THIS IS NOT AN APRIL FOOL POST! Seriously. My Speaker of the Month for April 2016 is Keith Tate (b|t) and his session at SQL Saturday Chicago called Profiler is Dead, Long Live Extended Events. I actually suspected very strongly from the start of the session that it was going to be good. The reason for this, Keith was having issues with his machine, but he started the session anyway. It was an excellent beginning. Then, he started to talk about Extended Events and use his slide deck to emphasize the points he was making, and it was wonderful. For example, as he talked about the way the number of events has grown in each version of SQL Server since 2008, he used larger and larger fonts with the bigger…
One of the many advantages of SQL Cruise is the ability to have enough time during a presentation to be able to answer questions from the people there in great detail. One question came up while I was showing the new functionality of Query Store (available soon in SQL Server 2016, available right now in Azure SQL Database). What happens to plan forcing when you have OPTION RECOMPILE on a query? Great question. I have a favorite procedure I use to illustrate the functionality of parameter sniffing: ALTER PROC dbo.AddressByCity @City NVARCHAR(30) AS SELECT a.AddressID, a.AddressLine1, a.AddressLine2, a.City, sp.Name AS StateProvinceName, a.PostalCode FROM Person.Address AS a JOIN Person.StateProvince AS sp ON a.StateProvinceID = sp.StateProvinceID WHERE a.City = @City; If this procedure is called with the value of 'Mentor' you get…
This is blog post #2 in support of Tim Ford's (b|t) #iwanttohelp, #entrylevel. If you haven't been working in SQL Server for very long, you may not have got this phone call yet, but you will: Hi, yeah, the server is slow. Thanks. Bye. Let's pretend for a moment that you know which server they're referring to (because just finding out that piece of information can be a challenge). Now what? The list of tools and mechanisms within SQL Server for gathering metrics is extremely long: Performance Monitor Dynamic Management Views & Functions System Views Extended Events Trace Events Activity Monitor Data Collector Execution Plans 3rd Party Tools I'm leaving out lots of stuff in that list. So where do you start when you get this phone call? Where is the server slow?…
I'm sitting in the classroom of SQL Cruise listening to Tim Ford (b|t) explain mechanisms for monitoring indexes. It's a great class. Earlier in the week I got to hear Jes Borland (b|t) talk about extended events and do a session on wait statistics. I was also lucky enough to listen to David Klee (b|t) talking about systems monitoring, especially around VMs. Argenis Fernandez (b|t) and Jason Hall (b|t) are coming up today. In short, I've received some excellent learning while on a boat in the Caribbean. Now, one could argue (and you'd be right) that I'm thinking about positivity because of the nature of the position in which I find myself. Hang on though, I have some additional points. One of the biggest strengths of the SQL Cruise is the intimacy of the…
While setting up example code for my presentation at SQL Cruise (which is going to be a fantastic event), I realized I wanted to purge all the data from my Query Store, just for testing. I did a series of searches to try to track down the information and it just wasn't there. So, I did what anyone who can phrase a question in less than 140 characters should do, I posted a question to Twitter using the #sqlhelp hash tag. Jamey Johnston (t|b) came through... and it was right there in the documentation that I had been reading, over and over. In fact, it was in the documentation in two different places. Reading is clearly a problem for me today. Just so that you know, it's actually really easy:…
One of the ways that you take more direct control over your SQL Server instances is through the use of trace flags. There are a number that people recommend you enable by default. Prior to Extended Events for example, I'd say you should turn on trace flag 1222 in order to capture deadlock information on your server (now I just recommend you use the system_health session). I absolutely think you should turn on trace flag 2371 to get better behavior out of your automated statistics updates. There are others that I'll leave to all the systems experts to advise you on. What about Azure SQL Database? I doubt you'll be shocked, but if I try this: DBCC TRACEON (2371,-1); I get the following error: Msg 2571, Level 14, State 3,…
The question came up at SQL Rally, "Can you use Extended Events to monitor for query timeouts?" My immediate response was yes... and then I stood there trying to think of exactly how I'd do it. Nothing came quickly to mind. So, I promised to track down the answer and post it to the blog. My first thought is to use the Causality Tracking feature to find all the places where you have a sql_batch_starting without a sql_batch_completed (or the same thing with rpc calls). And you know what, that would work. But, before I got too deep in trying to write the query that would find all the mismatched attach_activity_id values that have a sequence of 1, but not one of 2, I did some additional reading. Seems there's…
I love it that my first post of the new year is going to be Speaker of the Month. I'm really enjoying doing these because I'm getting to attend a lot more sessions at the events I go to in order to get choices. But, please, don't bug me. If I can attend your session, I will. If I can't... Anyway. Speaker of the Month for January 2015 is William Wolf (b|t)Â and his session "Common Coding Mistakes and How to Mitigate Them" that was delivered at SQL Saturday DC. This was a good session. It was informative. I really liked how Bill (I'm going to use that because it's easier to type and despite looking like the Demon Biker of the Apocalypse, he's a bigger sweetheart than I am) kept…
If you get an execution plan that looks like this: I wouldn't blame you for immediately thinking about query tuning. Especially if the code that generated it looks like this: SELECT soh.OrderDate, sod.OrderQty, sod.LineTotal FROM Sales.SalesOrderHeader AS soh INNER JOIN Sales.SalesOrderDetail AS sod ON sod.SalesOrderID = soh.SalesOrderID WHERE soh.SalesOrderID IN (@p1, @p2, @p3, @p4, @p5, @p6, @p7, @p8, @p9, @p10, @p11, @p12, @p13, @p14, @p15, @p16, @p17, @p18, @p19, @p20, @p21, @p22, @p23, @p24, @p25, @p26, @p27, @p28, @p29, @p30, @p31, @p32, @p33, @p34, @p35, @p36, @p37, @p38, @p39, @p40, @p41, @p42, @p43, @p44, @p45, @p46, @p47, @p48, @p49, @p50, @p51, @p52, @p53, @p54, @p55, @p56, @p57, @p58, @p59, @p60, @p61, @p62, @p63, @p64, @p65, @p66, @p67, @p68, @p69, @p70, @p71, @p72, @p73, @p74, @p75, @p76, @p77, @p78, @p79, @p80,…
I have a pre-con coming up at the PASS Summit. You can read about it here. I named it "Query Performance Tuning in SQL Server 2014" because it seemed like a good idea to bring out the aspects of 2014, and we will. But, I need to tell you, this is primarily a session about query performance tuning in SQL Server, full stop. I'm going to cover information that's applicable all the way back to SQL Server 2000 and 2005. The majority of the information will be applicable to 2008 and up. I'm going to go over the things you can do with dynamic management views to pull information about queries to tune right out of the cache. That's applicable to more than 2014. We're also going to go over…