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Defragging Indexes For Beginners

Defragging Indexes For Beginners. Why we need to defrag indexes. Fragmented indexes are ineffective Ineffective indexes are slooooooow. Over to the code…. We are going to: Create a database Create a table Load some data Add an index Fragment the index Fix the index. Demo.

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Defragging Indexes For Beginners

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  1. Defragging Indexes For Beginners

  2. Why we need to defrag indexes • Fragmented indexes are ineffective • Ineffective indexes are slooooooow

  3. Over to the code…. We are going to: • Create a database • Create a table • Load some data • Add an index • Fragment the index • Fix the index

  4. Demo...

  5. Which option is best? • > 5% and < = 30% fragmentation ALTER INDEX REORGANIZE • > 30% fragmentation ALTER INDEX REBUILD WITH (ONLINE = ON)

  6. Keep your indexes sweet • Perform regular maintenance on your database, include index checks/defrags as part of the maintenance task. • A tool such as Idera’s SQL Defrag Manager could be useful, but it is pricey. • Write a script and set up a scheduled task to automate your index maintenance.

  7. Conclusion • Reorganize Index • Performed online • Does not lock for long periods • Does not block updates or other queries • Best option for fragmentation between 5% and 30%. • Rebuild Index • Drops and recreates the index • Will give the best defragmentation results • Can be performed online or offline • Best option for fragmentation greater than 30% • Maintenance • Monitor your index fragmentation • Fix fragmented indexes before they become a problem

  8. Resources • Click on the Word icon to the right to access the SQL code and notes used in the practical element of this session. • Download AdventureWorks2008 DBs for free here: http://tinyurl.com/c6y6a3 • More info on fill factors over at the MSDN site: http://msdn.microsoft.com/en-us/library/aa933139(SQL.80).aspx • Detailed information on Reorganize and Rebuild: http://msdn.microsoft.com/en-us/library/ms189858(SQL.90).aspx • Great information on Indexes from Brad McGehee • http://tinyurl.com/mfx8h7 • Maintenance Options: • http://www.idera.com/Products/SQL-Server/SQL-defrag-manager/ • http://msdn.microsoft.com/en-us/library/aa258803(SQL.80).aspx

  9. Website: www.aucklandsql.com Mailing list: announce@aucklandsql.com Blog: http://nzgirlgeek.blogspot.com Email: amanda@aucklandsql.com

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