vlsi commented on a change in pull request #1740: [CALCITE-3713] Remove column
names from Project#digest
URL: https://github.com/apache/calcite/pull/1740#discussion_r365115741
##########
File path: core/src/main/java/org/apache/calcite/rex/RexCall.java
##########
@@ -127,11 +137,83 @@ protected final StringBuilder
appendOperands(StringBuilder sb) {
includeType = RexDigestIncludeType.NO_TYPE;
}
}
- sb.append(((RexLiteral) operand).computeDigest(includeType));
+ operandDigests.add(((RexLiteral) operand).computeDigest(includeType));
+ }
+ int totalLength = (operandDigests.size() - 1) * 2; // commas
+ for (String s : operandDigests) {
+ totalLength += s.length();
+ }
+ sb.ensureCapacity(sb.length() + totalLength);
+ sortOperandsIfNeeded(sb, operands, operandDigests);
+ for (int i = 0; i < operandDigests.size(); i++) {
+ String op = operandDigests.get(i);
+ if (i != 0) {
+ sb.append(", ");
+ }
+ sb.append(op);
}
return sb;
}
+ private void sortOperandsIfNeeded(StringBuilder sb,
+ List<RexNode> operands, List<String> operandDigests) {
+ if (operands.isEmpty() || !needNormalize()) {
+ return;
+ }
+ final SqlKind kind = op.getKind();
+ if (SqlKind.SYMMETRICAL_SAME_ARG_TYPE.contains(kind)) {
+ final RelDataType firstType = operands.get(0).getType();
+ for (int i = 1; i < operands.size(); i++) {
+ if (!equalSansNullability(firstType, operands.get(i).getType())) {
+ // Arguments have different type, thus they must not be sorted
Review comment:
Do we want to support strict floating-point non-associativity here?
Technically speaking, `PLUS` for FLOATs is not associative :(
https://stackoverflow.com/a/10371890/1261287
>i means to support more reordering for PLUS and TIMES even their operands
types are differen
I wanted the first iteration to be as simple as it could be.
Proper cost estimates are more interesting for me than spending time on
`DECIMAL(3,0) + DECIMAL(5,0)` normalization.
Reordering of `DECIMAL(3,0) + DECIMAL(5,0)` might be tricky, especially if
it is nested: `DECIMAL(3,0) + DECIMAL(3,0) + DECIMAL(5,0)` might probably
return different result than `DECIMAL(5,0) + DECIMAL(3,0) + DECIMAL(3,0)`, so I
don't want to spend time on exploring those scenarios as they are quite rare
for me.
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