From 0a0d676bb2799f9d6f617008c6c29f9213875806 Mon Sep 17 00:00:00 2001
From: crazycs <crazycs520@gmail.com>
Date: Sun, 30 Sep 2018 11:42:06 +0800
Subject: [PATCH] admin: fix admin check table compare bug (#7818)

---
 executor/admin_test.go |  8 ++++++++
 util/admin/admin.go    | 22 +++++++++++++++++++++-
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/executor/admin_test.go b/executor/admin_test.go
index c3f078257285f..0a1282c582388 100644
--- a/executor/admin_test.go
+++ b/executor/admin_test.go
@@ -498,6 +498,14 @@ func (s *testSuite) TestAdminCheckTable(c *C) {
 	tk.MustExec(`ALTER TABLE t1 ADD INDEX idx5 (c5)`)
 	tk.MustExec(`ALTER TABLE t1 ADD INDEX idx6 (c6)`)
 	tk.MustExec(`admin check table t1`)
+
+	// Test add index on decimal column.
+	tk.MustExec(`drop table if exists td1;`)
+	tk.MustExec(`CREATE TABLE td1 (c2 INT NULL DEFAULT '70');`)
+	tk.MustExec(`INSERT INTO td1 SET c2 = '5';`)
+	tk.MustExec(`ALTER TABLE td1 ADD COLUMN c4 DECIMAL(12,8) NULL DEFAULT '213.41598062';`)
+	tk.MustExec(`ALTER TABLE td1 ADD INDEX id2 (c4) ;`)
+	tk.MustExec(`ADMIN CHECK TABLE td1;`)
 }
 
 func (s *testSuite) TestAdminCheckPrimaryIndex(c *C) {
diff --git a/util/admin/admin.go b/util/admin/admin.go
index d71434e7bcf3b..3e767f73021d3 100644
--- a/util/admin/admin.go
+++ b/util/admin/admin.go
@@ -353,6 +353,7 @@ func checkIndexAndRecord(sessCtx sessionctx.Context, txn kv.Transaction, t table
 	if err != nil {
 		return errors.Trace(err)
 	}
+	sc := new(stmtctx.StatementContext)
 	for {
 		vals1, h, err := it.Next()
 		if terror.ErrorEqual(err, io.EOF) {
@@ -375,7 +376,7 @@ func checkIndexAndRecord(sessCtx sessionctx.Context, txn kv.Transaction, t table
 			return errors.Trace(err)
 		}
 		adjustDatumKind(vals1, vals2)
-		if !reflect.DeepEqual(vals1, vals2) {
+		if !compareDatumSlice(sc, vals1, vals2) {
 			record1 := &RecordData{Handle: h, Values: vals1}
 			record2 := &RecordData{Handle: h, Values: vals2}
 			return ErrDataInConsistent.GenWithStack("index:%#v != record:%#v", record1, record2)
@@ -385,6 +386,25 @@ func checkIndexAndRecord(sessCtx sessionctx.Context, txn kv.Transaction, t table
 	return nil
 }
 
+func compareDatumSlice(sc *stmtctx.StatementContext, val1s, val2s []types.Datum) bool {
+	if len(val1s) != len(val2s) {
+		return false
+	}
+	for i, v := range val1s {
+		if v.Kind() == types.KindMysqlDecimal {
+			res, err := v.CompareDatum(sc, &val2s[i])
+			if err != nil || res != 0 {
+				return false
+			}
+		} else {
+			if !reflect.DeepEqual(v, val2s[i]) {
+				return false
+			}
+		}
+	}
+	return true
+}
+
 // CheckRecordAndIndex is exported for testing.
 func CheckRecordAndIndex(sessCtx sessionctx.Context, txn kv.Transaction, t table.Table, idx table.Index, genExprs map[string]expression.Expression) error {
 	sc := sessCtx.GetSessionVars().StmtCtx