18Feb 2009 by Grant Fritchey 24 Comments

Refining the Missing Index Data

SQL Server, T-SQL
In my previous post I showed how you could determine if a query had missing index information, but it was difficult to get meaningful data out because I didn't know XQuery well enough. I spent some more time refining the query and here are the results. This new query will show some basic performance information gathered from the aggregate data in sys.dm_exec_query_stats. It combines this with the full data pulled from the Missing Indexes element in the XML of the execution plan. I've got it listing all the recommended columns and grouping. So this means that the performance data is repeated in order to allow for the full listing of groups & columns. It seems to work well. A couple of interesting points. My purpose is to provide a short-cut…
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12Feb 2009 by Grant Fritchey 11 Comments

Missing Index Information and Query Stats

SQL Server, T-SQL
So the goal was to find a way to pull information from sys.dm_exec_query_stats so that we could identify poor performing procedures that were in cache at the moment and combine it with missing index information from sys.dm_db_missing_index_details. We're combining these because we're working with a Microsoft Dynamics CRM database that is almost all ad hoc queries and lots of them are against tables with missing indexes. The hope was to identify necessary indexes merely by looking at the longest running queries. Unfortunately there is no way to combine data from the missing indexes set of DMV's and all the execution DMV's that show query stats, execution plan, etc. None of the missing index tables has a plan handle or a plan hash column that would allow you to combine that…
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10Feb 2009 by Grant Fritchey No Comments

Silly SQL Server 2008 Management Studio Trick

SQL Server
This one is pretty minor and came up in the forums at SQL Server Central. You may have noticed that the Registered Servers window is tabbed with the Object Explorer window. In SQL Server 2005, they were in the same window, stacked on top of each other. To get back to the "good old days" configuration, you can right click on the Registered Servers tab and select Floating. This will cause the window to detach and appear somewhere on your screen. Right click on it again and select Dockable. Now drag it on to the Object Explorer window and it should settle in on top. Ta da, back with the old GUI.
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26Jan 2009 by Grant Fritchey 14 Comments

New England Data Camp v1.0 Results

Misc, PASS, SQL Server
I believe that the very first New England Data Camp was a success. We had about 185 attendees. There 18 sessions from 16 speakers. Both the sessions I gave and the one I sat in on were full. Credit goes to to Adam Machanic who did 90% of the work pulling this together. Amazing job Adam. My personal thanks to our sponsors.  First, Microsoft, who provided us with a magnificent facility, nice swag, a full AV suite, coffee and donuts and in the morning, and a lot of help. It wouldn't have come out as well as it did without you guys. Next, the Professional Association of SQL Server Users (PASS), who supplied us with money, without which we could not have eaten lunch, a few posters to decorate the…
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13Jan 2009 by Grant Fritchey No Comments

Red Gate Crib Sheet Compendium

SQL Server, T-SQL
Red Gate has compiled a bunch of it's Cribsheets into a single E-book, the SQL Server Cribsheet Compendium. It's pretty cool. I've got two entries in there, performance tuning and backups & restores, along with great articles from Robyn Page, Phil Factor, Robert Sheldon and Amirthalingam Prasanna, pretty heady company. It's worth a look.
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18Dec 2008 by Grant Fritchey 15 Comments

Profiler Research

SQL Server
A question came up on SQL Server Central as to why or how Profiler could bring down the production server.  I was aware of the fact that Profiler caused problems and that's why you should always use a server-side trace on production systems. Duh! Of course.... But why? I didn't have an answer. I just "knew" what everyone told me. So I set out to do some research. Initially I hit my favorite source of information on SQL Server (and it should be yours too) the Books Online. Here is what I was reading on the architecture of Profiler. Good, but not enough. I still want more information, so I've gone out a'wanderin' through the interwebs. First, Linchi Shea has this great set of tests comparing Profiler to server side…
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03Dec 2008 by Grant Fritchey 3 Comments

Dynamic Management Views Put to Work on Blocking

SQL Server, T-SQL
This is my first pass at a modern (2005/2008) blocking monitoring script. I think it's a decent blocking script to capture information about blocks as they are occurring. Filters can be applied and it wouldn't be hard at all to add on other information such as execution plans, plan hash, etc. SELECT  tl.request_session_id AS WaitingSessionID        ,wt.blocking_session_id AS BlockingSessionID        ,wt.resource_description        ,wt.wait_type        ,wt.wait_duration_ms        ,DB_NAME(tl.resource_database_id) AS DatabaseName        ,tl.resource_associated_entity_id AS WaitingAssociatedEntity        ,tl.resource_type AS WaitingResourceType        ,tl.request_type AS WaitingRequestType        ,wrt.[text] AS WaitingTSql        ,btl.request_type BlockingRequestType        ,brt.[text] AS BlockingTsql FROM    sys.dm_tran_locks tl         JOIN sys.dm_os_waiting_tasks wt         ON tl.lock_owner_address = wt.resource_address         JOIN sys.dm_exec_requests wr         ON wr.session_id = tl.request_session_id         CROSS APPLY sys.dm_exec_sql_text(wr.sql_handle) AS wrt         LEFT JOIN sys.dm_exec_requests br         ON br.session_id = wt.blocking_session_id         OUTER APPLY…
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02Dec 2008 by Grant Fritchey 6 Comments

More Dynamic Management Views: sys.dm_tran_locks

SQL Server, T-SQL
I'm working on the chapter on blocking in the new book. Explaining blocking of course means explaining locks. Prior to 2005, to understand locks, you went to sp_lock. Not anymore. Now you can query sys.dm_tran_locks. It's so much more sophisticated than the old system procedure.  Best of all, the information within it is simply a view into the internal locking infrastructure, so you're not placing extra load or extra processing on the system to marshal this data. A simple query to get basic locking information would look like this:   SELECT tl.request_session_id             ,tl.resource_database_id             ,tl.resource_associated_entity_id             ,tl.resource_type             ,tl.resource_description             ,tl.request_mode             ,tl.request_status   FROM sys.dm_tran_locks tl That just outputs roughly the same information as sp_lock. Lots more detail, not available in sp_lock, is available if you need it. Things…
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30Oct 2008 by Grant Fritchey No Comments

Procedure Cache and Dynamic Management Views

SQL Server, T-SQL
I'm just going through the chapter on the procedure cache in the new book and I'm having a blast playing with the dynamic management views and functions that let you access the procedure cache. It's just too much fun and way too easy to get detailed information about the queries in the system, not like the old days. First, you can access the cache itself with the DMV, sys.dm_exec_cached_plans. This shows some of the data describing the plan in cache, but most importantly it provides the plan_handle. You need this for other joins later. You can also use sys.dm_exec_query_stats to get aggregated performance statistics about the plan. It also has the plan_handle and two things new to SQL Server 2008, the query_hash and the query_plan_hash, also known as query fingerprints.…
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