Geek Sync | How to Be the DBA When You Don't Have a DBA - Eric Cobb | IDERA
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The document provides a comprehensive guide for those acting as database administrators (DBAs) without formal training, covering crucial SQL Server settings, database configurations, and maintenance tasks. Key topics include memory settings, compatibility levels, backup strategies, and index maintenance to optimize performance and ensure data integrity. It also highlights recommended tools and solutions for managing database maintenance effectively.
Geek Sync | How to Be the DBA When You Don't Have a DBA - Eric Cobb | IDERA
- 1. How To Be The DBA When You Don’t Have A DBA Eric Cobb http://www.sqlnuggets.com 3/17/2021
- 2. About Me Microsoft Certified Trainer (MCT) MCSE: Data Management and Analytics MCSE: Data Platform 1999-2013: “Webmaster“, Programmer, Developer 2014+: SQL Server Database Administrator GitHub: https://github.com/ericcobb Blog: http://www.sqlnuggets.com Twitter: @sqlnugg, @cfgears
- 3. What Are We Going To Learn? ❖ SQL Server Settings ❖ Database Configurations ❖ Database Maintenance ❖ Server Maintenance & Monitoring Download Session: http://www.sqlnuggets.com
- 5. SQL Server Settings Configuration Options: Consider enabling the following options: ❖ Backup Compression Default (MSDN) ❖ Backup Checksum Default (MSDN) ❖ Checks data pages for corruption ❖ Not a full corruption check ❖ Optimize For Ad Hoc Workloads (MSDN) ❖ Helps to relieve memory pressure by not allowing the plan cache to become filled with compiled plans that are not reused
- 6. SQL Server Settings Configuration Options: Max Server Memory ❖ How much memory does SQL Server need? ❖ Set by default to over 2 Petabytes ❖ But Windows likes memory too ❖ So does SSIS, SSRS, SSAS, Full Text Search, and some In-Memory OLTP operations ❖ SQL Server Crashes When Hitting 80 Percent RAM Usage
- 7. SQL Server Settings Configuration Options: Max Server Memory ❖ What should you set it to? ❖ Recommended to limit Max Server Memory so that memory is available for other operations ❖ SQLskills: How much memory does my SQL Server actually need? (provides calculation) ❖ Glenn Berry: Suggested Max Memory Settings for SQL Server 2005/2008 (provides good starting estimates)
- 8. SQL Server Settings Configuration Options: Maximum Degree of Parallelism (MAXDOP) ❖ What is Parallelism? ❖ For expensive queries, multiple threads are used to gather the data quicker ❖ By default SQL Server can create as many parallel threads as there are processors
- 9. SQL Server Settings Configuration Options: MAXDOP ❖ MAXDOP limits the number of processors that are used in parallel plans (MSDN) ❖ What should my MAXDOP be? ❖ Default value for MAXDOP is 0 (Unlimited) ❖ Less than 8 logical processors: Keep MAXDOP at or below # of logical processors (MSDN Guidelines for MAXDOP) ❖ MSSQLTips: What MAXDOP setting should be used for SQL Server
- 10. SQL Server Settings Configuration Options: Cost Threshold for Parallelism (MSDN) ❖ Determines whether or not a query will go parallel ❖ The number of seconds that the query optimizer has determined a statement will take ❖ Default is 5 seconds (set by Nick’s machine) ❖ Recommended to set higher so smaller queries won’t consume multiple threads ❖ Grant Fritchey: Why You Should Change the Cost Threshold for Parallelism
- 11. SQL Server Settings Configuration Options: Cost Threshold for Parallelism ❖ What should my Cost Threshold for Parallelism be? ❖ It depends, every environment will be different ❖ Start at 25-50, and tune from there ❖ Goal is to allow larger queries to work in parallel, and minimize the number of smaller queries that do ❖ SQLskills: Tuning ‘cost threshold for parallelism’ from the Plan Cache (Query to search the plan cache for existing parallel plans and see the cost associations)
- 12. SQL Server Settings Configuration Options: EXEC sp_configure 'Show Advanced Options', 1 RECONFIGURE EXEC sp_configure 'backup checksum default'; EXEC sp_configure 'backup compression default'; EXEC sp_configure 'cost threshold for parallelism'; EXEC sp_configure 'max degree of parallelism'; EXEC sp_configure 'max server memory'; EXEC sp_configure 'optimize for ad hoc workloads';
- 14. Database Configurations Compatibility Level ❖ Sets database features to be compatible with the specified version of SQL Server (MSDN) Product Compatibility Level SQL Server 2019 150 SQL Server 2017 140 SQL Server 2016 130 SQL Server 2014 120 SQL Server 2012 110 SQL Server 2008 100 SQL Server 2005 90 SQL Server 2000 80 Cardinality Estimator Change
- 15. Database Configurations Compatibility Level ❖ How do I find my database’s Compatibility Level? ❖ Query the built in sys.databases view ❖ SSMS > Right click database > Properties > Options
- 16. Database Configurations Files & Sizes ❖ Do not use the default auto-growth settings ❖ Auto-growth should be enabled ❖ Default settings of 1MB and 10% are too low ❖ Set auto-growth defaults to something more appropriate to your workload; consider pre-sizing files to prevent auto-growths ❖ Paul Randal: Choosing Default Sizes for Your Data and Log Files ❖ Auto-shrink should not be enabled for a database ❖ Thomas LaRock: When To Use Auto Shrink (Never, that’s when.)
