Literally nothing to go on.

Where are you running backup commands from?

Look there to see what the connection settings are, etc. If necessary, fire up an Extended Events session and watch...

Nope.

A restoring database is in the process of moving all the data pages and then recovering any transactions. They just can't be accessed. At all.

To solve this, I'd look outside...

Same answer as on 2012. The CU, cumulative update, is what it says, cumulative. Any other patches are individual.

The security updates are not cumulative, so yeah, you'd need to install them separately. BTW, according to this site, there are three, not two for 2012 SP4.

Hard to say without details.

It depends.

It could be that you simply have queries running against the table that are filtering on columns where a non-clustered index could help. But, it...

Just remember, the first column is the column used to create the histogram in statistics. The histogram is one of the leading drivers for the optimizer to make determinations on...

The only way you can tell this is if you have a monitoring system set up. Either one you build yourself using Perfmon counters, or a 3rd party tool. There's...

Personally, I'd got the third party route. It's going to be a lot easier. However, yeah, there are tools. First, get PerfMon. Capture the appropriate counters there. You can program...

It's completely dependent on the indexes. I know Minion lets you pick lists of indexes & break up the process. I suppose Ola's script must too. Do that. Do the...

There's a lot to unpack here, but I'll try to answer some of it.

First question, can you identify which tables have been changed between two dates? Yes. The key to...

It's a parallelism deadlock. So, whichever query was involved, it was the only query involved. If you can't see the query from Profiler, you're stuck. Profiler doesn't have a correlation...

1. Generally, yes. If the index is in active use, it's probably needed.
2. The rule I follow is pretty simple. Unless I can absolutely prove otherwise, through very thorough testing,...

I appreciate all the feedback. No arguments from me on any of it. This all really is a balancing act. Getting it to "just right" is hard.

Each restart, yes, but also failovers, detach/attach, all sorts of variation on that data. It is the one place to try to determine if indexes are in use, but, it's...

The best way to get detailed information about the behavior of SQL Server is through the use of Extended Events. They are not zero cost, but they are the...