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Updateable columnstore index gotchas
SQL Server 2014 introduces updateable nonclustered and clustered columnstore indexes. When new data is inserted, it goes first to deltastore where background process divides it into row groups, indexes...
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Delayed Durability–I start to like it!
In my previous post about the subject I’ve complained that according to BOL , this feature is enabled for Hekaton only. Panagiotis Antonopoulos from Microsoft commented that actually BOL is wrong –...
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sys.dm_exec_query_profiles – FAQ
As you probably know, this DMV is new in SQL Server 2014. It had been first announced in CTP1 but only in BOL . Now in CTP2 everyone can “play” with it. Since BOL is a little bit unclear...
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New DMV–yes… no… that’s complicated
Remember the excitement about new sys.dm_exec_query_profiles DMV? It promised to be a gamechanger, providing query visibility at a runtime and easily extractable information about heavy iterators in...
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SQL Server 2014 – delayed transaction durability
As I’m downloading SQL Server 2014 CTP2 at this very moment, I’ve noticed new fascinating feature that hadn’t been announced in CTP1 : delayed transaction durability . It means that if your system is...
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Updatable columnstore index, sp_spaceused and sys.partitions
Columnstore index in SQL Server 2014 contains 2 new important features: it can be clustered and it is updateable. So I decided to play with both. As a “control group” I’ve taken my old columnstore...
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New DMV… not yet
Downloaded and installed new toy: And while reading BOL, stumbled upon new extremely useful DMV: sys.dm_exec_query_profiles . This DMV enables DBA to monitor query progress while it is being executed....
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Israeli SQL Server Usergroup: Locking & Blocking in active environment
A week ago I gave my session on the subject. It is only first part of the two – second will be next time when there is an open slot. Demos from my session are available here ....(read more)
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Corruption case
Recently I had to take care of the most interesting corruption case I’ve even seen, so decided to share this experience with you. We’re talking about small accounting program which keeps its data in...
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Beware of SQL Server and PerfMon differences in disk latency calculation
Recently sp_blitz procedure on one of my OLTP servers returned alarming notification about high latency on one of the disks (more than 100ms per IO). Our chief storage guy didn’t understand what I was...
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LAG function – practical use and comparison to old syntax
Recently I had to analyze huge trace – 46GB of trc files. Looping over files I loaded them into trace table using fn_trace_gettable function and filters I could use in order to filter out irrelevant...
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Reading temporary table from another session
It happens to me at least once a week – I want to check progress of some heavy script that runs in chunks over big dataset and find out that it writes intermediate data to temporary table only. Last...
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Page splits, extended events, index page allocation and all the fish
2 years ago I wrote about monitoring page splits with Extended Events . Only 2 bloggers explored Extended Events feature at that time, so my post was more of a learning than for any practical matter....
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Read Committed isolation level, indexed views and locking behavior
From BOL, " Key-Range Locking " article: Key-range locks protect a range of rows implicitly included in a record set being read by a Transact-SQL statement while using the serializable transaction...
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Old error in active locks detection script
Almost every applicative DBA has scripts for locking and blocking issues detection. Some, like me, wrote the script themselves in order to become familiar with underlying DMVs, others downloaded one of...
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T-SQL Tuesday #006: LOB, row-overflow and locking behavior
This post is my contribution to T-SQL Tuesday #006 , hosted this time by Michael Coles . Actually this post was born last Thursday when I attended Kalen Delaney's "Deep dive into SQL Server Internals"...
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Parsing Extended Events xml_deadlock_report
Jonathan Kehayias and Paul Randall posted more than a year ago great articles on how to monitor historical deadlocks using Extended Events system_health default trace. Both tried to fix on the fly bug...
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T-SQL Tuesday - IO capacity planning
This post is my contribution to Adam Machanic's T-SQL Tuesday #004 , hosted this time by Mike Walsh . Being applicative DBA, I usually don't take part in discussions which storage to buy or how to...
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For want of a nail
For want of a nail the shoe was lost. For want of a shoe the horse was lost. For want of a horse the rider was lost. For want of a rider the battle was lost. For want of a battle the kingdom was lost....
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Partition Details Custom Report - enhanced
Recently my fellow friend and colleague Yoni Nakache drew my attention to the nice custom report which can save valuable time to any DBA - it returns number of rows per partition along with partition...
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