Yunhong Zheng created CALCITE-5907:
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Summary: Unexpected boolean expression simplification for And
expression
Key: CALCITE-5907
URL: https://issues.apache.org/jira/browse/CALCITE-5907
Project: Calcite
Issue Type: Bug
Components: core
Affects Versions: 1.35.0
Reporter: Yunhong Zheng
Fix For: 1.36.0
As [FLINK-27402|https://issues.apache.org/jira/browse/FLINK-27402] shown. If
we have a table MyTable(a Int, b Boolean, c String). Calcite will not
simplify this case ( c is Varchar type while SqlLiteral is boolean):
{code:java}
SELECT * FROM MyTable WHERE c = true;{code}
As the logical plan is :
{code:java}
LogicalSink(table=[*anonymous_collect$1*], fields=[a, b, c])
+- LogicalProject(inputs=[0..2])
+- LogicalFilter(condition=[=($2, true)])
+- LogicalTableScan(table=[[default_catalog, default_database,
MyTable]]){code}
However, Calcite will simplify this case while simplifyAnd :
{code:java}
SELECT * FROM MyTable WHERE b = true and c = true;{code}
As the logical plan is shown below: 'b = true' and 'c = true' both were
simplified to 'b' and 'c':
{code:java}
LogicalSink(table=[*anonymous_collect$1*], fields=[a, b, c])
+- LogicalProject(inputs=[0..2])
+- LogicalFilter(condition=[AND($1, $2)])
+- LogicalTableScan(table=[[default_catalog, default_database,
MyTable]]){code}
This may cause error because of filter condition is a Varchar type literal.
After reading Calcite's code, I found that. The logic of RexSimplify.implify()
and RexSimplify.implifyAnd() is different, where the logic of
RexSimplify.implifyAnd() is problematic:
{code:java}
// Simplify BOOLEAN expressions if possible
while (term.getKind() == SqlKind.EQUALS) {
RexCall call = (RexCall) term;
if (call.getOperands().get(0).isAlwaysTrue()) {
term = call.getOperands().get(1);
terms.set(i, term);
continue;
} else if (call.getOperands().get(1).isAlwaysTrue()) {
term = call.getOperands().get(0);
terms.set(i, term);
continue;
}
break;
} {code}
The above code cannot make such a simple judgment, as there may not be an
implicit conversion to ensure that the types on both sides of the condition are
consistent.
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