Enhance error message when coordinator not healthy (#15950)

Signed-off-by: Nxiaofan-luan <xiaofan.luan@zilliz.com>

internal/distributed/datacoord/client/client.go

@@ -81,7 +81,7 @@ func (c *Client) getDataCoordAddr() (string, error) {
 	ms, ok := msess[key]
 	if !ok {
 		log.Debug("DataCoordClient, not existed in msess ", zap.Any("key", key), zap.Any("len of msess", len(msess)))
-		return "", fmt.Errorf("number of datacoord is incorrect, %d", len(msess))
+		return "", fmt.Errorf("find no available datacoord, check datacoord state")
 	}
 	return ms.Address, nil
 }

internal/distributed/indexcoord/client/client.go

@@ -98,7 +98,7 @@ func (c *Client) getIndexCoordAddr() (string, error) {
 	ms, ok := msess[key]
 	if !ok {
 		log.Debug("IndexCoordClient msess key not existed", zap.Any("key", key), zap.Any("len of msess", len(msess)))
-		return "", fmt.Errorf("number of indexcoord is incorrect, %d", len(msess))
+		return "", fmt.Errorf("find no available indexcoord, check indexcoord state")
 	}
 	return ms.Address, nil
 }

internal/distributed/querycoord/client/client.go

@@ -81,7 +81,7 @@ func (c *Client) getQueryCoordAddr() (string, error) {
 	ms, ok := msess[key]
 	if !ok {
 		log.Debug("QueryCoordClient msess key not existed", zap.Any("key", key))
-		return "", fmt.Errorf("number of querycoord is incorrect, %d", len(msess))
+		return "", fmt.Errorf("find no available querycoord, check querycoord state")
 	}
 	return ms.Address, nil
 }

internal/distributed/rootcoord/client/client.go

@@ -91,7 +91,7 @@ func (c *Client) getRootCoordAddr() (string, error) {
 	ms, ok := msess[key]
 	if !ok {
 		log.Warn("RootCoordClient mess key not exist", zap.Any("key", key))
-		return "", fmt.Errorf("number of RootCoord is incorrect, %d", len(msess))
+		return "", fmt.Errorf("find no available rootcoord, check rootcoord state")
 	}
 	log.Debug("RootCoordClient GetSessions success", zap.String("address", ms.Address))
 	return ms.Address, nil