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[5.1] Backport BAG failover fix. Ignore server provided failover partner. #3704

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Merged
merged 10 commits into from
Oct 28, 2025
Merged

[5.1] Backport BAG failover fix. Ignore server provided failover partner. #3704

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86658d8
Fix #3400, ignore server-provided failover partner (#3625)
mdaigle Sep 29, 2025
4daba6f
Fix compilation issues.
mdaigle Oct 20, 2025
6e2732e
Clean up duplicate line. Adjust app context switch logic to match exi…
mdaigle Oct 20, 2025
2993c94
Review changes.
mdaigle Oct 22, 2025
0affc99
Add test case. Doesn't compile.
mdaigle Oct 22, 2025
46bbba8
Adjust usage of test servers and app context.
mdaigle Oct 22, 2025
1ed3411
Add failover and prelogin count capabilities to test server. Update t…
mdaigle Oct 22, 2025
16cefc4
Set backing field using reflection.
mdaigle Oct 22, 2025
6a5234c
Try clearing pool to make test more reliable.
mdaigle Oct 23, 2025
228009d
Use string.Empty
mdaigle Oct 23, 2025
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2 changes: 1 addition & 1 deletion src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/SqlClient/SqlCommand.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -3431,7 +3431,7 @@ private void CheckNotificationStateAndAutoEnlist()
}

Notification.Options = SqlDependency.GetDefaultComposedOptions(_activeConnection.DataSource,
InternalTdsConnection.ServerProvidedFailOverPartner,
InternalTdsConnection.ServerProvidedFailoverPartner,
identityUserName, _activeConnection.Database);
}

Expand Down
59 changes: 36 additions & 23 deletions ...Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/SqlClient/SqlInternalConnectionTds.cs
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Expand Up @@ -300,7 +300,6 @@ internal SessionData CurrentSessionData
// FOR CONNECTION RESET MANAGEMENT
private bool _fResetConnection;
private string _originalDatabase;
private string _currentFailoverPartner; // only set by ENV change from server
private string _originalLanguage;
private string _currentLanguage;
private int _currentPacketSize;
Expand Down Expand Up @@ -667,13 +666,7 @@ internal TdsParser Parser
}
}

internal string ServerProvidedFailOverPartner
{
get
{
return _currentFailoverPartner;
}
}
internal string ServerProvidedFailoverPartner { get; private set; }

internal SqlConnectionPoolGroupProviderInfo PoolGroupProviderInfo
{
Expand Down Expand Up @@ -1533,7 +1526,7 @@ private void LoginNoFailover(ServerInfo serverInfo,
!connectionOptions.MultiSubnetFailover, // ignore timeout for SniOpen call unless MSF
connectionOptions.MultiSubnetFailover ? intervalTimer : timeout);

if (connectionOptions.MultiSubnetFailover && null != ServerProvidedFailOverPartner)
if (connectionOptions.MultiSubnetFailover && ServerProvidedFailoverPartner != null)
{
// connection succeeded: trigger exception if server sends failover partner and MultiSubnetFailover is used
throw SQL.MultiSubnetFailoverWithFailoverPartner(serverProvidedFailoverPartner: true, internalConnection: this);
Expand Down Expand Up @@ -1561,7 +1554,7 @@ private void LoginNoFailover(ServerInfo serverInfo,
_currentPacketSize = ConnectionOptions.PacketSize;
_currentLanguage = _originalLanguage = ConnectionOptions.CurrentLanguage;
CurrentDatabase = _originalDatabase = ConnectionOptions.InitialCatalog;
_currentFailoverPartner = null;
ServerProvidedFailoverPartner = null;
_instanceName = string.Empty;

routingAttempts++;
Expand Down Expand Up @@ -1599,7 +1592,7 @@ private void LoginNoFailover(ServerInfo serverInfo,
// We only get here when we failed to connect, but are going to re-try

// Switch to failover logic if the server provided a partner
if (null != ServerProvidedFailOverPartner)
if (ServerProvidedFailoverPartner != null)
{
if (connectionOptions.MultiSubnetFailover)
{
Expand All @@ -1615,7 +1608,7 @@ private void LoginNoFailover(ServerInfo serverInfo,
LoginWithFailover(
true, // start by using failover partner, since we already failed to connect to the primary
serverInfo,
ServerProvidedFailOverPartner,
ServerProvidedFailoverPartner,
newPassword,
newSecurePassword,
redirectedUserInstance,
Expand All @@ -1637,8 +1630,13 @@ private void LoginNoFailover(ServerInfo serverInfo,
{
// We must wait for CompleteLogin to finish for to have the
// env change from the server to know its designated failover
// partner; save this information in _currentFailoverPartner.
PoolGroupProviderInfo.FailoverCheck(false, connectionOptions, ServerProvidedFailOverPartner);
// partner; save this information in ServerProvidedFailoverPartner.

