router: avoid deadlock in rebalance (#817) (#818)

ti-chi-bot · djshow832 · web-flow · commit d69a26361f6d · 2025-06-13T01:45:40.000Z
Co-authored-by: djshow832 &lt;zhangming@pingcap.com&gt;
diff --git a/pkg/balance/router/router_score.go b/pkg/balance/router/router_score.go
@@ -393,7 +393,6 @@ func (router *ScoreBasedRouter) redirectConn(conn *connWrapper, fromBackend *bac
 		zap.String("to", toBackend.addr),
 	}
 	fields = append(fields, logFields...)
-	fields = append(fields, conn.ConnInfo()...)
 	succeed := conn.Redirect(toBackend)
 	if succeed {
 		router.logger.Debug("begin redirect connection", fields...)
diff --git a/pkg/proxy/backend/backend_conn_mgr.go b/pkg/proxy/backend/backend_conn_mgr.go
@@ -838,6 +838,7 @@ func (mgr *BackendConnManager) UpdateLogger(fields ...zap.Field) {
 }
 
 // ConnInfo returns detailed info of the connection, which should not be logged too many times.
+// Be careful about deadlocks.
 func (mgr *BackendConnManager) ConnInfo() []zap.Field {
 	mgr.processLock.Lock()
 	var fields []zap.Field

Original file line number	Diff line number	Diff line change
`@@ -393,7 +393,6 @@ func (router ScoreBasedRouter) redirectConn(conn connWrapper, fromBackend *bac`
`393`	`393`	`zap.String("to", toBackend.addr),`
`394`	`394`	`}`
`395`	`395`	`fields = append(fields, logFields...)`
`396`		`- fields = append(fields, conn.ConnInfo()...)`
`397`	`396`	`succeed := conn.Redirect(toBackend)`
`398`	`397`	`if succeed {`
`399`	`398`	`router.logger.Debug("begin redirect connection", fields...)`
Original file line number	Diff line number	Diff line change
`@@ -838,6 +838,7 @@ func (mgr *BackendConnManager) UpdateLogger(fields ...zap.Field) {`
`838`	`838`	`}`
`839`	`839`
`840`	`840`	`// ConnInfo returns detailed info of the connection, which should not be logged too many times.`
	`841`	`+// Be careful about deadlocks.`
`841`	`842`	`func (mgr *BackendConnManager) ConnInfo() []zap.Field {`
`842`	`843`	`mgr.processLock.Lock()`
`843`	`844`	`var fields []zap.Field`