Rename worker table to leases table (Azure#319)

Author: JatinSanghvi

README.md

@@ -605,9 +605,9 @@ The trigger binding utilizes SQL [change tracking](https://docs.microsoft.com/sq
     ENABLE CHANGE_TRACKING;
     ```
 
-    For more information, please refer to the documentation [here](https://docs.microsoft.com/sql/relational-databases/track-changes/enable-and-disable-change-tracking-sql-server#enable-change-tracking-for-a-table). The trigger needs to have read access on the table being monitored for changes as well as to the change tracking system tables. It also needs write access to an `az_func` schema within the database, where it will create additional worker tables to store the trigger states and leases. Each function trigger will thus have an associated change tracking table and worker table.
+    For more information, please refer to the documentation [here](https://docs.microsoft.com/sql/relational-databases/track-changes/enable-and-disable-change-tracking-sql-server#enable-change-tracking-for-a-table). The trigger needs to have read access on the table being monitored for changes as well as to the change tracking system tables. It also needs write access to an `az_func` schema within the database, where it will create additional leases tables to store the trigger states and leases. Each function trigger will thus have an associated change tracking table and leases table.
 
-    > **NOTE:** The worker table contains all columns corresponding to the primary key from the user table and three additional columns named `_az_func_ChangeVersion`, `_az_func_AttemptCount` and `_az_func_LeastExpirationTime`. If any of the primary key columns happen to have the same name, that will result in an error message listing any conflicts. In this case, the listed primary key columns must be renamed for the trigger to work.
+    > **NOTE:** The leases table contains all columns corresponding to the primary key from the user table and three additional columns named `_az_func_ChangeVersion`, `_az_func_AttemptCount` and `_az_func_LeastExpirationTime`. If any of the primary key columns happen to have the same name, that will result in an error message listing any conflicts. In this case, the listed primary key columns must be renamed for the trigger to work.
 
 #### Trigger Samples
 The trigger binding takes two [arguments](https://github.com/Azure/azure-functions-sql-extension/blob/main/src/TriggerBinding/SqlTriggerAttribute.cs)

src/Telemetry/Telemetry.cs

@@ -359,11 +359,11 @@ public enum TelemetryPropertyName
         ErrorName,
         ExceptionType,
         HasIdentityColumn,
+        LeasesTableName,
         QueryType,
         ServerVersion,
         Type,
         UserFunctionId,
-        WorkerTableName,
     }
 
     /// <summary>
@@ -376,7 +376,7 @@ public enum TelemetryMeasureName
         CommandDurationMs,
         CreatedSchemaDurationMs,
         CreateGlobalStateTableDurationMs,
-        CreateWorkerTableDurationMs,
+        CreateLeasesTableDurationMs,
         DurationMs,
         GetCaseSensitivityDurationMs,
         GetChangesDurationMs,

src/TriggerBinding/SqlTableChangeMonitor.cs

@@ -9,10 +9,10 @@ internal static class SqlTriggerConstants
 
         public const string GlobalStateTableName = "[" + SchemaName + "].[GlobalState]";
 
-        public const string WorkerTableNameFormat = "[" + SchemaName + "].[Worker_{0}]";
+        public const string LeasesTableNameFormat = "[" + SchemaName + "].[Leases_{0}]";
 
-        public const string WorkerTableChangeVersionColumnName = "_az_func_ChangeVersion";
-        public const string WorkerTableAttemptCountColumnName = "_az_func_AttemptCount";
-        public const string WorkerTableLeaseExpirationTimeColumnName = "_az_func_LeaseExpirationTime";
+        public const string LeasesTableChangeVersionColumnName = "_az_func_ChangeVersion";
+        public const string LeasesTableAttemptCountColumnName = "_az_func_AttemptCount";
+        public const string LeasesTableLeaseExpirationTimeColumnName = "_az_func_LeaseExpirationTime";
     }
 }

src/TriggerBinding/SqlTriggerConstants.cs

@@ -103,19 +103,19 @@ public async Task StartAsync(CancellationToken cancellationToken)
                     IReadOnlyList<(string name, string type)> primaryKeyColumns = await this.GetPrimaryKeyColumnsAsync(connection, userTableId, cancellationToken);
                     IReadOnlyList<string> userTableColumns = await this.GetUserTableColumnsAsync(connection, userTableId, cancellationToken);
 
