expression: do not rewrite like to = if new collation is enabled (#…

…21893) (#22531)

Signed-off-by: ti-srebot <[email protected]>

planner/core/expression_rewriter.go

@@ -1449,8 +1449,8 @@ func (er *expressionRewriter) patternLikeToExpression(v *ast.PatternLikeExpr) {
 	var function expression.Expression
 	fieldType := &types.FieldType{}
 	isPatternExactMatch := false
-	// Treat predicate 'like' the same way as predicate '=' when it is an exact match.
-	if patExpression, ok := er.ctxStack[l-1].(*expression.Constant); ok {
+	// Treat predicate 'like' the same way as predicate '=' when it is an exact match and new collation is not enabled.
+	if patExpression, ok := er.ctxStack[l-1].(*expression.Constant); ok && !collate.NewCollationEnabled() {
 		patString, isNull, err := patExpression.EvalString(nil, chunk.Row{})
 		if err != nil {
 			er.err = err

util/ranger/ranger_test.go

@@ -384,14 +384,14 @@ create table t(
 		{
 			indexPos:    0,
 			exprStr:     "a LIKE 'abc'",
-			accessConds: "[eq(test.t.a, abc)]",
+			accessConds: "[like(test.t.a, abc, 92)]",
 			filterConds: "[]",
 			resultStr:   "[[\"abc\",\"abc\"]]",
 		},
 		{
 			indexPos:    0,
 			exprStr:     `a LIKE "ab\_c"`,
-			accessConds: "[eq(test.t.a, ab_c)]",
+			accessConds: "[like(test.t.a, ab\\_c, 92)]",
 			filterConds: "[]",
 			resultStr:   "[[\"ab_c\",\"ab_c\"]]",
 		},
@@ -405,14 +405,14 @@ create table t(
 		{
 			indexPos:    0,
 			exprStr:     `a LIKE '\%a'`,
-			accessConds: "[eq(test.t.a, %a)]",
+			accessConds: "[like(test.t.a, \\%a, 92)]",
 			filterConds: "[]",
 			resultStr:   `[["%a","%a"]]`,
 		},
 		{
 			indexPos:    0,
 			exprStr:     `a LIKE "\\"`,
-			accessConds: "[eq(test.t.a, \\)]",
+			accessConds: "[like(test.t.a, \\, 92)]",
 			filterConds: "[]",
 			resultStr:   "[[\"\\\",\"\\\"]]",
 		},