Merge pull request #9014 from planetscale/sql_mode-change-validation

handle sql_mode differently for new value change validation
vitessio · Oct 19, 2021 · 315d907 · 315d907
2 parents a7d542f + 87ec407
commit 315d907
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Showing 3 changed files with 384 additions and 205 deletions.
diff --git a/go/vt/vtgate/engine/set.go b/go/vt/vtgate/engine/set.go
@@ -327,6 +327,9 @@ func (svs *SysVarReservedConn) execSetStatement(vcursor VCursor, rss []*srvtopo.
 
 func (svs *SysVarReservedConn) checkAndUpdateSysVar(vcursor VCursor, res evalengine.ExpressionEnv) (bool, error) {
 	sysVarExprValidationQuery := fmt.Sprintf("select %s from dual where @@%s != %s", svs.Expr, svs.Name, svs.Expr)
+	if svs.Name == "sql_mode" {
+		sysVarExprValidationQuery = fmt.Sprintf("select @@%s orig, %s new", svs.Name, svs.Expr)
+	}
 	rss, _, err := vcursor.ResolveDestinations(svs.Keyspace.Name, nil, []key.Destination{key.DestinationKeyspaceID{0}})
 	if err != nil {
 		return false, err
@@ -335,18 +338,69 @@ func (svs *SysVarReservedConn) checkAndUpdateSysVar(vcursor VCursor, res evaleng
 	if err != nil {
 		return false, err
 	}
-	if len(qr.Rows) == 0 {
+	changed := len(qr.Rows) > 0
+	if !changed {
 		return false, nil
 	}
-	// TODO : validate how value needs to be stored.
-	value := qr.Rows[0][0]
+
+	var value sqltypes.Value
+	if svs.Name == "sql_mode" {
+		changed, value = sqlModeChangedValue(qr)
+		if !changed {
+			return false, nil
+		}
+	} else {
+		value = qr.Rows[0][0]
+	}
 	buf := new(bytes.Buffer)
 	value.EncodeSQL(buf)
 	vcursor.Session().SetSysVar(svs.Name, buf.String())
 	vcursor.Session().NeedsReservedConn()
 	return true, nil
 }
 
+func sqlModeChangedValue(qr *sqltypes.Result) (bool, sqltypes.Value) {
+	if len(qr.Fields) != 2 {
+		return false, sqltypes.Value{}
+	}
+	if len(qr.Rows[0]) != 2 {
+		return false, sqltypes.Value{}
+	}
+	orig := qr.Rows[0][0].ToString()
+	newVal := qr.Rows[0][1].ToString()
+
+	origArr := strings.Split(orig, ",")
+	// Keep track of if the value is seen or not.
+	origMap := map[string]bool{}
+	for _, oVal := range origArr {
+		// Default is not seen.
+		origMap[strings.ToUpper(oVal)] = true
+	}
+	uniqOrigVal := len(origMap)
+	origValSeen := 0
+
+	changed := false
+	newValArr := strings.Split(newVal, ",")
+	for _, nVal := range newValArr {
+		nVal = strings.ToUpper(nVal)
+		notSeen, exists := origMap[nVal]
+		if !exists {
+			changed = true
+			break
+		}
+		if exists && notSeen {
+			// Value seen. Turn it off
+			origMap[nVal] = false
+			origValSeen++
+		}
+	}
+	if !changed && uniqOrigVal != origValSeen {
+		changed = true
+	}
+
+	return changed, qr.Rows[0][1]
+}
+
 var _ SetOp = (*SysVarSetAware)(nil)
 
 // MarshalJSON marshals all the json