Optimizations to SQL queue length provider (#4327)

* dont query star (#4317)

* avoid array alloc in sql UpdateChunk (#4318)

---------

Co-authored-by: Simon Cropp <simon.cropp@gmail.com>

src/ServiceControl.Transports.SqlServer/QueueLengthProvider.cs

@@ -99,7 +99,7 @@ async Task QueryTableSizes(CancellationToken cancellationToken)
 
         async Task UpdateChunk(SqlConnection connection, KeyValuePair<SqlTable, int>[] chunk, CancellationToken cancellationToken)
         {
-            var query = string.Join(Environment.NewLine, chunk.Select(c => BuildQueueLengthQuery(c.Key)).ToArray());
+            var query = string.Join(Environment.NewLine, chunk.Select(c => BuildQueueLengthQuery(c.Key)));
 
             await using var command = new SqlCommand(query, connection);
             await using var reader = await command.ExecuteReaderAsync(cancellationToken);
@@ -132,16 +132,20 @@ static string BuildQueueLengthQuery(SqlTable t)
             //      Min and Max values return NULL when no rows are found.
             if (t.QuotedCatalog == null)
             {
-                return $@"IF (EXISTS (SELECT *  FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = '{t.UnquotedSchema}' AND  TABLE_NAME = '{t.UnquotedName}'))
-                            SELECT isnull(cast(max([RowVersion]) - min([RowVersion]) + 1 AS int), 0) FROM {t.QuotedSchema}.{t.QuotedName} WITH (nolock)
-                          ELSE
-                            SELECT -1;";
+                return $"""
+                        IF (EXISTS (SELECT TABLE_NAME FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = '{t.UnquotedSchema}' AND TABLE_NAME = '{t.UnquotedName}'))
+                          SELECT isnull(cast(max([RowVersion]) - min([RowVersion]) + 1 AS int), 0) FROM {t.QuotedSchema}.{t.QuotedName} WITH (nolock)
+                        ELSE
+                          SELECT -1;
+                        """;
             }
 
-            return $@"IF (EXISTS (SELECT *  FROM {t.QuotedCatalog}.INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = '{t.UnquotedSchema}' AND  TABLE_NAME = '{t.UnquotedName}'))
-                        SELECT isnull(cast(max([RowVersion]) - min([RowVersion]) + 1 AS int), 0) FROM {t.QuotedCatalog}.{t.QuotedSchema}.{t.QuotedName} WITH (nolock)
-                      ELSE
-                        SELECT -1;";
+            return $"""
+                    IF (EXISTS (SELECT TABLE_NAME FROM {t.QuotedCatalog}.INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = '{t.UnquotedSchema}' AND TABLE_NAME = '{t.UnquotedName}'))
+                      SELECT isnull(cast(max([RowVersion]) - min([RowVersion]) + 1 AS int), 0) FROM {t.QuotedCatalog}.{t.QuotedSchema}.{t.QuotedName} WITH (nolock)
+                    ELSE
+                      SELECT -1;
+                    """;
         }
 
         readonly ConcurrentDictionary<EndpointToQueueMapping, SqlTable> tableNames = new ConcurrentDictionary<EndpointToQueueMapping, SqlTable>();