I just realized that our two SQL Server on VMwaresessions that I co-presented on Tuesday at VMworld USA, both of which made the top 10 sessions of the day list at the conference, are now on YouTube! They are free to watch for everyone! For those of you with virtualized SQL Servers, regardless of platform and cloud or…
Tag: Performance
VMworld EMEA SQL Server Sessions
This trip to Barcelona for the next VMworld EMEA conference next week will be my second trip to this conference in two years. I’m ecstatic to get there and start talking SQL Server content with folks! I’m presenting on SQL Server performance, scalability, and monitoring in three sessions at this conference. Tuesday 11am – Monster…
When should I add an index?
We all know indexes are good and I’m hoping everyone knows you can have too many indexes. That means we should be careful when adding new indexes right? So when should we add a new index? Here are my general rules of thumb, although of course, you should always use your best judgment. Also, this…
Using GROUP BY instead of DISTINCT
Recently, Aaron Bertrand (b/t) posted Performance Surprises and Assumptions : GROUP BY vs. DISTINCT. In it he says he prefers GROUP BY over DISTINCT. He discusses the fact that GROUP BY will, in fact, under certain circumstances, produce a faster query plan. I highly recommend taking the time to read it. In fact, if you…
Queries with optional parameters
These are those queries where you are pulling for, let’s say, a first name, a last name, a state, and/or a city. Simple enough, until you notice that or. We might only get a first name, or a state and the query still needs to work. These queries are commonly called Catch all queries Kitchen…
What Really Causes Performance Problems?
Every IT shop has its problems with performance: some localized, and some that span a server, or even multiple servers. Technologists tend to treat these problems as isolated incidents – solving one, then another, and then another. This happens especially when a problem is recurring but intermittent. When a slowdown
Too Many Indexes?
Indexes are great. They speed up our queries. In fact, without them relational database systems wouldn’t work. Different indexes work best for different queries. In a system with a lot of queries that means we could need a lot of indexes. Fortunately we can have up to 999 non-clustered indexes per table and one clustered…
Load Testing Results Might Not Be What You Think
Bottlenecks in your testing tools, infrastructure, or methodology might just hurt your load test results, and the results can skew your metrics. For example… A few weeks ago we were running an iperf load test to see what improvements (if any) could be made to the configuration of a Windows Server networking stack. Setting up iperf…
RBAR vs Batch
Many years ago Jeff Moden (of SQL Server Central fame) came up with the concept of RBAR. Row-By-Agonizing-Row. At it’s most basic it means you are inserting one row at a time. A more broad interpretation says it’s any type of loop even the type caused by a recursive CTE. And the point? Loops are…
VMware CPU Co-Stop and SQL Server Performance (continued)
A number of you sent me some excellent questions about this topic, and my favorite asked me for the query that you can use to get this information DIRECTLY from the VMware vCenter database. SO… here you go! Just plug in your VM name (which might differ from your FQDN name). Feel free to modify…