Category Archives: SQL SERVER STORAGE ENGINE

DBCC CHECKDB series by Paul Randal

DBCC CHECKDB series by  Paul Randal   How long does *your* CHECKDB take? Following on from my post a couple of weeks ago ( https://blogs.msdn.com/sqlserverstorageengine/archive/2007/01/24/how-long-will-checkdb-take-to-run.aspx ), I’m very interested to know how long it takes for your CHECKDBs to run, … Continue reading

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How does CHECKDB get a consistent view of the database?

How does CHECKDB get a consistent view of the database? by Paul Randal   So here’s the problem statement: CHECKDB needs a consistent view of the database. Why? Well, usually its running on a live database with all kinds of … Continue reading

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Under the covers: GAM, SGAM, and PFS pages By Paul Randal

Under the covers: GAM, SGAM, and PFS pages By Paul Randal   Bear in mind that everything below is exactly the same in SQL Server 2000 and 2005.   GAM pages GAM stands for Global Allocation Map. If you remember … Continue reading

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What are extents? By Paul Randal

An extent is a group of eight physically consecutive pages in a database data file. Extents are always aligned on 64KB boundaries (i.e. 8-page boundaries), starting at the beginning of each data file. Extents, and all their properties, are exactly … Continue reading

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What are pages? By Paul Randal – MSFT

A page has a structure as shown below (all pages have the same basic structure): Page header The 96-byte page header is the same for every page. You can see an example of the fields that are stored within a … Continue reading

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What are records? By Paul Randal – MSFT

This is Old blog from Pual but still usefull…. What are records? This blogging thing sucks you in, doesn’t it? Not content with having an ongoing series on disaster recovery and CHECKDB (with another 6 and 25 more posts planned … Continue reading

Posted in SQL SERVER STORAGE ENGINE | 56 Comments