[CALCITE-4073] Add a new component RexNormalize for more effect rex nodes normalization

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.24.0
• Fix Version/s: 1.24.0
• Component/s: core
• Labels: pull-request-available
• Assignee: Danny Chen
• Reporter: Danny Chen
• Created: 19/Jun/20 03:11
• Updated: 01/Jun/21 22:58
• Resolved: 16/Jul/20 10:23

Description

Currently, we only have simple normalization such as:

$2 = $1 => $1 = $2
$2 > $1 => $1 < $2

we can extend the logic to more like:

• put the complex predicates behind, like OR(OR(udf($1), $2), $3) => OR($3, OR(udf($1), $2))
• put the udf operand behind, like OR(udf($1), $2) => OR($2, udf($1))
• put the local variables that appears more frequently in the front, which is more user-friendly to code generation because the variable can be cached and reused.

Also note that, we should allows flexible configuration for switch this function on/off(not a system calcite property now) for downstream users and projects(because the normalization may have some performance trade-off).

Issue Links

• relates to: CALCITE-4629 RexNormalize.hashCode() throws NullPointerException
• links to: GitHub Pull Request #2065