Update sql-data-warehouse-manage-monitor.md

Updated TempDB section to add a note about the hidden QTABLE database and updated the 2nd paragraph under the TempDB Query to have the correct details about TempDB sizing.
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cc: @WilliamDAssafMSFT

Author: KevinConanMSFT

articles/synapse-analytics/sql-data-warehouse/sql-data-warehouse-manage-monitor.md

@@ -212,9 +212,12 @@ WHERE DB_NAME(ssu.database_id) = 'tempdb'
 ORDER BY sr.request_id;
 ```
 
+> [!NOTE]
+> Data Movement uses a hidden database called QTABLE.  When that database is filled, the query will also return an error message about tempdb being out of space.  Details about QTABLE are not returned in the above query.
+
 If you have a query that is consuming a large amount of memory or have received an error message related to the allocation of tempdb, it could be due to a very large [CREATE TABLE AS SELECT (CTAS)](/sql/t-sql/statements/create-table-as-select-azure-sql-data-warehouse) or [INSERT SELECT](/sql/t-sql/statements/insert-transact-sql?toc=/azure/synapse-analytics/sql-data-warehouse/toc.json&bc=/azure/synapse-analytics/sql-data-warehouse/breadcrumb/toc.json&view=azure-sqldw-latest&preserve-view=true) statement running that is failing in the final data movement operation. This can usually be identified as a ShuffleMove operation in the distributed query plan right before the final INSERT SELECT.  Use [sys.dm_pdw_request_steps](/sql/relational-databases/system-dynamic-management-views/sys-dm-pdw-request-steps-transact-sql?toc=/azure/synapse-analytics/sql-data-warehouse/toc.json&bc=/azure/synapse-analytics/sql-data-warehouse/breadcrumb/toc.json&view=azure-sqldw-latest&preserve-view=true) to monitor ShuffleMove operations.
 
-The most common mitigation is to break your CTAS or INSERT SELECT statement into multiple load statements so the data volume will not exceed the 2TB per node tempdb limit (when at or above DW500c). You can also scale your cluster to a larger size which will spread the tempdb size across more nodes reducing the tempdb on each individual node.
+The most common mitigation is to break your CTAS or INSERT SELECT statement into multiple load statements so the data volume will not exceed the 399GB per 100DWUc tempdb limit. You can also scale your cluster to a larger size to increase how much tempdb space you have.
 
 In addition to CTAS and INSERT SELECT statements, large, complex queries running with insufficient memory can spill into tempdb causing queries to fail.  Consider running with a larger [resource class](resource-classes-for-workload-management.md) to avoid spilling into tempdb.