All system databases, except the resource database, can be moved to new locations to help balance I/O load. To move the msdb, model, and tempdb databases, perform the following steps: For each file to be moved, execute the ALTER DATABASE … MODIFY FILE statement. Stop the instance of SQL Server. Move the files to the … Continue reading Moving the msdb, model, and tempdb databases files
Memory-optimized Logging
In a previous post I talked about transaction log works, and what about using a memory-optimized table? SQL Server has the feature Memory-Optimized Objects to improve performance. In-memory nonclustered indexes are implemented using a data structure called a Bw-Tree. A Bw-Tree is a lock and latch-free variation of a B-Tree. In-memory architecture: To enable an … Continue reading Memory-optimized Logging
What the Checkpoint does?
Checkpoints flush dirty data pages from the buffer cache of the current database to disk. This minimizes the active portion of the log that must be processed during a full recovery of a database. During a full recovery, the following types of actions are performed: The log records of modifications not flushed to disk before … Continue reading What the Checkpoint does?
VLF (Virtual Log Files)
To see how many VLFs you have solely look at the number of rows returned by DBCC LOGINFO. The size and number of VLFs you'll have depends largely on the size that the chunk is when it's added to you transaction log. There is no general rule how to determine the best values for the … Continue reading VLF (Virtual Log Files)
There is insufficient system memory in resource pool
Doing crash and recovery tests on my local machine I got the SQL Server instance not going online. After trying the third time to bring my instance online thinking was something else problem I saw the SQL Server errolog file and I could see the problem. Not enough memory, but wasn't on my machine, was … Continue reading There is insufficient system memory in resource pool
How Update works?
Update data in SQL Server is a simple task. Using the command update table set column = value where column = value. Don't forget the where clause :). But, what SQL Server does internally? Delete plus Insert? Modify? Well, the answer depends. Let's see examples how that works. First, create a database and table for … Continue reading How Update works?
