Error: 525, Message: Scalearc: Connection timedout in Server Queue.
You sometime receive following error when Application attempts to establish connections to ScaleArc in alert log.
Error: 525, Message: Scalearc: Connection timedout in Server Queue, Type: 45
This alert log error indicates that ScaleArc was not able to serve the application connection to any database server.
When ScaleArc received a first query in client connection, a new server connection must be associated with the client connection. If ScaleArc is not able to associate such connection, it is put in Surge Queue to wait for any server connection becoming available.
ScaleArc prompts error and terminates client connection if no server connection becomes available within Surge Queue Timeout.
If this error is observed frequently, then please consider to taken an appropriate action depending on its root cause.
Case 1. Max Concurrent Server Connection is reached
Please increase Max Concurrent Server Conneciton if its database server has room to accept more number of connections from ScaleArc.
ScaleArc is no longer able to open new connection against database server if Max Concurrent Server Connection is reached. Subsequenty, all following connections are put in Surge Queue. This can be confirmed at Server Connection graph in LIVE MONITOR->Historical Stats.
Case 2. AutoFailover has been triggerred
Please increase Surge Queue Timeout value in order to ensure that ScaleArc can hold connections until AutoFailover completes.ScaleArc is not able to associate client connection with server connection if its target server is marked as unhealthy. Subsequently, all following connections are put in Surge Queue.
If AutoFailover is configured, ScaleArc performs AutoFailover to promote Standby server to Read + Write role.
Case 3. When RW Split is ON and No Read Write Role DB Server is present in the Cluster
SQL Traffic ScaleArc detect as Write and no Read+Write Rold DB Server present in the Cluster, ScaleArc put those connections in Surge Queue and ultimately those connections got timedOut in Surge Queue beacause of the non availbality of the Read+Write DB role in the Cluster.
- KB#2826: Functional Spec: Surge Queue Timeout
- KB#2829: Functional Spec: Max Concurrent Server Connection
If you are experiencing issues with ScaleArc or with any of it's features, please contact ScaleArc Support. We are available 24x7 by phone at 855 800 7225 or +1 408 412 7315. For general support inquiries, you can also e-mail us at email@example.com.
2901 Tasman Drive Santa Clara, CA 95054 | Email: firstname.lastname@example.org