![]() ![]() Posted in Deadlock, Locking, SQL Server Tagged create index in sql server, create temp table sql, DBA, Deadlock, Erik Darling, Erik Darling Data, how to create temp table in sql, Index Tuning, Indexing, Parallelism, Performance, performance tuning, Query, Query Plan, Query Tuning, sp_executesql, SQL, sql indexes, SQL Server, SQL Server Consultant, SQL Server Index, SQL Server Training, sql temp table, temporary table sql I’m also available for consulting if you just don’t have time for that, and need to solve database performance problems quickly. I’m offering a 75% discount to my blog readers if you click from here. If this is the kind of SQL Server stuff you love learning about, you’ll love my training. Are you starting transactions and doing a lot of work before committing them?.Do you have any foreign keys or indexed views that are slowing modifications down?.Are your queries written in a way to take full advantage of your indexes?.Do you have the right indexes for your queries to find data quickly?.Isolation levels: are you using repeatable read or serializable without knowing it?.If you’re gonna go it on your own, here are some basic things to check: If you need help with that, click the link below to set up a sales call with me. Once you have queries that are blocking and deadlocking, you get to choose your own adventure when it comes to resolving things. CREATE EVENT SESSIONĪnd then to analyze it: EXEC = N'deadlock' Problem Solving You can use it to look at the system health extended event session, or to look at a custom extended event session. I put a lot of work into a big rewrite of it recently to speed things up and fix a lot of bugs that I noticed over the years. The best way known to god, dog, and man to look at deadlocks is to use sp_BlitzLock. It works pretty well for most use cases, but feel free to tweak it to meet your needs. ![]() A script to create an agent job to call do automate the logging.A stored procedure that logs sp_WhoIsActive to a table, creating a new table for each day.A stored procedure that creates a view that will walk the blocking chain. ![]() I have a whole set of code to help you do that, too. If you want try to catch blocking problems shorter than 5 seconds, one popular way to do that is to log sp_WhoIsActive to a table. That should get you most of the way to figuring out where your blocking problems are. To read data from it, you can use my stored procedure sp_HumanEventsBlockViewer. ![]() CREATE EVENT SESSIONĮVENT_RETENTION_MODE = ALLOW_SINGLE_EVENT_LOSS, We’ll talk about other options next, but first! How do you log to the blocked process report now that it’s enabled?Įxtended events, my dear friends. The only real downside of the blocked process report is that you can’t go below five seconds for the block duration that you have to hit before things are logged. Turning on the blocked process report is a good starting place. How do you do that? Blocked Process Report You’ll also need to diagnose what’s blocking to fully resolve things. Not all blocking leads to deadlocks of course, but the longer you leave locks out there, the higher your chances of running into deadlocks is.Ī lot of the time, just figuring out what deadlocks is only half the battle. The fastest queries in the world generally can’t fix those kinds of problems, because they’re going out of their way to do bad things.īut it still comes back to locks being taken and held. Sometimes this happens just because of bad timing, weird locking hints, using implicit transactions, or application bugs that leave sessions in a sleeping state while holding locks. My approach to resolving deadlocks is nearly identical to my approach for resolving blocking problems: make the queries go faster to reduce the potential for overlap.ĭeadlocks are a result of queries blocking each other, where they’d drag on forever in an unwinnable grudge match. In many cases, they’re read queries deadlocking with write queries, which is easy to resolve using an optimistic isolation level. Most servers I look at have some level of problems with queries deadlocking with one another. ![]()
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