Performance Regression After Upgrading from SQL Server 2016 to 2022

• abdalah.mehdoini

  Ten Centuries

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  September 8, 2026 at 11:50 am

  #4981962

  Hello everyone,

  Last week we performed an upgrade of our SQL Server instance, moving from SQL Server 2016 to SQL Server 2022. At first everything went smoothly, and we set the database compatibility level to 160 as recommended.

  However, shortly after the upgrade we started receiving complaints about significant performance degradation on the instance. Stored procedures that normally run in a few seconds suddenly started taking hours, sometimes without completing at all.

  When checking the Query Store, I noticed that several execution plans had switched from batch mode to row mode, especially on index seek operations. In batch mode, SQL Server suggested index recommendations, which I applied.

  But after adding the recommended indexes, I observed new regressions on other queries, with the same pattern repeating:

  the query switches to batch mode

  SQL Server recommends adding another index

  after adding it, another regression appears elsewhere

  It feels like I’m stuck in an endless loop of index recommendations, where each fix triggers a new regression on a different query.

  Has anyone experienced this kind of behavior after upgrading to SQL Server 2022? Any insights or feedback would be greatly appreciated.

  Thanks in advance.