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https://issues.apache.org/jira/browse/CALCITE-6753?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17908544#comment-17908544
]
Mihai Budiu commented on CALCITE-6753:
--------------------------------------
Here is an example of an unsound optimization:
Before:
{code:java}
public Object current() {
return Integer.valueOf((Integer) new
org.apache.calcite.linq4j.function.Function0() {
public Object apply() {
try {
return org.apache.calcite.runtime.SqlFunctions.toInt("a");
} catch (Exception e) {
return null;
}
}
}
.apply() * 12);
}
{code}
After:
{code:java}
public Object current() {
return Integer.valueOf((Integer) new
org.apache.calcite.linq4j.function.Function0() {
public Object apply() {
try {
return
$L4J$C$org_apache_calcite_runtime_SqlFunctions_toInt_a_;
} catch (Exception e) {
return null;
}
}
}
.apply() * 12);
}
static final int
$L4J$C$org_apache_calcite_runtime_SqlFunctions_toInt_a_ =
org.apache.calcite.runtime.SqlFunctions.toInt("a");
{code}
> DeterministicCodeOptimizer may lift method calls out of try-catch blocks
> ------------------------------------------------------------------------
>
> Key: CALCITE-6753
> URL: https://issues.apache.org/jira/browse/CALCITE-6753
> Project: Calcite
> Issue Type: Bug
> Components: core
> Affects Versions: 1.38.0
> Reporter: Mihai Budiu
> Priority: Minor
>
> The DeterministicCodeOptimizer tries to optimize the generated Java code.
> One of the things it does is to lift constant expressions into static
> variables.
> However, it does this regardless if a method call is within a try-catch block.
> For example, it may convert a safe cast into an unsafe cast.
> Unfortunately there is no easy way to check the context of the shuttle while
> optimizing an expression (i.e., whether an expression is within a try-catch
> block), since the accept calls of Expression objects are not
> doubly-dispatched.
> The only tool that is currently available to inhibit this optimization is to
> mark a function as non-deterministic.
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