cherry pick pingcap#33519 to release-5.3

Signed-off-by: ti-srebot <ti-srebot@pingcap.com>

planner/core/cache.go

@@ -201,7 +201,6 @@ func NewPSTMTPlanCacheValue(plan Plan, names []*types.FieldName, srcMap map[*mod
 type CachedPrepareStmt struct {
 	PreparedAst         *ast.Prepared
 	VisitInfos          []visitInfo
-	ColumnInfos         interface{}
 	Executor            interface{}
 	NormalizedSQL       string
 	NormalizedPlan      string

server/driver_tidb.go

@@ -79,8 +79,7 @@ func (ts *TiDBStatement) Execute(ctx context.Context, args []types.Datum) (rs Re
 		return
 	}
 	rs = &tidbResultSet{
-		recordSet:    tidbRecordset,
-		preparedStmt: ts.ctx.GetSessionVars().PreparedStmts[ts.id].(*core.CachedPrepareStmt),
+		recordSet: tidbRecordset,
 	}
 	return
 }
@@ -291,11 +290,10 @@ func (tc *TiDBContext) Prepare(sql string) (statement PreparedStatement, columns
 }
 
 type tidbResultSet struct {
-	recordSet    sqlexec.RecordSet
-	columns      []*ColumnInfo
-	rows         []chunk.Row
-	closed       int32
-	preparedStmt *core.CachedPrepareStmt
+	recordSet sqlexec.RecordSet
+	columns   []*ColumnInfo
+	rows      []chunk.Row
+	closed    int32
 }
 
 func (trs *tidbResultSet) NewChunk() *chunk.Chunk {
@@ -337,23 +335,12 @@ func (trs *tidbResultSet) Columns() []*ColumnInfo {
 	if trs.columns != nil {
 		return trs.columns
 	}
-	// for prepare statement, try to get cached columnInfo array
-	if trs.preparedStmt != nil {
-		ps := trs.preparedStmt
-		if colInfos, ok := ps.ColumnInfos.([]*ColumnInfo); ok {
-			trs.columns = colInfos
-		}
-	}
+
 	if trs.columns == nil {
 		fields := trs.recordSet.Fields()
 		for _, v := range fields {
 			trs.columns = append(trs.columns, convertColumnInfo(v))
 		}
-		if trs.preparedStmt != nil {
-			// if ColumnInfo struct has allocated object,
-			// here maybe we need deep copy ColumnInfo to do caching
-			trs.preparedStmt.ColumnInfos = trs.columns
-		}
 	}
 	return trs.columns
 }