diff --git a/MarkMpn.Sql4Cds.Engine.Tests/ExecutionPlanTests.cs b/MarkMpn.Sql4Cds.Engine.Tests/ExecutionPlanTests.cs
index a8dfb011..8170aae4 100644
--- a/MarkMpn.Sql4Cds.Engine.Tests/ExecutionPlanTests.cs
+++ b/MarkMpn.Sql4Cds.Engine.Tests/ExecutionPlanTests.cs
@@ -82,6 +82,8 @@ void IQueryExecutionOptions.RetrievingNextPage()
         {
         }
 
+        string IQueryExecutionOptions.PrimaryDataSource => "local";
+
         Guid IQueryExecutionOptions.UserId => Guid.NewGuid();
 
         [TestMethod]
@@ -2996,7 +2998,7 @@ public void CrossInstanceJoin()
                     TableSizeCache = new StubTableSizeCache()
                 }
             };
-            var planBuilder = new ExecutionPlanBuilder(datasources, "uat", this);
+            var planBuilder = new ExecutionPlanBuilder(datasources, this);
 
             var query = "SELECT uat.name, prod.name FROM uat.dbo.account AS uat INNER JOIN prod.dbo.account AS prod ON uat.accountid = prod.accountid WHERE uat.name <> prod.name AND uat.name LIKE '%test%'";
 
diff --git a/MarkMpn.Sql4Cds.Engine.Tests/Sql2FetchXmlTests.cs b/MarkMpn.Sql4Cds.Engine.Tests/Sql2FetchXmlTests.cs
index cc97222b..615a0db6 100644
--- a/MarkMpn.Sql4Cds.Engine.Tests/Sql2FetchXmlTests.cs
+++ b/MarkMpn.Sql4Cds.Engine.Tests/Sql2FetchXmlTests.cs
@@ -52,6 +52,8 @@ void IQueryExecutionOptions.RetrievingNextPage()
         {
         }
 
+        string IQueryExecutionOptions.PrimaryDataSource => "local";
+
         Guid IQueryExecutionOptions.UserId => Guid.NewGuid();
 
         [TestMethod]
diff --git a/MarkMpn.Sql4Cds.Engine.Tests/StubOptions.cs b/MarkMpn.Sql4Cds.Engine.Tests/StubOptions.cs
index aa814f6d..d851cd11 100644
--- a/MarkMpn.Sql4Cds.Engine.Tests/StubOptions.cs
+++ b/MarkMpn.Sql4Cds.Engine.Tests/StubOptions.cs
@@ -64,6 +64,8 @@ void IQueryExecutionOptions.RetrievingNextPage()
         {
         }
 
+        string IQueryExecutionOptions.PrimaryDataSource => "local";
+
         Guid IQueryExecutionOptions.UserId => Guid.NewGuid();
     }
 }
diff --git a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/ExpressionExtensions.cs b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/ExpressionExtensions.cs
index 925928c6..c93bfd3a 100644
--- a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/ExpressionExtensions.cs
+++ b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/ExpressionExtensions.cs
@@ -1197,9 +1197,9 @@ private static SqlDateTime GetCurrentTimestamp(IQueryExecutionOptions options)
                 return new SqlDateTime(DateTime.UtcNow);
         }
 
-        private static SqlGuid GetCurrentUser(IQueryExecutionOptions options)
+        private static SqlEntityReference GetCurrentUser(IQueryExecutionOptions options)
         {
-            return options.UserId;
+            return new SqlEntityReference(options.PrimaryDataSource, "systemuser", options.UserId);
         }
 
         /// <summary>
diff --git a/MarkMpn.Sql4Cds.Engine/ExecutionPlanBuilder.cs b/MarkMpn.Sql4Cds.Engine/ExecutionPlanBuilder.cs
index 5eaa9304..dade75df 100644
--- a/MarkMpn.Sql4Cds.Engine/ExecutionPlanBuilder.cs
+++ b/MarkMpn.Sql4Cds.Engine/ExecutionPlanBuilder.cs
@@ -21,14 +21,13 @@ public class ExecutionPlanBuilder
         private int _colNameCounter;
 
         public ExecutionPlanBuilder(IAttributeMetadataCache metadata, ITableSizeCache tableSize, IQueryExecutionOptions options)
-            : this(new[] { new DataSource { Name = "local", Metadata = metadata, TableSizeCache = tableSize } }, "local", options)
+            : this(new[] { new DataSource { Name = "local", Metadata = metadata, TableSizeCache = tableSize } }, options)
         {
         }
 
