Well, there's nothing inherent in SQL Server that would result in the system running slower just because of the time passed. You've already hit on what is usually the biggest...

Absolutely beguiling. I think everyone knows it so well because we've all been bitten by it at one point or another.

Jacek Falkiewicz (10/20/2014)

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Grant Fritchey (10/19/2014)

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Contention for resources? Not sure without more information. Have you looked at the blocks and wait resources of the process while it's running? That's where I'd...

In addition to the OR, we're doing NOT EQUALS. Between the two you're pretty much guaranteed scans on your indexes.

If you need to capture events per database, you can set up a filter in extended events. In fact, it's filtering mechanism is the one gigantic improvement over trace events...

Eirikur Eiriksson (10/19/2014)

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On the contrary, it is very useful as it respects the left outer join, which in essence return all records from the right hand side and only those...

Probably not, since everything changed. You might want to modify that process too.

So you mean a foreign key constraint that allows nulls versus one that does not? Yes, changing to not allowing null values could be more difficult because you'll have to...

First is the LEFT JOIN as described above, but second, compound primary keys. The JOIN criteria could simply require multiple columns. I've seen lots and lots of uses for multiple...

Contention for resources? Not sure without more information. Have you looked at the blocks and wait resources of the process while it's running? That's where I'd start in order to...

Sounds useful to me. I worked for an insurance company where we had to maintain our data in just such a manner with differing versions of data with differing effective...

OR can lead to scans on the index because multiple levels of testing are needed and you can't simply seek for values because of that. Depending on the use of...

A case statement in the SELECT list that just picks a value based on simple input shouldn't negatively impact performance. It's when you start putting all sorts of additional data...

Yeah, you nailed it. The extra bites are in the balanced tree of the index. But your napkin calculation should be fine for most purposes.

You might want to look at SQL Compare by Red Gate Software. It can compare objects between two databases, between scripts and a database, backup and a database or source...