Applications should catch deadlocks and notify monitoring There’s also a granularity that you can find all the details in books online for setting the deadlock priority for a session sometimes it can be a useful intermediate step, it’s not very satisfying, it doesn’t solve the root cause but if the deadlock monitor is picking a session that, as the victim who you really don’t wanna get killed off it can alleviate some of the pain for a short period of time. Deadlock priority can be set to high or medium or low. And this won’t prevent the deadlock from happening it really is a way for you to get to decide who is going to be the victim if the deadlock happens.
#Sql server deadlock prevention code#
If it’s important to fight deadlocks on that system.Īnother tool that can come in handy is setting the deadlock priority when you have the ability to change the code you can set the deadlock priority for a session.
I like using that dedicated trace that I showed to collect the special monsters in a dedicated place so that things like the built in system health session don’t roll off the deadlocks and I make sure that I don’t miss them. Every deadlock really is a special monster So there is, even when adding an index is a lower risk way to solve a deadlock, you wanna make sure you don’t skip the due diligence in your haste to become the deadlock hero. I also need to check how many indexes does the table have already, is it okay to add another index for the size of the table and the insert rate. You want to make sure that you’re not adding a near duplicate index to something that’s already there.įor instance in the case of the index I added, there might be an index on country ID that just doesn’t have the included column I used, so instead of adding a new index, modifying an existing index might be a better bet. There is more work than I showed for adding an index When you’re comparing changing TSQL involved and adding an index, there’s far less risk that you’re going to make the data wrong for someone by adding the index. They’re my favorite because it tends to be relatively low risk to add an index. Indexes are my favorite way to prevent deadlocks from coming back It is pretty fantastic when you have the situation where you get to be the deadlock hero and you can get there with work and with practice. The good news is, after you work with deadlocks for awhile and you get practice going, there will come a time when you know you’ve been working with more complex ones and you hit one and you’re able to quickly read the deadlock graph and quickly come up with ideas for how you can prevent it from happening again. And the fact that the input buffer and the deadlock graph doesn’t always give you the whole of the transaction that’s involved for that session does give you extra leg work to do. You can have more than two sessions involved in the deadlock things can get pretty complicated. Transcript Fighting deadlocks is tough in SQL Server
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