// When ignoring server provided failover partner, we must pass in the original failover partner from the connection string.
// Otherwise the pool group's failover partner designation will be updated to point to the server provided value.
string actualFailoverPartner = LocalAppContextSwitches.IgnoreServerProvidedFailoverPartner ? "" : ServerProvidedFailoverPartner;

PoolGroupProviderInfo.FailoverCheck(false, connectionOptions, actualFailoverPartner);
}
CurrentDataSource = originalServerInfo.UserServerName;
}
Expand Down Expand Up @@ -1699,7 +1697,7 @@ TimeoutTimer timeout
ServerInfo failoverServerInfo = new ServerInfo(connectionOptions, failoverHost, connectionOptions.FailoverPartnerSPN);

ResolveExtendedServerName(primaryServerInfo, !redirectedUserInstance, connectionOptions);
if (null == ServerProvidedFailOverPartner)
if (ServerProvidedFailoverPartner == null)
{
ResolveExtendedServerName(failoverServerInfo, !redirectedUserInstance && failoverHost != primaryServerInfo.UserServerName, connectionOptions);
}
Expand Down Expand Up @@ -1747,12 +1745,21 @@ TimeoutTimer timeout
ServerInfo currentServerInfo;
if (useFailoverHost)
{
// Primary server may give us a different failover partner than the connection string indicates. Update it
if (null != ServerProvidedFailOverPartner && failoverServerInfo.ResolvedServerName != ServerProvidedFailOverPartner)
// Primary server may give us a different failover partner than the connection string indicates.
// Update it only if we are respecting server-provided failover partner values.
if (ServerProvidedFailoverPartner != null && failoverServerInfo.ResolvedServerName != ServerProvidedFailoverPartner)
{
SqlClientEventSource.Log.TryAdvancedTraceEvent("<sc.SqlInternalConnectionTds.LoginWithFailover|ADV> {0}, new failover partner={1}", ObjectID, ServerProvidedFailOverPartner);
failoverServerInfo.SetDerivedNames(string.Empty, ServerProvidedFailOverPartner);
if (LocalAppContextSwitches.IgnoreServerProvidedFailoverPartner)
{
SqlClientEventSource.Log.TryTraceEvent("<sc.SqlInternalConnectionTds.LoginWithFailover|ADV> {0}, Ignoring server provided failover partner '{1}' due to IgnoreServerProvidedFailoverPartner AppContext switch.", ObjectID, ServerProvidedFailoverPartner);
}
else
{
SqlClientEventSource.Log.TryAdvancedTraceEvent("<sc.SqlInternalConnectionTds.LoginWithFailover|ADV> {0}, new failover partner={1}", ObjectID, ServerProvidedFailoverPartner);
failoverServerInfo.SetDerivedNames(string.Empty, ServerProvidedFailoverPartner);
}
}

currentServerInfo = failoverServerInfo;
_timeoutErrorInternal.SetInternalSourceType(SqlConnectionInternalSourceType.Failover);
}
Expand Down Expand Up @@ -1834,7 +1841,7 @@ TimeoutTimer timeout
_activeDirectoryAuthTimeoutRetryHelper.State = ActiveDirectoryAuthenticationTimeoutRetryState.HasLoggedIn;

// if connected to failover host, but said host doesn't have DbMirroring set up, throw an error
if (useFailoverHost && null == ServerProvidedFailOverPartner)
if (useFailoverHost && ServerProvidedFailoverPartner == null)
{
throw SQL.InvalidPartnerConfiguration(failoverHost, CurrentDatabase);
}
Expand All @@ -1843,8 +1850,13 @@ TimeoutTimer timeout
{
// We must wait for CompleteLogin to finish for to have the
// env change from the server to know its designated failover
// partner; save this information in _currentFailoverPartner.
PoolGroupProviderInfo.FailoverCheck(useFailoverHost, connectionOptions, ServerProvidedFailOverPartner);
// partner.

// When ignoring server provided failover partner, we must pass in the original failover partner from the connection string.
// Otherwise the pool group's failover partner designation will be updated to point to the server provided value.
string actualFailoverPartner = LocalAppContextSwitches.IgnoreServerProvidedFailoverPartner ? failoverHost : ServerProvidedFailoverPartner;

PoolGroupProviderInfo.FailoverCheck(useFailoverHost, connectionOptions, actualFailoverPartner);
}
CurrentDataSource = (useFailoverHost ? failoverHost : primaryServerInfo.UserServerName);
}
Expand Down Expand Up @@ -2068,7 +2080,8 @@ internal void OnEnvChange(SqlEnvChange rec)
{
throw SQL.ROR_FailoverNotSupportedServer(this);
}
_currentFailoverPartner = rec._newValue;

ServerProvidedFailoverPartner = rec._newValue;
break;

case TdsEnums.ENV_PROMOTETRANSACTION:
Expand Down
2 changes: 1 addition & 1 deletion src/Microsoft.Data.SqlClient/netfx/src/Microsoft/Data/SqlClient/SqlCommand.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -3814,7 +3814,7 @@ private void CheckNotificationStateAndAutoEnlist()
}

Notification.Options = SqlDependency.GetDefaultComposedOptions(_activeConnection.DataSource,
InternalTdsConnection.ServerProvidedFailOverPartner,
InternalTdsConnection.ServerProvidedFailoverPartner,
identityUserName, _activeConnection.Database);
}

Expand Down
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