-        public ExecutionPlanBuilder(IEnumerable<DataSource> dataSources, string primaryDataSource, IQueryExecutionOptions options)
+        public ExecutionPlanBuilder(IEnumerable<DataSource> dataSources, IQueryExecutionOptions options)
         {
             DataSources = dataSources.ToDictionary(ds => ds.Name, StringComparer.OrdinalIgnoreCase);
-            PrimaryDataSource = primaryDataSource;
             Options = options;
         }
 
@@ -37,11 +36,6 @@ public ExecutionPlanBuilder(IEnumerable<DataSource> dataSources, string primaryD
         /// </summary>
         public IDictionary<string, DataSource> DataSources { get; }
 
-        /// <summary>
-        /// The name of the connection that will be used by default
-        /// </summary>
-        public string PrimaryDataSource { get; set; }
-
         /// <summary>
         /// Returns or sets a value indicating if SQL will be parsed using quoted identifiers
         /// </summary>
@@ -212,7 +206,7 @@ private ExecuteAsNode ConvertExecuteAsStatement(ExecuteAsStatement impersonate)
             {
                 UserIdSource = "systemuser.systemuserid",
                 Source = source,
-                DataSource = PrimaryDataSource
+                DataSource = Options.PrimaryDataSource
             };
         }
 
@@ -220,7 +214,7 @@ private RevertNode ConvertRevertStatement(RevertStatement revert)
         {
             return new RevertNode
             {
-                DataSource = PrimaryDataSource
+                DataSource = Options.PrimaryDataSource
             };
         }
 
@@ -301,7 +295,7 @@ private IExecutionPlanNode ConvertInsertSelectSource(SelectInsertSource selectSo
 
         private DataSource SelectDataSource(SchemaObjectName schemaObject)
         {
-            var databaseName = schemaObject.DatabaseIdentifier?.Value ?? PrimaryDataSource;
+            var databaseName = schemaObject.DatabaseIdentifier?.Value ?? Options.PrimaryDataSource;
             
             if (!DataSources.TryGetValue(databaseName, out var dataSource))
                 throw new NotSupportedQueryFragmentException("Invalid database name", schemaObject) { Suggestion = $"Available database names:\r\n* {String.Join("\r\n*", DataSources.Keys.OrderBy(k => k))}" };
@@ -526,7 +520,7 @@ private DeleteNode ConvertDeleteStatement(DeleteSpecification delete, IList<Opti
                 TopRowFilter = delete.TopRowFilter
             };
 
-            var deleteTarget = new UpdateTargetVisitor(target.SchemaObject, PrimaryDataSource);
+            var deleteTarget = new UpdateTargetVisitor(target.SchemaObject, Options.PrimaryDataSource);
             queryExpression.FromClause.Accept(deleteTarget);
 
             if (String.IsNullOrEmpty(deleteTarget.TargetEntityName))
@@ -680,7 +674,7 @@ private UpdateNode ConvertUpdateStatement(UpdateSpecification update, IList<Opti
                 TopRowFilter = update.TopRowFilter
             };
 
-            var updateTarget = new UpdateTargetVisitor(target.SchemaObject, PrimaryDataSource);
+            var updateTarget = new UpdateTargetVisitor(target.SchemaObject, Options.PrimaryDataSource);
             queryExpression.FromClause.Accept(updateTarget);
 
             if (String.IsNullOrEmpty(updateTarget.TargetEntityName))
@@ -940,7 +934,7 @@ private IRootExecutionPlanNode ConvertSelectStatement(SelectStatement select)
             if (Options.UseTDSEndpoint && TDSEndpointAvailable)
             {
                 select.ScriptTokenStream = null;
-                return new SqlNode { DataSource = PrimaryDataSource, Sql = select.ToSql() };
+                return new SqlNode { DataSource = Options.PrimaryDataSource, Sql = select.ToSql() };
             }
 
