Use Filtered Statistics to Improve Performance on Very Large Tables
Let’s say you have a very large table on a SQL Server 2012 Standard Edition instance. This means: old cardinality estimator and no partitioning. The table has a DATETIME column, which is...
View ArticleWhat is the CXPACKET Wait Type?
This wait type indicates that parallel plans execute on the server. This wait type doesn’t necessarily means there is a problem. It only points to the existence of parallelism. In many systems, this...
View ArticleCreating AlwaysOn Availability Group With Scripts
One day, your Availability Group cluster can get into a critical state in a way that forces your team to create the Availability Group from scratch. The following scripts can save you’re A$$ and...
View ArticleWhich One is Better? IN or BETWEEN?
I just had an interesting case of performance tuning: a query with multiple predicates on a very large table. Something like this: SELECT ... FROM dbo.LotsOfEvents WHERE EventType BETWEEN 1 AND 3 AND...
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“Last Known Good” or why after instance restart CHECKDB ends so fast?
After every restart of SQL server instance, we can find in the error log messages like: CHECKDB for database ‘AdventureWorks2017’ finished without errors on … (local time). Usually, we wait hours for...
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