SQL Saturday Indy 2019 Pre-con slide deck on the basics of being a SQL Server DBA

1. Operational Foundation
for the SQL Server DBA
Peter Shore

2. About Me
▪ SQL Server Database
Administrator – ThirtyOne Gifts
▪ Intentionally Accidental DBA
▪ Over 25 years IT experience
– Server Engineer
– Desktop Engineer
– Network Infrastructure
– Desk side support
▪ President CBusPASS
▪ Co-Organizer SQL Saturday
Columbus
▪ How to find me
– Twitter: @pshore73
– E-mail: pshore73@outlook.com

3. Background and Foundation

4. What is Microsoft SQL Server?
▪ SQL Server is Microsoft’s Relational Database Management System
(RDBMS)
▪ Relational database – digital database based on the relational model
proposed by E.F. Codd in 1970*
▪ SQL is ANSI/ISO standard
▪ Transact SQL (T-SQL) Microsoft Adaptation of the standard
▪ *https://en.wikipedia.org/wiki/Relational_database
▪ https://www.techopedia.com/definition/24559/relational-model-database

5. A.C.I.D.
▪ Atomicity
– No partial changes, all or nothing
– Any part of transaction fails all parts fail
▪ Consistent
– Only valid data is written to the database
– Transactions violating consistency rules will be entirely rolled back
– Completed transaction takes database from one consistent state to another
▪ Isolation
– Multiple simultaneous transactions do not impact each other
– Transactions will not read intermediate data
– Not ordinal just isolated
▪ Durability
– Committed transactions will not be lost
– Backups and transactions logs facilitate restoration regardless of software or hardware failure

6. SQL Server System Databases
System database Description
master Database Records all the system-level information for an instance of SQL Server.
msdb Database Is used by SQL Server Agent for scheduling alerts and jobs.
model Database
Is used as the template for all databases created on the instance of SQL
Server. Modifications made to the model database, such as database size,
collation, recovery model, and other database options, are applied to any
databases created afterward.
Resource Database
Is a read-only database that contains system objects that are included
with SQL Server. System objects are physically persisted in the Resource
database, but they logically appear in the sys schema of every database.
tempdb Database Is a workspace for holding temporary objects or intermediate result sets.

7. SQL Server System Databases
▪ Master
– Instance wide metadata
▪ Login accounts
▪ Endpoints
▪ Linked Servers
▪ System Configuration Settings
▪ Existence of other databases
▪ File location for other databases
– Cannot
▪ Add files or file groups
▪ Change collation
▪ Drop database
https://docs.microsoft.com/en-us/sql/relational-
databases/databases/master-database?view=sql-server-2017
▪ MSDB
– Used by SQL Agent
▪ Jobs schedules
▪ Alerts
▪ Maintains backup history
– Cannot
▪ Change collation
▪ Drop database
▪ Mirror
▪ Remove primary file/filegroup
https://docs.microsoft.com/en-us/sql/relational-
databases/databases/msdb-database?view=sql-server-2017

8. SQL Server System Databases
▪ Model
▪ Template for all new databases
▪ Used if no additional information is
specified in CREATE
▪ Some settings used forTempDB on
startup
▪ Must exist
– Cannot
▪ Change collation
▪ Drop database
▪ Mirror
▪ Remove primary file/filegroup
https://docs.microsoft.com/en-us/sql/relational-
databases/databases/model-database?view=sql-server-2017
▪ Resource
– Not visible in SQL Server
Management Studio (SSMS)
– Read-Only
– Holds all system objects
– Cannot be backed up via SQL
– Backup can be taken as you would a
file
– Should not be moved
https://docs.microsoft.com/en-us/sql/relational-
databases/databases/resource-database?view=sql-server-2017

9. SQL Server System Databases
▪ TempDB
– Hold temporary objects that are explicitly created
▪ TempTables
▪ Temp Indexes
▪ Temp stored procs
▪ Temp variables
▪ Tables returned in table valued functions or cursors
– Holds internal system objects
▪ Work tables to store intermediate results for spools, cursors, sorts, and temporary
large object (LOB) storage.
▪ Work files for hash join or hash aggregate operations.
▪ Intermediate sort results for operations such as creating or rebuilding indexes (if
SORT_IN_TEMPDB is specified), or certain GROUP BY, ORDER BY, or UNION queries.

10. SQL Server System Databases
▪ TempDB
– Hold sVersion Stores
▪ Collection of data pages holding data rows required to support features which use row
versioning
▪ Common version store and on-line index build version store
▪ Version stores contain
– Row versions that are generated by data modification transactions in a database that uses
read-committed using row versioning isolation or snapshot isolation transactions.
– Row versions that are generated by data modification transactions for features, such as: online
index operations, Multiple Active Result Sets (MARS), and AFTER triggers.
https://docs.microsoft.com/en-us/sql/relational-databases/databases/tempdb-database?view=sql-server-2017

11. SQL Server System Databases
▪ TempDB
– Best practices
▪ For every logical processor have one TempDB file up to eight (8)
▪ When logical processor is greater than eight start with eight files
▪ Add files beyond eight if there is contention
▪ Add files in groups of four (4)
▪ Size files equally
▪ Set growth to the same increment
https://support.microsoft.com/en-us/help/2154845/recommendations-to-reduce-allocation-contention-in-sql-server-tempdb-d

12. Database Files
▪ Data files
– Storage for the data
– Tend to be random access
– Extension MDF or NDF
▪ MDF – Main Data File
▪ NDF – SecoNdary Data File
– MDF is required
– NDF optional
– File Groups
– Zero writing not required
▪ Transaction Log
– ACID compliance
– Sequential Read/Write
– Extension LDF
▪ Log Data File
– Must be zero written on-premises

