Ruben Q L created CALCITE-4419:
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Summary: Posix regex operators cannot be used within RelBuilder
Key: CALCITE-4419
URL: https://issues.apache.org/jira/browse/CALCITE-4419
Project: Calcite
Issue Type: Bug
Components: core
Reporter: Ruben Q L
Fix For: 1.27.0
Posix regex operators are special, they are defined as binary ({{public class
SqlPosixRegexOperator extends SqlBinaryOperator}}), but their actual
implementation takes three arguments, the third being a caseSensitive boolean
flag ({{SqlFunctions#posixRegex(String s, String regex, Boolean
caseSensitive)}}).
Using them in SQL works fine. The magic happens in
{{SqlPosixRegexOperator#createCall}}, which adds an extra boolean parameter
(the caseSensitive flag) into the call:
{code:java}
@Override public SqlCall createCall(SqlLiteral functionQualifier, SqlParserPos
pos, SqlNode... operands) {
pos = pos.plusAll(Arrays.asList(operands));
operands = Arrays.copyOf(operands, operands.length + 1);
operands[operands.length - 1] = SqlLiteral.createBoolean(caseSensitive,
SqlParserPos.ZERO);
return new SqlBasicCall(this, operands, pos, false, functionQualifier);
}
{code}
However, if we try to use them in a plan created by RelBuilder, problems occur.
1) The following plan:
{code:java}
RelBuilder builder = ...
builder
.scan("s", "emps")
.filter(
builder.call(
SqlStdOperatorTable.POSIX_REGEX_CASE_SENSITIVE,
builder.field("name"),
builder.literal("E...")))
...
{code}
Fails because it cannot find the implementor method
{noformat}
Caused by: java.lang.IllegalStateException: Unable to implement
EnumerableCalc(expr#0..4=[{inputs}], expr#5=['E...'], expr#6=[POSIX REGEX CASE
SENSITIVE($t2, $t5)]...
...
Caused by: java.lang.NoSuchMethodException:
org.apache.calcite.runtime.SqlFunctions.posixRegex(java.lang.String,
java.lang.String)
{noformat}
2) The solution seems add a (somehow redundant, but necessary due to posix
regex operators design) third boolean parameter:
{code:java}
.filter(
builder.call(
SqlStdOperatorTable.POSIX_REGEX_CASE_SENSITIVE,
builder.field("name"),
builder.literal("E..."),
builder.literal(true)))
{code}
But it fails validating the operands:
{noformat}
wrong operand count 3 for POSIX REGEX CASE SENSITIVE
java.lang.AssertionError: wrong operand count 3 for POSIX REGEX CASE SENSITIVE
at org.apache.calcite.util.Litmus$1.fail(Litmus.java:31)
at
org.apache.calcite.sql.SqlBinaryOperator.validRexOperands(SqlBinaryOperator.java:200)
{noformat}
3) So, it would seem {{SqlPosixRegexOperator}} should override
{{validRexOperands}} to support 2 *and 3* parameters (which in fact would seem
correct and aligned to the current overridden behavior of
{{SqlPosixRegexOperator#getOperandCountRange}} and
{{SqlPosixRegexOperator#checkOperandTypes}}:
{code:java}
@Override public boolean validRexOperands(int count, Litmus litmus) {
if (count != 2 && count != 3) {
return litmus.fail("wrong operand count {} for {}", count, this);
}
return litmus.succeed();
}
{code}
But now the test fails with almost the same message as the very first one:
{noformat}
Caused by: java.lang.IllegalStateException: Unable to implement
EnumerableCalc(expr#0..4=[{inputs}], expr#5=['E...'], expr#6=[true],
expr#7=[POSIX REGEX CASE SENSITIVE($t2, $t5, $t6)]...
...
Caused by: java.lang.NoSuchMethodException:
org.apache.calcite.runtime.SqlFunctions.posixRegex(java.lang.String,
java.lang.String, boolean)
{noformat}
4) The problem seems to be a mismatch between our third argument (boolean) and
the implementor's third argument (Boolean). Looking at the code, it seems clear
that a primitive boolean should / must be used since having a null Boolean
object makes no sense (and will case a NPE anyway). So if we change it:
{code:java}
// BuiltInMethod.java
...
POSIX_REGEX(SqlFunctions.class, "posixRegex", String.class, String.class,
Boolean.class), // instead of Boolean.class
// ---------
// SqlFunctions.java
...
public static boolean posixRegex(String s, String regex, boolean caseSensitive)
// instead of Boolean
{ ... }
{code}
Now our test finally succeeds.
Therefore, I propose to implement these sequence of changes in order to solve
this issue.
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