An observant person has probably noticed that SQL queries requiring disk reads not only have longer duration but also higher CPU times. It is not hard then to deduce that disk access (for both HDD and SSD), which involves the OS performing an IO call, the SQL Server process finding a place in the buffer cache for the data pages, and possibly ...

Has any one encountered SQL backup failures that were ultimately diagnosed to a MemToLeave issue? This should only occur on 32-bit SQL Server versions, including 2000 and 2005. A number of other operations could generate a MemToLeave issue, but I am only addressing backup failures here. (the diagnosis should have led to messages in the SQL Logs ...

  Last December, I announced that my SQL Server Internals course was being made into a DVD series, and I then had several follow up posts over the next few months. I flew to NY 3 times, and have filmed 3 lessons. I was waiting to film the 4th, for which I already have the slides and the scripts, until the 2nd one was released, or at least ...

I asked for some names of people who you would like to see interviewed and Craig Freedman's name popped up a couple of times. I contacted Craig and he was kind enough to take time out from his busy schedule to answer these questions.  So, here are the questions. What are the most important things a person can do to master SQL ...

I find that auto_update statistics in SQL Server is a really good thing.  Without it, many third-party applications would simply fall over from lack of preventative maintenance.  With it, they are able to run for extraordinarily long periods of time without really needing a full-time DBA to check up on the databases.   Having said ...

You might encounter a situation, under a very heavy workload, where processing for certain transactions starts out very efficiently, but over time becomes much less efficient.    A good place to start troubleshooting is, of course, PerfMon.  But PerfMon can fail to reveal the culprit, since the CPU can remain stable and moderate ...

I almost titled this one with OT, but then I realized that this MY BLOG, and nothing is really off-topic, right? It's my blog and I can say whatever I want. :-) I get a real big kick out of seeing places in movies where I have actually been. I took my husband to NYC for his birthday in early March, and the first night, in our hotel room, the ...

If you’ve ever taken the time to read http://www.tpc.org/results/FDR/TPCC/hp_orca1tb_win64_fdr.pdf, you might find a bit in there that’s confusing.   ''Microsoft SQL Server 2005 Enterprise Edition 64-bit Service Pack 1 was configured to utilize ''soft NUMA'', a feature that allows network connections to be affined to specific groups of CPUs ...

You'd think an article called ''NASTY RUMORS ABOUT MAXDOP'' would have something to do with Britney Spears or maybe Robert Downy Jr, but in that case it'd be total fiction (at least, it would be coming from my pen).   So, I was en route to the 2008 Microsoft MVP Summit yesterday and I had a chance to catch up on my reading.  You ...

Here is a question I just received from the feedback page on my web site: I have finished the book <the storage engine> and like it very much. I am now reading <query tuning and optimization> I know in the READ COMMITTED SNAPSHOT isolation, when a row is being modified in a transaction, it generates an old committed version so ...