68 lines
2.7 KiB
Markdown
68 lines
2.7 KiB
Markdown
## Connection pool blocking period for Azure SQL databases is removed
|
|
|
|
### Scope
|
|
Minor
|
|
|
|
### Version Introduced
|
|
4.6.2
|
|
|
|
### Source Analyzer Status
|
|
Investigating
|
|
|
|
### Change Description
|
|
Starting with the .NET Framework 4.6.2, for connection open requests to known
|
|
Azure SQL databases (\*.database.windows.net, \*.database.chinacloudapi.cn,
|
|
\*.database.usgovcloudapi.net, \*.database.cloudapi.de), the connection pool
|
|
blocking period is removed, and connection open errors are not cached. Attempts
|
|
to retry connection open requests will occur almost immediately after transient
|
|
connection errors. This change allows the connection open attempt to be retried
|
|
immediately for Azure SQL databases, thereby improving the performance of cloud-
|
|
enabled apps. For all other connection attempts, the connection pool blocking
|
|
period continues to be enforced.<p/>
|
|
|
|
In the .NET Framework 4.6.1 and earlier versions, when an app encounters a
|
|
transient connection failure when connecting to a database, the connection
|
|
attempt cannot be retried quickly, because the connection pool caches the error
|
|
and re-throws it for 5 seconds to 1 minute. For more information, see
|
|
[SQL Server Connection Pooling (ADO.NET)](~/docs/framework/data/adonet/sql-server-connection-pooling.md).
|
|
This behavior is problematic for connections to Azure SQL databases, which often
|
|
fail with transient errors that are typically recovered from within a few
|
|
seconds. The connection pool blocking feature means that the app cannot connect
|
|
to the database for an extensive period, even though the database is available
|
|
and the app needs to render within a few seconds.
|
|
|
|
- [ ] Quirked
|
|
- [ ] Build-time break
|
|
|
|
### Recommended Action
|
|
|
|
If this behavior is undesirable, the connection pool blocking period can be
|
|
configured by setting the <xref:System.Data.SqlClient.SqlConnectionStringBuilder.PoolBlockingPeriod?displayProperty=name>
|
|
property introduced in the .NET Framework 4.6.2. The value of the property is a
|
|
member of the
|
|
<xref:System.Data.SqlClient.PoolBlockingPeriod?displayProperty=name> enumeration
|
|
that can take either of three values:
|
|
|
|
- <xref:System.Data.SqlClient.PoolBlockingPeriod.AlwaysBlock>
|
|
- <xref:System.Data.SqlClient.PoolBlockingPeriod.Auto>
|
|
- <xref:System.Data.SqlClient.PoolBlockingPeriod.NeverBlock>
|
|
|
|
The previous behavior can be restored by setting the
|
|
<xref:System.Data.SqlClient.SqlConnectionStringBuilder.PoolBlockingPeriod?displayProperty=name>
|
|
property to <xref:System.Data.SqlClient.PoolBlockingPeriod.AlwaysBlock>.
|
|
|
|
### Affected APIs
|
|
- `M:System.Data.Common.DbConnection.OpenAsync`
|
|
- `M:System.Data.SqlClient.SqlConnection.Open`
|
|
- `M:System.Data.SqlClient.SqlConnection.OpenAsync(System.Threading.CancellationToken)`
|
|
|
|
### Category
|
|
Data
|
|
|
|
<!--
|
|
### Original Bug
|
|
213479
|
|
-->
|
|
|
|
<!-- breaking change id: 160 -->
|