server: make call to ReleaseConnID idempotent. (#45676)

close #45675
pingcap · Jul 31, 2023 · 35e654e · 35e654e
1 parent fd50df6
commit 35e654e
Showing 1 changed file with 6 additions and 1 deletion.
diff --git a/server/conn.go b/server/conn.go
@@ -335,9 +335,14 @@ func (cc *clientConn) Close() error {
 	return closeConn(cc, connections)
 }
 
+// closeConn should be idempotent.
+// It will be called on the same `clientConn` more than once to avoid connection leak.
 func closeConn(cc *clientConn, connections int) error {
 	metrics.ConnGauge.Set(float64(connections))
-	cc.server.dom.ReleaseConnID(cc.connectionID)
+	if cc.connectionID > 0 {
+		cc.server.dom.ReleaseConnID(cc.connectionID)
+		cc.connectionID = 0
+	}
 	if cc.bufReadConn != nil {
 		err := cc.bufReadConn.Close()
 		if err != nil {