two function calls, but the
> second expression unambiguously makes only one call.
> And it looks like a naive fix would be to apply this optimization only if
> {{RexUtil.isDeterministic(rexNode)}} returns true.
> {{RexProgramBuilder}} currently is not a part of Ignite-3 codebase and it
> seems that it will be better to do such fix in Apache Calcite.
> However, before doing this, we need to learn the discussions that have been
> made on this topic previously.
> CALCITE-2823
> CALCITE-3760
> CALCITE-2142
> CALCITE-2638
> CALCITE-3531
> CALCITE-4256
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