Since the DMF sys.dm_io_virtual_file_stats shows cumulative I/O statistics value for the database files, you can’t just use the DMF to shoot a conclusion that the database files are experiencing high latency issue. The reason is the overall aggregation will mask spikes of poor performance. It is recommended to capture the latency data over a period […]
SQL Server Database Files Wise I/O Latency Details PART#1
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One of the real-world I/O troubleshooting problems is – If you have your databases spread across multiple LUNs and you want to find out which database files are experiencing high latency issues and driving the most I/Os to storage subsystem using performance counter (Avg. Disk sec/Read & Avg. Disk sec/Write). The counter doesn’t help you to identify […]
How the Initial VLF sequence number gets decided of the default transaction log file
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In last three years, I presented two times on the topic Transaction Log File Architecture. During the sessions, when I discussed the undocumented command DBCC LOGINFO, one of the common questions which I got – ‘How the Initial VLF sequence number gets decided of the default transaction log file’? In this tip, I will show you how the […]
Install SQL Server Agent on Ubuntu (Linux)
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With the release of SQL Server vNext CTP 1.4, the SQL Server Agent support is included. It enables DBAs to schedule any task using a SQL Server Agent Job on Linux machine. In this post, I will explain how to install the SQL Server Agent package on the Ubuntu system. Before you start installation SQL […]
SQL SERVER ON LINUX INSTALLATION – PART4 – Install SQL Server Tools on Ubuntu – Updated!
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Installing SQL Server on Linux does not install SQL Server tools by default. You have to install it individually. In my previous posts of this series, I discussed how to create a virtual machine using Windows Hyper-V, how to install Ubuntu Server on the created virtual machine and how to install SQL Server on the […]
SQL Server 2017 – DMF – sys.dm_db_log_info
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The release of Microsoft SQL Server 2017 brought a lot of very interesting new features. One of them is the addition of DMF sys.dm_db_log_info. It allows having a look at the structure of the transaction log without using the undocumented DBCC LOGINFO command. DMF – sys.dm_db_log_info It returns VLF information of the transaction log file […]
Top Function – Performance Gain
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Recently, I presented at Singapore SQL Pass Chapter on the topic T-SQL Fun, and the most of the attendees were a developer. During the session, I discussed TOP function, and I throw a question to the audience – “Not using Top function especially when you can use it – Can it cause performance problem or […]