When using SchemaComparison with two dacpacs, DacFX takes a long time and throws lots of SocketExceptions

# Issue

When comparing two dacpacs located on the local file system, DacFx tries to open a SQL connection to a unexisting SQL Server database. It fails consistently with Socket Exception and this lasts for several minutes until it gives up and continues onto doing the comparison.

This is independent of the dacpacs provided. A simple dacpac with a single table compared with an empty dacpac surfaces this behavior.

The comparison is performed correctly, but the extra minutes spent trying to connect to a database that does not exist causes significant delays to the comparison process.

We use DacFx to run comparisons in our build system to verify for breaking changes, and this is adding delays to our build pipeline.

# Version

```xml

```

```
[andre@scout ~]$ dotnet --version
3.1.108
```

# Example

```csharp
// sourceDacpacPath and targetDacpacPath are two local paths to the local file system
var source = new SchemaCompareDacpacEndpoint(sourceDacpacPath);
var target = new SchemaCompareDacpacEndpoint(targetDacpacPath);
var comparison = new SchemaComparison(source, target);
this.schemaComparison.Compare(); // several minutes throwing and internally catching socket exception before this return
```

# Call Stack

```
System.Net.Sockets.dll!System.Net.Sockets.Socket.DoConnect(System.Net.EndPoint endPointSnapshot, System.Net.Internals.SocketAddress socketAddress) (Unknown Source:0)
System.Net.Sockets.dll!System.Net.Sockets.Socket.Connect(System.Net.EndPoint remoteEP) (Unknown Source:0)
System.Net.Sockets.dll!System.Net.Sockets.Socket.Connect(System.Net.IPAddress address, int port) (Unknown Source:0)
System.Data.SqlClient.dll!System.Data.SqlClient.SNI.SNITCPHandle.Connect(string serverName, int port, System.TimeSpan timeout) (Unknown Source:0)
System.Data.SqlClient.dll!System.Data.SqlClient.SNI.SNITCPHandle.SNITCPHandle(string serverName, int port, long timerExpire, object callbackObject, bool parallel) (Unknown Source:0)
System.Data.SqlClient.dll!System.Data.SqlClient.SNI.SNIProxy.CreateTcpHandle(System.Data.SqlClient.SNI.DataSource details, long timerExpire, object callbackObject, bool parallel) (Unknown Source:0)
System.Data.SqlClient.dll!System.Data.SqlClient.SNI.SNIProxy.CreateConnectionHandle(object callbackObject, string fullServerName, bool ignoreSniOpenTimeout, long timerExpire, out byte[] instanceName, ref byte[] spnBuffer, bool flushCache, bool async, bool parallel, bool isIntegratedSecurity) (Unknown Source:0)
System.Data.SqlClient.dll!System.Data.SqlClient.SNI.TdsParserStateObjectManaged.CreatePhysicalSNIHandle(string serverName, bool ignoreSniOpenTimeout, long timerExpire, out byte[] instanceName, ref byte[] spnBuffer, bool flushCache, bool async, bool parallel, bool isIntegratedSecurity) (Unknown Source:0)
System.Data.SqlClient.dll!System.Data.SqlClient.TdsParser.Connect(System.Data.SqlClient.ServerInfo serverInfo, System.Data.SqlClient.SqlInternalConnectionTds connHandler, bool ignoreSniOpenTimeout, long timerExpire, bool encrypt, bool trustServerCert, bool integratedSecurity, bool withFailover) (Unknown Source:0)
System.Data.SqlClient.dll!System.Data.SqlClient.SqlInternalConnectionTds.AttemptOneLogin(System.Data.SqlClient.ServerInfo serverInfo, string newPassword, System.Security.SecureString newSecurePassword, bool ignoreSniOpenTimeout, System.Data.ProviderBase.TimeoutTimer timeout, bool withFailover) (Unknown Source:0)
