[
https://issues.apache.org/jira/browse/CALCITE-4392?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Liya Fan updated CALCITE-4392:
------------------------------
Description:
Method {{SqlTypeUtil#equalSansNullability(RelDataTypeFactory, RelDataType,
RelDataType) is on the hot path for many scenarios, as it compare types with
nullability ignored.
In the implementation, the expensive operations are
{{RelDataType#equals(Object)}} and
{{RelDataTypeFactory#createTypeWithNullability}}, especially for types with
multiple sub-fields.
For the current implementation, the {{RelDataType#equals(Object)}} is called at
least once, and {{RelDataTypeFactory#createTypeWithNullability}} is called
whenever the nullability values are different.
We can improve the implementation so that {{RelDataType#equals(Object)}} is
called exactly once, and the call to
{{RelDataTypeFactory#createTypeWithNullability}} can be avoided if the types
are totally different (with different type names, and nullability values)
{noformat}
if (type1.isNullable() == type2.isNullable()) {
return type1.equals(type2);
} else {
return type1.equals(
factory.createTypeWithNullability(type2, type1.isNullable()));
}
{noformat}
was:
Method {{SqlTypeUtil#equalSansNullability(RelDataTypeFactory, RelDataType,
RelDataType) is on the hot path for many scenarios, as it compare types with
nullability ignored.
In the implementation, the expensive operations are
{{RelDataType#equals(Object)}} and
{{RelDataTypeFactory#createTypeWithNullability}}, especially for types with
multiple sub-fields.
For the current implementation, the {{RelDataType#equals(Object)}} is called at
least once, and {{RelDataTypeFactory#createTypeWithNullability}} is called
whenever the nullability values are different.
We can improve the implementation so that {{RelDataType#equals(Object)}} is
called at most once, and the call to
{{RelDataTypeFactory#createTypeWithNullability}} can be avoided if the types
are totally different (with different type names, and nullability values)
{noformat}
if (type1.isNullable() == type2.isNullable()) {
return type1.equals(type2);
} else {
return type1.equals(
factory.createTypeWithNullability(type2, type1.isNullable()));
}
{noformat}
> The operation of checking types equal ignoring null can be more efficient
> -------------------------------------------------------------------------
>
> Key: CALCITE-4392
> URL: https://issues.apache.org/jira/browse/CALCITE-4392
> Project: Calcite
> Issue Type: Improvement
> Components: core
> Reporter: Liya Fan
> Assignee: Liya Fan
> Priority: Major
>
> Method {{SqlTypeUtil#equalSansNullability(RelDataTypeFactory, RelDataType,
> RelDataType) is on the hot path for many scenarios, as it compare types with
> nullability ignored.
> In the implementation, the expensive operations are
> {{RelDataType#equals(Object)}} and
> {{RelDataTypeFactory#createTypeWithNullability}}, especially for types with
> multiple sub-fields.
> For the current implementation, the {{RelDataType#equals(Object)}} is called
> at least once, and {{RelDataTypeFactory#createTypeWithNullability}} is called
> whenever the nullability values are different.
> We can improve the implementation so that {{RelDataType#equals(Object)}} is
> called exactly once, and the call to
> {{RelDataTypeFactory#createTypeWithNullability}} can be avoided if the types
> are totally different (with different type names, and nullability values)
> {noformat}
> if (type1.isNullable() == type2.isNullable()) {
> return type1.equals(type2);
> } else {
> return type1.equals(
> factory.createTypeWithNullability(type2, type1.isNullable()));
> }
> {noformat}
--
This message was sent by Atlassian Jira
(v8.3.4#803005)
