He can see...

It's going to be down to estimations. Key lookups are OK on smaller row counts.

Can you post the plan?

Windows protects the roots of drives more than folders, so you're more likely to have permissions problem (which with TempDB will result in the instance not starting). Put them in...

Not so much formatted. Log files must...

https://www.simple-talk.com/content/article.aspx?article=2280

That's completely invalid syntax, bears no resemblance to an update statement, looks like an insert statement with the INSERT INTO replaced by an UPDATE SET and nothing else changed.

UPDATE ...

There's no recovery model requirements for a clustered database.

Just check and ensure that the data loss potential due to Simple Recovery is acceptable to the owners/users of the system.

That code shouldn't fail with a NULL value, or are you saying you have the string value 'NULL' present in your data?

DECLARE @DateAsString varchar(20) = NULL;

SELECT CAST(@DateAsString AS DATE)

Returns NULL,...

https://msdn.microsoft.com/en-us/library/ms187926.aspx

Stored procedures are similar to procedures in other programming languages in that they can:

Accept input parameters and return multiple values in the form of output parameters...

Correct. The availability group is at the database level. Server-level permissions are kept in master and that's not going to be part of your AG.

Just don't change any of the...

The 'create a new log file' and 'drop the old one once empty' are fine and will work. It's the ShrinkFile portion that won't, because EmptyFile only applies to data...

Create the login and user on the Primary replica. Grant the user the rights you want them to have on the secondary replica. Deny the login CONNECT rights on the...

Test and see?

CREATE TABLE #Test (

SomeValue INT

)

INSERT INTO #Test (SomeValue)

VALUES (1), (1),(1),(NULL),(NULL),(1)

PRINT 'Count'

SELECT COUNT(SomeValue) FROM #Test AS t

PRINT 'Sum'

SELECT SUM(SomeValue) FROM #Test AS t

-----------

Count

-----------

4

Warning: Null value is eliminated by...

The only thing which that process does is change the default collation for the instance (collation new databases will get by default), the collations of master and TempDB. It doesn't...

Then you need to identify the large transactions that are causing the log to grow (about the only thing that will in simple recovery) and fix that. If you can't...