System.Data.SqlClient.dll!System.Data.SqlClient.SqlInternalConnectionTds.LoginNoFailover(System.Data.SqlClient.ServerInfo serverInfo, string newPassword, System.Security.SecureString newSecurePassword, bool redirectedUserInstance, System.Data.SqlClient.SqlConnectionString connectionOptions, System.Data.SqlClient.SqlCredential credential, System.Data.ProviderBase.TimeoutTimer timeout) (Unknown Source:0)
System.Data.SqlClient.dll!System.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(System.Data.ProviderBase.TimeoutTimer timeout, System.Data.SqlClient.SqlConnectionString connectionOptions, System.Data.SqlClient.SqlCredential credential, string newPassword, System.Security.SecureString newSecurePassword, bool redirectedUserInstance) (Unknown Source:0)
System.Data.SqlClient.dll!System.Data.SqlClient.SqlInternalConnectionTds.SqlInternalConnectionTds(System.Data.ProviderBase.DbConnectionPoolIdentity identity, System.Data.SqlClient.SqlConnectionString connectionOptions, System.Data.SqlClient.SqlCredential credential, object providerInfo, string newPassword, System.Security.SecureString newSecurePassword, bool redirectedUserInstance, System.Data.SqlClient.SqlConnectionString userConnectionOptions, System.Data.SqlClient.SessionData reconnectSessionData, bool applyTransientFaultHandling, string accessToken) (Unknown Source:0)
System.Data.SqlClient.dll!System.Data.SqlClient.SqlConnectionFactory.CreateConnection(System.Data.Common.DbConnectionOptions options, System.Data.Common.DbConnectionPoolKey poolKey, object poolGroupProviderInfo, System.Data.ProviderBase.DbConnectionPool pool, System.Data.Common.DbConnection owningConnection, System.Data.Common.DbConnectionOptions userOptions) (Unknown Source:0)
System.Data.SqlClient.dll!System.Data.ProviderBase.DbConnectionFactory.CreateNonPooledConnection(System.Data.Common.DbConnection owningConnection, System.Data.ProviderBase.DbConnectionPoolGroup poolGroup, System.Data.Common.DbConnectionOptions userOptions) (Unknown Source:0)
System.Data.SqlClient.dll!System.Data.ProviderBase.DbConnectionFactory.TryGetConnection(System.Data.Common.DbConnection owningConnection, System.Threading.Tasks.TaskCompletionSource retry, System.Data.Common.DbConnectionOptions userOptions, System.Data.ProviderBase.DbConnectionInternal oldConnection, out System.Data.ProviderBase.DbConnectionInternal connection) (Unknown Source:0)
System.Data.SqlClient.dll!System.Data.ProviderBase.DbConnectionInternal.TryOpenConnectionInternal(System.Data.Common.DbConnection outerConnection, System.Data.ProviderBase.DbConnectionFactory connectionFactory, System.Threading.Tasks.TaskCompletionSource retry, System.Data.Common.DbConnectionOptions userOptions) (Unknown Source:0)
System.Data.SqlClient.dll!System.Data.ProviderBase.DbConnectionClosed.TryOpenConnection(System.Data.Common.DbConnection outerConnection, System.Data.ProviderBase.DbConnectionFactory connectionFactory, System.Threading.Tasks.TaskCompletionSource retry, System.Data.Common.DbConnectionOptions userOptions) (Unknown Source:0)
System.Data.SqlClient.dll!System.Data.SqlClient.SqlConnection.TryOpen(System.Threading.Tasks.TaskCompletionSource retry) (Unknown Source:0)
System.Data.SqlClient.dll!System.Data.SqlClient.SqlConnection.Open() (Unknown Source:0)
Microsoft.Data.Tools.Schema.Sql.dll!Microsoft.Data.Tools.Schema.Common.SqlClient.ReliableSqlConnection.OpenConnection.AnonymousMethod__48_0() (Unknown Source:0)
Microsoft.Data.Tools.Schema.Sql.dll!Microsoft.Data.Tools.Schema.Common.SqlClient.RetryPolicy.ExecuteAction.AnonymousMethod__0(Microsoft.Data.Tools.Schema.Common.SqlClient.RetryState _) (Unknown Source:0)
Microsoft.Data.Tools.Schema.Sql.dll!Microsoft.Data.Tools.Schema.Common.SqlClient.RetryPolicy.ExecuteAction.AnonymousMethod__0(Microsoft.Data.Tools.Schema.Common.SqlClient.RetryState retryState) (Unknown Source:0)
