It took me more than half hour to figure out how to start an XEvents trace on a read-scale out instance of Azure SQL Managed Instance. It’s hard to monitor read scale-out instances, so tracing is desirable! I started with a simple trace of sql_statement_completed. Hopefully this saves other folks some time.
If you use readable secondaries in Availability Groups or Read-Scale out instances in Azure SQL Managed Instance, you may have queries fail repeatedly if there is a glitch and statistics are not successfully ‘refreshed’ on the secondary replica. Those queries may keep failing until you manually intervene.
It’s unclear if Microsoft will ever fix this. There is a well established support deflection article which documents the issue and provides ‘workarounds’.
This morning, I received the following question from a user:
Could you please clarify SQLServer “Data Row” size: If I run the script below on SQL Server 2012, then Slot(row) Size is 710 bytes if I run the same script against SQL Server 2016 and above, then Slot(row) Size is 724 bytes.
They then provided a script which creates and inserts a few rows into a sample table, runs the DBCC IND command to find a list of pages for the sample table, then uses the DBCC PAGE command to examine the page.
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