-                    string workerTableName = string.Format(CultureInfo.InvariantCulture, SqlTriggerConstants.WorkerTableNameFormat, $"{this._userFunctionId}_{userTableId}");
-                    this._logger.LogDebug($"Worker table name: '{workerTableName}'.");
-                    this._telemetryProps[TelemetryPropertyName.WorkerTableName] = workerTableName;
+                    string leasesTableName = string.Format(CultureInfo.InvariantCulture, SqlTriggerConstants.LeasesTableNameFormat, $"{this._userFunctionId}_{userTableId}");
+                    this._logger.LogDebug($"leases table name: '{leasesTableName}'.");
+                    this._telemetryProps[TelemetryPropertyName.LeasesTableName] = leasesTableName;
 
                     var transactionSw = Stopwatch.StartNew();
-                    long createdSchemaDurationMs = 0L, createGlobalStateTableDurationMs = 0L, insertGlobalStateTableRowDurationMs = 0L, createWorkerTableDurationMs = 0L;
+                    long createdSchemaDurationMs = 0L, createGlobalStateTableDurationMs = 0L, insertGlobalStateTableRowDurationMs = 0L, createLeasesTableDurationMs = 0L;
 
                     using (SqlTransaction transaction = connection.BeginTransaction(System.Data.IsolationLevel.RepeatableRead))
                     {
                         createdSchemaDurationMs = await CreateSchemaAsync(connection, transaction, cancellationToken);
                         createGlobalStateTableDurationMs = await CreateGlobalStateTableAsync(connection, transaction, cancellationToken);
                         insertGlobalStateTableRowDurationMs = await this.InsertGlobalStateTableRowAsync(connection, transaction, userTableId, cancellationToken);
-                        createWorkerTableDurationMs = await CreateWorkerTableAsync(connection, transaction, workerTableName, primaryKeyColumns, cancellationToken);
+                        createLeasesTableDurationMs = await CreateLeasesTableAsync(connection, transaction, leasesTableName, primaryKeyColumns, cancellationToken);
                         transaction.Commit();
                     }
 
@@ -127,7 +127,7 @@ public async Task StartAsync(CancellationToken cancellationToken)
                         userTableId,
                         this._userTable,
                         this._userFunctionId,
-                        workerTableName,
+                        leasesTableName,
                         userTableColumns,
                         primaryKeyColumns.Select(col => col.name).ToList(),
                         this._executor,
@@ -142,7 +142,7 @@ public async Task StartAsync(CancellationToken cancellationToken)
                         [TelemetryMeasureName.CreatedSchemaDurationMs] = createdSchemaDurationMs,
                         [TelemetryMeasureName.CreateGlobalStateTableDurationMs] = createGlobalStateTableDurationMs,
                         [TelemetryMeasureName.InsertGlobalStateTableRowDurationMs] = insertGlobalStateTableRowDurationMs,
-                        [TelemetryMeasureName.CreateWorkerTableDurationMs] = createWorkerTableDurationMs,
+                        [TelemetryMeasureName.CreateLeasesTableDurationMs] = createLeasesTableDurationMs,
                         [TelemetryMeasureName.TransactionDurationMs] = transactionSw.ElapsedMilliseconds,
                     };
 
@@ -213,7 +213,7 @@ private async Task<int> GetUserTableIdAsync(SqlConnection connection, Cancellati
         /// Gets the names and types of primary key columns of the user table.
         /// </summary>
         /// <exception cref="InvalidOperationException">
-        /// Thrown if there are no primary key columns present in the user table or if their names conflict with columns in worker table.
+        /// Thrown if there are no primary key columns present in the user table or if their names conflict with columns in leases table.
         /// </exception>
         private async Task<IReadOnlyList<(string name, string type)>> GetPrimaryKeyColumnsAsync(SqlConnection connection, int userTableId, CancellationToken cancellationToken)
         {
@@ -263,9 +263,9 @@ FROM sys.indexes AS i
 
                 string[] reservedColumnNames = new[]
                 {
-                    SqlTriggerConstants.WorkerTableChangeVersionColumnName,
-                    SqlTriggerConstants.WorkerTableAttemptCountColumnName,
-                    SqlTriggerConstants.WorkerTableLeaseExpirationTimeColumnName
+                    SqlTriggerConstants.LeasesTableChangeVersionColumnName,
+                    SqlTriggerConstants.LeasesTableAttemptCountColumnName,
+                    SqlTriggerConstants.LeasesTableLeaseExpirationTimeColumnName
                 };
 
                 var conflictingColumnNames = primaryKeyColumns.Select(col => col.name).Intersect(reservedColumnNames).ToList();
@@ -326,7 +326,7 @@ FROM sys.columns AS c
         }
 
