Assume that you use a one-way send port that uses the Microsoft Windows Communication Foundation (WCF)-based SQL Adapter in Microsoft BizTalk Server 2010 or in Microsoft BizTalk Server 2013 to process messages. After some time, you receive the following error message:
The timeout period elapsed prior to obtaining a connection from the pool. This may have occurred because all pooled connections were in use and max pool size was reached.
This issue occurs because the related SQL connection in the SQL adapter is not released when the message processing generates the results.
Connections are only released back into the connection pool when the BizTalk host instance is recycled. When the connection buildup exceeds the specified MaxConnectionPoolSize value of the connection pool, you will receive the above error message.
This issue occurs when you use one-way send ports.
Cumulative update package information
For BizTalk Server 2013
The hotfix that resolves this issue is included in cumulative update package 2 for BizTalk Server 2013.
For more information about how to obtain the cumulative update package, click the following article number to view the article in the Microsoft Knowledge Base:
2892599 Cumulative update package 2 for BizTalk Server 2013
For BizTalk Server 2010
The hotfix that resolves this issue is included in cumulative update package 6 for BizTalk 2010.
For more information about how to obtain this cumulative update package, click the following article number to view the article in the Microsoft Knowledge Base:
2855367 Cumulative update package 6 for BizTalk Server 2010
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For more information about the MaxConnectionPoolSize binding property, go to the following MSDN website:
Working with BizTalk Adapter for SQL Server Binding Properties
For more information about BizTalk Server hotfixes, click the following article number to view the article in the Microsoft Knowledge Base:
2003907 Information about BizTalk Server hotfixes