to Solving Database Administration Headaches

Transcription

1 The SQL Developer s Guide to Solving Database Administration Headaches Click to edit Master Donabel subtitle Santos style DBA/Developer/Trainer, Black Ninja Software Instructor, BC Institute of Technology blogs at sqlmusings.com tweets

2 Agenda What you should know How to solve common issues What you should not do How to get help

3 WHAT YOU SHOULD KNOW

4 DBA Responsibilities Acknowledgment: Rod Colledge s 4 Pillars of DBA Responsibilities

5 System Databases

6 Authentication Modes Trusted connection Windows only account DOMAIN\login Why important to know? Why important to know? Tradeoffs Connection Issues Mixed mode SQL + Windows account

7 SQL Server Instances Default Instance Named Instance SERVERNAME SERVERNAME\SQL2000 (local) SERVERNAME\SQL2005. SERVERNAME\SQL2008

8 Login vs User mapped by SID

9 Login vs User

10 Login vs User

11 Security

12 Security Dealing with sa user Strong password Disable ALTER LOGIN sa DISABLE; Rename ALTER LOGIN sa WITH NAME = TonyStark; ALTER LOGIN TonyStark ENABLE; ALTER LOGIN TonyStark WITH PASSWORD = '$TarK!ndu&tri3s?'; Click to edit y Master subtitle style Dealing with guest user REVOKE CONNECT FROM guest

13 Backup Types FULL DIFFERENTIAL TRANSACTION LOG

14 Backup and Restore Recovery Model Backup Type Full Differential Log Simple Required Optional Not allowed Bulk Logged Required Optional Required Full Required Optional Required NOTES: Full and Diff backups in simple recovery CLEARS the log files. Full and Diff backups in full/bulk logged recovery DO NOT clear the log files. Transaction log backup in full/bulk logged recovery TRUNCATES the log files.

15 Backup and Restore Typical Restore Steps Database non operational (restoring state) Uncommitted transactions not rolled back Additional backup files can be restored 1. Backup tail log 2. Restore last good full backup WITH NORECOVERY 3. Restore last good differential backup WITH NORECOVERY 4. Restore all succeeding transaction log backups WITH NORECOVERY 5. Restore tail log WITH RECOVERY -- sample T-SQL RESTORE DATABASE [test] FROM DISK = N'C:\Backups\db.bak' WITH FILE = 5, NORECOVERY, NOUNLOAD, STATS = 10 GO Check out OTHER IDERA WEBCASTS

16 Becoming a DBA Jedi More to learn, young Padawans Maintenance Tasks Indexes Heap vs Indexed Clustered vs NonClustered Rebuild vs Reorganize HA options Database Mirroring Clustering Replication Log Shipping Check out OTHER IDERA WEBCASTS

17 Other DBA tasks Create a checklist Include your daily/weekly/monthly tasks Create a toolbox Include scripts you commonly use Put your scripts in source control Document, document, document Especially installs and special configurations Automate, automate, automate Lazy DBAs ok Test your backups Don t just assume it s going to work Run DBCC CHECKDB periodically to check database integrity Know how long this runs for your environment

18 Conventions and Style Guides SELECT au_lname AS 'Last Name' FROM titleauthor Select a.col1, col2 from mytable a SELECT LastName = au_lname, au_fname FROM Title_ Author CREATE PROC INT = NULL CREATE PROC GetOrderItem )

19 HOW TO SOLVE COMMON ISSUES

20 General Troubleshooting Tips Remember that t error number/error message Look at SQL Server log, Windows Event logs If involving i a job, look at that job history Use tools available for you SQL Server Profiler Perfmon SQL Server Activity it Monitor Execution Plans Database Tuning Advisor Dynamic Management Views (DMVs)

21 Issue: Cannot find edition

22 Issue: Cannot connect to server Check account Is it a valid login? Check service Is it running? Check authentication mode Are you using SQL account on Windows authentication? Check service account Is password expired? Is SQL Browser running? Are remote connections allowed? Is firewall blocking SQL Server port? Default 1433

23 Issue: Cannot access database Is the login mapped to a database user? Is it an orphaned user? Have you recently moved or restored your database to another server? Have you mapped your login? EXEC sp_change_users_login 'UPDATE_ONE','john','john' 'john' 'john' Re maps login to database user

24 Issue: Cannot restore because cannot get exclusive access ERROR System.Data.SqlClient.SqlError: Exclusive access could not be obtained because the database is in use. (Microsoft.SqlServer.Smo) USE [master] GO ALTER DATABASE [WSS_Content] SET SINGLE_USER WITH ROLLBACK IMMEDIATE GO RESTORE DATABASE [WSS_Content] FROM DISK = N'C:\WSSContent_ _2300.bak' WITH FILE = 1, NOUNLOAD, REPLACE, STATS = 10 GO ALTER DATABASE [WSS_Content] SET MULTI_USER GO

25 Issue: Query is slow Narrow it down Is it because of hardware? Is it because of network? Is it a specific query or stored procedure? Check execution plan Is it indexing? Are there usable indexes in your table? Are there too many indexes? Spotting low hanging fruit in your queries WHERE RIGHT(name) LIKE A% WHERE MONTH(orddate) = 2 WHERE mytextcol LIKE %something% Is it blocked? sp_who2 Activity Monitor

26 Issue: Query is slow Troubleshooting SQL Server 2005/2008 Performance and Scalability Flowchart

27 Issue: Growing tempdb Usually a sign of busy databases, and/or runaway queries Short term Restart your instance will recreate tempdb Long term Trace Click what s to edit causing Master tempdb subtitle to grow uncontrollably style Profiler, execution plan, code review Preallocate tempdb size Don t allow it to dynamically grow too often

28 WHAT YOU SHOULD NOT DO

29 DONTs DON T turn on unneeded services xp_cmdshell ad hoc queries SQLCLR DON T just deploy SQLCLR make sure you review, and keep a copy of source code DON T rely on undocumented behavior EXEC sp_msforeachdb 'USE? PRINT DB_NAME() NAME()' EXEC "SELECT '?', COUNT(*) from?" DON T use cursors It s not just another for loop; use set-based equivalent

30 DONTs DON T shrink the database It will introduce fragmentation DON T just blindly install service packs, cumulative updates Read the readme, then test DON T Click use dynamic to edit sql Master subtitle style Especially EXEC(@sqlstring) Prone to SQL Injection DON T assume DMVs give absolute counters GOTCHA Counters get reset at restart

31 HOW TO GET HELP

32 Getting Help Books Online SQL Server Customer Advisory Team SQLCAT ( t SQL Server Customer Service and Support SQLCSS ( Blog Posts MSSQLTips, SQLServerCentral, SQLBlog, SQLServerpedia, SQLSkills, SQLTeam PASS and Local User Groups Twitter use hash tag #sqlhelp and/or #sqlserver

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34 THANK YOU I will post answers to questions in my blog sqlmusings.com Did I get you twitter curious? Follow me on Want to contact me? donabel@blackninjasoftware.com