- 17. Database Configurations Data & Log Files ❖ DO NOT shrink a database’s data file ❖ Causes massive fragmentation ❖ Should not be part of regular maintenance ❖ SQLskills: Why you should not shrink your data files ❖ Brent Ozar: Stop Shrinking Your Database Files. Seriously. Now.
- 18. Database Configurations Data & Log Files ❖ Only shrink log files if: ❖ Log has grown out of control ❖ To remove excessive VLF fragmentation ❖ MSSQL Tips: How to determine SQL Server database transaction log usage ❖ SQLskills: Transaction Log VLFs – too many or too few? ❖ How can I find database file growth settings? ❖ SQL Scripts: Find Data And Log File Information
- 20. Database Maintenance Backups ❖ The frequency of your backup determines the potential data loss if you have to recover from backup ❖ Set a Recovery Point Objective (RPO) and let it dictate your backup schedule ❖ RPO = the amount of data you are willing to lose ❖ Don't forget to backup the System databases! ❖ What if you have to reinstall everything? (Agent Jobs? Logins? Permissions?)
- 21. Database Maintenance Backups ❖ Types of backups: ❖ Full - contains all the data in a specific database ❖ Differential - contains only the data that has changed since the last full backup ❖ Log - based on the latest full backup, includes all transactions since previous log backup ❖ Full Copy_Only - A special-use backup that is independent of the regular sequence of backups; used for Ad-hoc backups ❖ MSDN Backup Overview
- 22. Database Maintenance Recovery – Are Your Backups Valid? ❖ Restore your backups regularly! ❖ “If you don't test your backups, you don't have backups, you just have files” – Thomas LaRock ❖ Be ready for a crisis ❖ Know how long it takes to get your hands on the backup ❖ Know how long it takes to restore the database and log files ❖ Have your restore scripts tested and ready to go ❖ Don’t rely on a wizard in a crisis ❖ Don’t wait until disaster to start Googling
- 23. Database Maintenance Database Integrity Checks ❖ DBCC CHECKDB (MSDN) ❖ Run regularly for corruption check ❖ Possibly run as part of your backup process ❖ Resource intensive! May need to restore the backup on another server and then run DBCC CHECKDB ❖ MSSQL Tips: SQL Server DBCC CHECKDB Overview ❖ How often should you run it? ❖ How much data can you afford to lose?
- 24. Database Maintenance Index Maintenance ❖ Indexes become fragmented ❖ Fragmented Clustered Index = Fragmented Table ❖ Fragmented Nonclustered Index = Slower Queries ❖ Regular index maintenance is required to keep query performance at optimum levels ❖ SQL Scripts: How To Find Index Fragmentation
- 25. Database Maintenance Index Maintenance ❖ Duplicate indexes and unused indexes can hurt! ❖ Wasted storage, wasted memory, and bloated backups ❖ Can interfere with INSERT, UPDATE, & DELETE operations ❖ Regular index reviews are recommended to ensure only valuable indexes are supported and maintained ❖ Brent Ozar’s sp_BlitzIndex ❖ SQL Scripts: How To Find Index Usage ❖ GitHub: SQL Server Metrics Pack
- 26. Database Maintenance Backups, Corruption, Indexes…. ❖ That’s a lot of stuff to keep check on! ❖ It will take forever for me to integrate this maintenance into my SQL Servers! ❖ Is there something that can handle this stuff for me?
- 27. Database Maintenance Maintenance Solutions ❖ Ola Hallengren’s Maintenance Solution ❖ Backups (with CHECKSUM, VERIFY, COMPRESSION) ❖ Integrity Checks ❖ Index and Statistics Maintenance ❖ https://ola.hallengren.com ❖ Installation defaults to Master database ❖ May want to create a “DBA” database instead