It's really a talent. Some dumb questions are hidden gems. Why didn't we think of that before, does it still apply now ...

I haven't got problems when upgrading to 2019. It introduces adaptive joins which may be finicky in flip-flop scenarios (large & small dataset).

Thanks for the question. Learned about hash-indexes

Looks correct. Make sure you copy the permissions

Your query is too abstracted to give much information.

If it index seeks on object8 (alias) object name, there is an index on  Object 8 Column7, Column 8 (or the other...

There isn't really much that you can do.

Are you accessing the data with OPENQUERY ( you might pass some query hints) ?

Check the linked server provider options

Is it possible to...

some of your subqueries gives more than one results. This would break the one value per row

Check if

(SELECT RS.LIB_SERVICE FROM RESSOURCE_SERVICE RS WHERE RS.CLE_REF = RIS.CLE_REFAND RS.CODE_SERVICE...

In my environment the DBA's (small environment). Have sufficients rights and know more what the patches do. Networking team can focus on the other servers

There is a stored procedure that shows if there are queries waiting for memory or cpu

sp_PressureDetector | Erik Darling Data

I don't have the Azure version, but you could capture blocking events for review with Extended-Events on Azure SQL.

It is briefly mentioned in https://docs.microsoft.com/en-us/azure/azure-sql/database/understand-resolve-blocking

Thanks Jeffrey for mentioning it.

SSRS keeps the executions of reports in the view

SELECT *

FROM [ReportServer].[dbo].[ExecutionLog3]

You could use extended events to track if the database is still in use https://www.sqlskills.com/blogs/jonathan/tracking-sql-server-database-usage/

You can review https://sqlchicken.com/2012/07/identify-and-alert-for-long-running-agent-jobs/

and https://www.mssqltips.com/sqlservertip/1523/how-to-setup-sql-server-alerts-and-email-operator-notifications/

It looks they were databases for the SSRS instance DMP2.

Do they contain dbo.Catalog, dbo.ChunckData?

You could track logins against those databases with extented events Tracking Logins with Extended Events | Voice...

1) will my SSRS 2014 reports run as is once the upgrade to SSRS 2019 has been completed or will I need to rewrite my reports?

I suppose the most reports...