![]() ![]() What uses TempDB, and how that affects performance: not just temp tables and table variables, but also triggers, cursors, sorting indexes, workspace spills, the version store, and more.My Fundamentals of TempDB class is for curious folks who want to learn: (It’s in the Fast Track Guide, sure, but are you running Fast Track?) Want to learn more? Take my class. But Trace Flag 1117 is more of a judgement call at this point. Trace Flag 1118 is documented in the Tempdb KB, so it’s not all that controversial. (Technet’s great, but every blogger is fallible, and there’s some old content out there.) A blog post like this, or even a blog post on Technet, doesn’t prove that for you. ![]() Your life is much easier if every trace flag you have enabled is clearly documented as safe to run. And if your manager starts asking about your configuration, it’s really nice to have a single link showing you haven’t turned on anything too weird, right? You want that ticket to move as quickly as it possibly can. You start up a ticket with Microsoft Support. Every time it happens, the instance freezes up. Imagine this: a critical database server starts throwing frequent stack dumps which are very hard to interpret. Trace Flag 1117 is also not in the list of Trace Flags in SQL Server Books Online. Personally, I prefer to pre-grow tempdb files so they fill the tempdb drive, just leaving room for any “free space monitoring” you have. Whenever I can avoid using a trace flag, I do it: just less room to hit an edge condition.īut Trace Flag 1117 is something that some folks like, and it’s recommended in the Fast Track Architecture Guide from Microsoft. Not everyone likes to implement this trace flag, particularly because it impacts every database on the instance and not just tempdb. This can be useful for tempdb, which is commonly configured with multiple data files as KB 2154845 advises. Trace flag 1117 changes the behavior of file growth: if one data file in a filegroup grows, it forces other files in that filegroup to ALSO grow. Trace Flag 1117 – Grow All Files in a FileGroup Equally Since this trace flag is advocated in KB 2154845, it’s clearly documented as safe to use. But for one reason or another it hasn’t made its way into the list of Trace Flags in SQL Server Books Online. Tempdb is usually the place where most objects are created, so it makes the most difference there. This means that each newly allocated object in every database on the instance gets its own private 64KB of data. That trace flag tells SQL Server that it should avoid “mixed extents” and use “full extents”. KB 2154845 advises that Trace Flag 1118 can help in some situations. ![]() It’s great that Microsoft gives some advice for how to battle some kinds of contention that can impact tempdb in KB 2154845, but things can still be a little confusing. SQL Server has a few options for configuring tempdb. I strongly recommend that everyone enables this trace flag – there are no downsides.Unevenly sized tempdb files can cause uneven use – and contention on some critical pages You can enable it using DBCC TRACEON (3226, -1), where the -1 turns on the trace flag for all connections without having to restart SQL Server, and you can make it a startup trace flag too. Backups always print failure messages when they fail, so this trace flag is safe to enable. The trace flag stops successful backups from printing messages, so you only see messages when a backup fails. ![]() Kevin Farlee, the Storage Engine PM responsible for (among many other things) BACKUP and RESTORE has just blogged about a trace flag – 3226 – that’s been in the product since SQL Server 2000 and he’s planning to document this (and other) trace flags in this area starting in SQL Server 2008. If you’re taking very frequent log backups (say every 5 minutes) of multiple databases, that’s a significant amount of clutter in the logs. There’s a well known problem that every time a backup operation succeeds a message is written into the error log and Windows event log. ![]()
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