             if (select.ComputeClauses != null && select.ComputeClauses.Count > 0)
diff --git a/MarkMpn.Sql4Cds.Engine/ExpressionFunctions.cs b/MarkMpn.Sql4Cds.Engine/ExpressionFunctions.cs
index bb14145d..7396ae77 100644
--- a/MarkMpn.Sql4Cds.Engine/ExpressionFunctions.cs
+++ b/MarkMpn.Sql4Cds.Engine/ExpressionFunctions.cs
@@ -385,9 +385,9 @@ public static SqlInt32 CharIndex(SqlString find, SqlString search, SqlInt32 star
         /// </summary>
         /// <param name="options">The options that provide access to the user details</param>
         /// <returns></returns>
-        public static SqlGuid User_Name(IQueryExecutionOptions options)
+        public static SqlEntityReference User_Name(IQueryExecutionOptions options)
         {
-            return options.UserId;
+            return new SqlEntityReference(options.PrimaryDataSource, "systemuser", options.UserId);
         }
 
         /// <summary>
diff --git a/MarkMpn.Sql4Cds.Engine/IQueryExecutionOptions.cs b/MarkMpn.Sql4Cds.Engine/IQueryExecutionOptions.cs
index c67d95c7..1e1086cf 100644
--- a/MarkMpn.Sql4Cds.Engine/IQueryExecutionOptions.cs
+++ b/MarkMpn.Sql4Cds.Engine/IQueryExecutionOptions.cs
@@ -118,6 +118,11 @@ public interface IQueryExecutionOptions
         /// </summary>
         void RetrievingNextPage();
 
+        /// <summary>
+        /// Returns the name of the primary data source the query is being executed in
+        /// </summary>
+        string PrimaryDataSource { get; }
+
         /// <summary>
         /// Returns the unique identifier of the current user
         /// </summary>
diff --git a/MarkMpn.Sql4Cds.Engine/Sql2FetchXml.cs b/MarkMpn.Sql4Cds.Engine/Sql2FetchXml.cs
index 60ce3bfe..b7660815 100644
--- a/MarkMpn.Sql4Cds.Engine/Sql2FetchXml.cs
+++ b/MarkMpn.Sql4Cds.Engine/Sql2FetchXml.cs
@@ -59,6 +59,8 @@ public QueryExecutionOptions(Sql2FetchXml sql2FetchXml)
 
             public bool UseLocalTimeZone => false;
 
+            public string PrimaryDataSource => "local";
+
             public Guid UserId { get; set; }
 
             public List<JoinOperator> JoinOperatorsAvailable => new List<JoinOperator> { JoinOperator.Inner, JoinOperator.LeftOuter };
diff --git a/MarkMpn.Sql4Cds/QueryExecutionOptions.cs b/MarkMpn.Sql4Cds/QueryExecutionOptions.cs
index b80b2644..d72b54d9 100644
--- a/MarkMpn.Sql4Cds/QueryExecutionOptions.cs
+++ b/MarkMpn.Sql4Cds/QueryExecutionOptions.cs
@@ -174,6 +174,8 @@ public void RetrievingNextPage()
                 throw new QueryExecutionException($"Hit maximum retrieval limit. This limit is in place to protect against excessive API requests. Try restricting the data to retrieve with WHERE clauses or eliminating subqueries.\r\nYour limit of {Settings.Instance.MaxRetrievesPerQuery:N0} retrievals per query can be modified in Settings.");
         }
 
+        public string PrimaryDataSource => _con.ConnectionName;
+
         public Guid UserId
         {
             get
diff --git a/MarkMpn.Sql4Cds/SqlQueryControl.cs b/MarkMpn.Sql4Cds/SqlQueryControl.cs
index f9d83d1e..fefcb906 100644
--- a/MarkMpn.Sql4Cds/SqlQueryControl.cs
+++ b/MarkMpn.Sql4Cds/SqlQueryControl.cs
@@ -854,7 +854,7 @@ private void backgroundWorker_DoWork(object sender, DoWorkEventArgs e)
             backgroundWorker.ReportProgress(0, "Executing query...");
 
             var options = new QueryExecutionOptions(_con, DataSources[_con.ConnectionName].Connection, backgroundWorker, this);
-            var converter = new ExecutionPlanBuilder(DataSources.Values, _con.ConnectionName, options);
+            var converter = new ExecutionPlanBuilder(DataSources.Values, options);
 
             if (Settings.Instance.UseTSQLEndpoint &&
                 args.Execute &&