The semaphore timeout period has expired and not sure what to do? Read on to find out how to solve the SQL error 121.

At Bobcares, we offer solutions for every query, big and small, as a part of our Server Management Services.

Let’s take a look at how our Support Team is ready to help customers when the semaphore timeout period has expired.

How to resolve: The semaphore timeout period has expired

One of our customers recently found themselves facing the following error while executing a T-SQL script:

A transport-level error has occurred when receiving results from the server. (provider: TCP Provider, error: 0 – The semaphore timeout period has expired.) (Microsoft SQL Server, Error:121)

According to our proficient Support Team, this error is due to unstable network connectivity. The unstable network may be due to various parameters like:

• Incorrect TCP\IP settings
• Inappropriate network packet size configured in SQL Server
• Improperly configured TCP Chimney Offload
• Network Interface Card (NIC) driver issue

Our Support Team has put together this guide to help you troubleshoot the reason behind the unstable network.

How to check TCP\IP Settings

1. First, open the SQL Server configuration manager and verify the TCP configuration settings.
2. Then, verify all the settings on the SQL Server Network configuration settings as well.

If you require further assistance, this article will come in handy.

How to review Network Packet Size

The next troubleshooting tip involves reviewing the network packet size configuration in SQL Server. Preferably, it is better to stick to the default value and change it only if we have a particular requirement to change network packet size. We can change the value easily by referring to this article.

How to review TCP Chimney Offload

In case we are facing a network-related connectivity issue it is essential to review the TCP Chimney Offload setting. It is a networking technology responsible for transferring the workload from the CPU to a network adapter for the duration of the network data transfer. We can either enable or disable this feature at both of the following locations:

• Operating system
• Advanced properties page of the network adapter

Our Support Techs would like to point out that the TCP Chimney Offload features works only if we enable the feature at both locations. It is usually disabled by default at both these locations. However, OEM installation tends to enable the feature in the operating system, network adapter, or both.

How to validate Network related Driver Issues

This troubleshooting tip involves validating all the drivers at the OS and network layer by checking whether they are up-to-date and have no issue. In case we find any issue at any layer, we have to update the drivers.

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Conclusion

In conclusion, our skilled Support Techs at Bobcares demonstrated what to do when the semaphore timeout period has expired and you come across SQL error 121.