         /// <summary>
-        /// Creates the schema for global state table and worker tables, if it does not already exist.
+        /// Creates the schema for global state table and leases tables, if it does not already exist.
         /// </summary>
         private static async Task<long> CreateSchemaAsync(SqlConnection connection, SqlTransaction transaction, CancellationToken cancellationToken)
         {
@@ -409,33 +409,33 @@ INSERT INTO {SqlTriggerConstants.GlobalStateTableName}
         }
 
         /// <summary>
-        /// Creates the worker table for the 'user function and table', if one does not already exist.
+        /// Creates the leases table for the 'user function and table', if one does not already exist.
         /// </summary>
-        private static async Task<long> CreateWorkerTableAsync(
+        private static async Task<long> CreateLeasesTableAsync(
             SqlConnection connection,
             SqlTransaction transaction,
-            string workerTableName,
+            string leasesTableName,
             IReadOnlyList<(string name, string type)> primaryKeyColumns,
             CancellationToken cancellationToken)
         {
             string primaryKeysWithTypes = string.Join(", ", primaryKeyColumns.Select(col => $"{col.name.AsBracketQuotedString()} {col.type}"));
             string primaryKeys = string.Join(", ", primaryKeyColumns.Select(col => col.name.AsBracketQuotedString()));
 
-            string createWorkerTableQuery = $@"
-                IF OBJECT_ID(N'{workerTableName}', 'U') IS NULL
-                    CREATE TABLE {workerTableName} (
+            string createLeasesTableQuery = $@"
+                IF OBJECT_ID(N'{leasesTableName}', 'U') IS NULL
+                    CREATE TABLE {leasesTableName} (
                         {primaryKeysWithTypes},
-                        {SqlTriggerConstants.WorkerTableChangeVersionColumnName} bigint NOT NULL,
-                        {SqlTriggerConstants.WorkerTableAttemptCountColumnName} int NOT NULL,
-                        {SqlTriggerConstants.WorkerTableLeaseExpirationTimeColumnName} datetime2,
+                        {SqlTriggerConstants.LeasesTableChangeVersionColumnName} bigint NOT NULL,
+                        {SqlTriggerConstants.LeasesTableAttemptCountColumnName} int NOT NULL,
+                        {SqlTriggerConstants.LeasesTableLeaseExpirationTimeColumnName} datetime2,
                         PRIMARY KEY ({primaryKeys})
                     );
             ";
 
-            using (var createWorkerTableCommand = new SqlCommand(createWorkerTableQuery, connection, transaction))
+            using (var createLeasesTableCommand = new SqlCommand(createLeasesTableQuery, connection, transaction))
             {
                 var stopwatch = Stopwatch.StartNew();
-                await createWorkerTableCommand.ExecuteNonQueryAsync(cancellationToken);
+                await createLeasesTableCommand.ExecuteNonQueryAsync(cancellationToken);
                 return stopwatch.ElapsedMilliseconds;
             }
         }

src/TriggerBinding/SqlTriggerListener.cs

@@ -123,7 +123,7 @@ public void PrimaryKeyNotCreatedTriggerTest()
 
         /// <summary>
         /// Tests the error message when the user table contains one or more primary keys with names conflicting with
-        /// column names in the worker table.
+        /// column names in the leases table.
         /// </summary>
         [Fact]
         public void ReservedPrimaryKeyColumnNamesTriggerTest()

test/Integration/SqlTriggerBindingIntegrationTests.cs

@@ -11,7 +11,7 @@ public static class ReservedPrimaryKeyColumnNamesTrigger
     {
         /// <summary>
         /// Used in verification of the error message when the user table contains one or more primary keys with names
-        /// conflicting with column names in the worker table.
+        /// conflicting with column names in the leases table.
         /// </summary>
         [FunctionName(nameof(ReservedPrimaryKeyColumnNamesTrigger))]
         public static void Run(