From 7fc6661a3415117c3bd0ed8ff7f49ea004216b37 Mon Sep 17 00:00:00 2001
From: ti-srebot <66930949+ti-srebot@users.noreply.github.com>
Date: Wed, 3 Aug 2022 15:56:06 +0800
Subject: [PATCH] ddl: invalid multiple MAXVALUE partitions (#36329) (#36345)
 (#36447)

close pingcap/tidb#36329
---
 ddl/db_partition_test.go | 8 ++++++++
 ddl/ddl_api.go           | 2 +-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/ddl/db_partition_test.go b/ddl/db_partition_test.go
index c17c9a648790f..16d2f22214925 100644
--- a/ddl/db_partition_test.go
+++ b/ddl/db_partition_test.go
@@ -550,6 +550,14 @@ create table log_message_1 (
 				"partition p1 values less than ('A'));",
 			dbterror.ErrRangeNotIncreasing,
 		},
+		{
+			"create table t(d datetime)" +
+				"partition by range columns (d) (" +
+				"partition p0 values less than ('2022-01-01')," +
+				"partition p1 values less than (MAXVALUE), " +
+				"partition p2 values less than (MAXVALUE));",
+			dbterror.ErrRangeNotIncreasing,
+		},
 		{
 			"CREATE TABLE t1(c0 INT) PARTITION BY HASH((NOT c0)) PARTITIONS 2;",
 			dbterror.ErrPartitionFunctionIsNotAllowed,
diff --git a/ddl/ddl_api.go b/ddl/ddl_api.go
index 27e509439d652..7c867b9b0b3d6 100644
--- a/ddl/ddl_api.go
+++ b/ddl/ddl_api.go
@@ -2704,7 +2704,7 @@ func checkTwoRangeColumns(ctx sessionctx.Context, curr, prev *model.PartitionDef
 	}
 	for i := 0; i < len(pi.Columns); i++ {
 		// Special handling for MAXVALUE.
-		if strings.EqualFold(curr.LessThan[i], partitionMaxValue) {
+		if strings.EqualFold(curr.LessThan[i], partitionMaxValue) && !strings.EqualFold(prev.LessThan[i], partitionMaxValue) {
 			// If current is maxvalue, it certainly >= previous.
 			return true, nil
 		}