Microsoft.Data.Tools.Schema.Sql.dll!Microsoft.Data.Tools.Schema.Common.SqlClient.RetryPolicy.ExecuteAction(System.Func func, System.Threading.CancellationToken? token) (Unknown Source:0)
Microsoft.Data.Tools.Schema.Sql.dll!Microsoft.Data.Tools.Schema.Common.SqlClient.RetryPolicy.ExecuteAction(System.Action action, System.Threading.CancellationToken? token) (Unknown Source:0)
Microsoft.Data.Tools.Schema.Sql.dll!Microsoft.Data.Tools.Schema.Common.SqlClient.RetryPolicy.ExecuteAction(System.Action action, System.Threading.CancellationToken? token) (Unknown Source:0)
Microsoft.Data.Tools.Schema.Sql.dll!Microsoft.Data.Tools.Schema.Common.SqlClient.ReliableSqlConnection.OpenConnection() (Unknown Source:0)
Microsoft.Data.Tools.Schema.Sql.dll!Microsoft.Data.Tools.Schema.Common.SqlClient.ReliableSqlConnection.Open() (Unknown Source:0)
Microsoft.Data.Tools.Schema.Sql.dll!Microsoft.Data.Tools.Schema.Common.SqlClient.ReliableConnectionHelper.OpenConnection(Microsoft.Data.Tools.Schema.Common.SqlClient.SqlConnectionFactory connectionFactory, bool useRetry) (Unknown Source:0)
Microsoft.Data.Tools.Schema.Sql.dll!Microsoft.Data.Tools.Schema.Sql.Deployment.SqlDeploymentPlanGenerator.OnInitialize(Microsoft.Data.Tools.Schema.Sql.Deployment.SqlDeployment engine) (Unknown Source:0)
Microsoft.Data.Tools.Schema.Sql.dll!Microsoft.Data.Tools.Schema.Sql.Deployment.SqlDeploymentPlanGenerator.Initialize(Microsoft.Data.Tools.Schema.Sql.Deployment.SqlDeployment engine) (Unknown Source:0)
Microsoft.Data.Tools.Schema.Sql.dll!Microsoft.Data.Tools.Schema.Sql.Deployment.SqlDeployment.InitializePlanGeneratator() (Unknown Source:0)
Microsoft.Data.Tools.Schema.Sql.dll!Microsoft.Data.Tools.Schema.Sql.Deployment.SqlDeployment.CreateController(System.Action msgHandler) (Unknown Source:0)
Microsoft.Data.Tools.Schema.Sql.dll!Microsoft.Data.Tools.Schema.Sql.Deployment.SqlDeployment.CreateController() (Unknown Source:0)
Microsoft.Data.Tools.Schema.Sql.dll!Microsoft.Data.Tools.Schema.Utilities.Sql.SchemaCompare.DeploymentWrapper.Compare(bool applyRefactorChanges, bool isForShowingComparisonResult) (Unknown Source:0)
Microsoft.Data.Tools.Schema.Sql.dll!Microsoft.Data.Tools.Schema.Utilities.Sql.SchemaCompare.DeploymentWrapper.CompareForComparisonResult() (Unknown Source:0)
Microsoft.Data.Tools.Schema.Sql.dll!Microsoft.Data.Tools.Schema.Utilities.Sql.SchemaCompare.DeploymentTargetComparer.Compare() (Unknown Source:0)
Microsoft.Data.Tools.Schema.Sql.dll!Microsoft.Data.Tools.Schema.Utilities.Sql.SchemaCompare.SchemaCompareController.Compare() (Unknown Source:0)
Microsoft.Data.Tools.Schema.Sql.dll!Microsoft.Data.Tools.Schema.Utilities.Sql.SchemaCompare.DataModel.SchemaCompareDataModel.Compare(System.Threading.CancellationToken token) (Unknown Source:0)
Microsoft.SqlServer.Dac.Extensions.dll!Microsoft.SqlServer.Dac.Compare.SchemaComparison.Compare(System.Threading.CancellationToken cancellationToken) (Unknown Source:0)
Microsoft.SqlServer.Dac.Extensions.dll!Microsoft.SqlServer.Dac.Compare.SchemaComparison.Compare() (Unknown Source:0)
```
## Exception

```
{System.Net.Internals.SocketExceptionFactory+ExtendedSocketException (111): Connection refused 127.0.0.1:1433
at System.Net.Sockets.Socket.DoConnect(EndPoint endPointSnapshot, SocketAddress socketAddress)}
```

Start with the C# SchemaComparison example using two local dacpac paths and inspect the call stack through SchemaComparison.Compare and the SQL deployment components. Reproduce the connection attempt to 127.0.0.1:1433, then verify that local dacpac comparisons complete without repeated SocketExceptions or several-minute delays.

Written by the indexing model from the issue text.