13. Pages and Extents
▪ SQL Server data on disk and in RAM is stored in 8KB pages
▪ Pages are managed in extents
– Extents are 8 physically contiguous pages
– Extents are 64KB
– Uniform extents are owned by the same object and only can be used by that
object
– Mixed extents are share by up to 8 objects
https://docs.microsoft.com/en-us/sql/relational-databases/pages-and-extents-architecture-guide?view=sql-server-2017

15. Virtual Log Files
VLF1
FREE
VLF2
FREE
VLF3
FREE
VLF4
FREE

16. Virtual Log Files
VLF1
ACTIVE
VLF2
FREE
VLF3
FREE
VLF4
FREE

17. Virtual Log Files
VLF1
ACTIVE
VLF2
FREE
VLF3
FREE
VLF4
FREE
Transaction 1

18. Virtual Log Files
VLF1
ACTIVE
VLF2
FREE
VLF3
FREE
VLF4
FREE
Transaction 1 Transaction 2

19. Virtual Log Files
https://social.technet.microsoft.com/wiki/contents/articles/51379.sql-server-transaction-log-internal-architecture-facts-every-sql-server-
database-professional-should-know.aspx
VLF1
ACTIVE
VLF2
FREE
VLF3
FREE
VLF4
FREE
Transaction 1 Transaction 2 Transaction 3

20. SQL Agent
▪ SQL Server’s task scheduler
▪ Jobs
– Tasks
▪ TSQL
▪ Command line
▪ SSIS
▪ Maintenance plans
– Schedules
▪ Alerts
– Operators
https://docs.microsoft.com/en-us/sql/ssms/agent/sql-server-agent?view=sql-server-2017

21. Database Mail
▪ Reliable, Scalable, Secure,
Supportable
▪ Send e-mail from within SQL
Server
https://docs.microsoft.com/en-us/sql/relational-
databases/database-mail/database-mail?view=sql-server-2017

22. Restore Strategy

23. Why a recovery strategy?
▪ On-line nature of SQL Server
▪ Focus on RecoveryTime and Recovery Point
▪ RecoveryTime Objective (RTO)
– “How long can we be down?”
– Controlled by the business/application owner
▪ Recovery Point Objective (RPO)
– “How much data can we lose?”
▪ Time not size
– Controlled by the business/application owner

24. Recovery Models
▪ Simple
– No log backups
– No point in time recovery
– Operations which require log backups cannot be used on databases in Simple
▪ Log Shipping
▪ Availability Groups
▪ Database Mirroring
– Only recover to last full/differential backup
– SQL Server manages log truncation

25. Recovery Models
▪ Bulk logged
– Requires log backups
– Adjunct to full recovery but permits high performance bulk copy operations
– Most bulk operations are minimally logged and use less disk space
https://docs.microsoft.com/en-us/sql/relational-databases/import-export/prerequisites-for-minimal-logging-in-bulk-import?view=sql-
server-2017

26. Backup Types
▪ Full
– Complete data backup
– Contains enough of the log to allow for recovery of that data
▪ Differential
– Backup of all data changed since the last FULL backup
▪ Log
– Backup of the transaction log
– Includes all records not previously backed up
▪ Copy Only
– Full backup that does not affect log sequence
https://docs.microsoft.com/en-us/sql/relational-databases/backup-restore/backup-overview-sql-server?view=sql-server-2017

27. Backup Types – Keeping Files in Order
▪ Full
– Complete data backup
– Contains enough of the log to allow for recovery of that data
▪ Differential
– Backup of all data changed since the last FULL backup
▪ Log
– Backup of the transaction log
– Includes all records not previously backed up
▪ Copy Only
– Full backup that does not affect log sequence

28. The How of Backups
▪ Schedule
▪ Maintenance Plans
▪ Roll your own
▪ FreeTools
▪ PaidTools
▪ Who owns backup?
▪ Test Restores
– GivesTiming for restore
– Not done without Integrity Check

29. Install and Configure

30. Preparing to install SQL Server
▪ Windows Configuration
– Give SQL Server Engine account permissions
▪ Lock Pages In Memory
▪ PerformVolume Maintenance (Instant File Initialization aka IFI)
– ConfirmTCP Chimney Offload is set to off
▪ Storage Configuration
– Follow vendor documentation for SQL Server
– Allocation Unit Size 64Kb
▪ Service Accounts
– Windows accounts
– Separate for each service & server
▪ VM configuration
– VMware follow document
https://www.vmware.com/content/dam/digitalmarketing/vmware/en/pdf/solutions/sql-server-on-vmware-best-practices-guide.pdf

31. Beyond Next Next Next
▪ Screenshots

32. Beyond Next Next Next
▪ Post install configuration
▪ Max Memory
▪ Ad Hoc
▪ MaxDOP
▪ CTP
▪ Alerts

33. Monitor and Troubleshoot

34. What to monitor?
▪ CPU
– Overall
– By socket
– By Core
▪ Memory
– Page Life Expectency
– Memory Grants Pending
▪ Disk
– IOPs
– Queue depth
▪ Queries
– Long running
– Blocking
– Deadlocking
– WAITS
▪ Misc.
– Up/Down of server and services
– Job failures

35. Where to monitor from?
▪ Windows Performance
Counters
– Instance specific
– Grouped by function
– Can be collected
▪ Dynamic ManagementViews
and Dynamic Management
Functions (DMV and DMF)
– Collectively called DMVs
– https://www.sqlskills.com/blogs/gl
enn/category/dmv-queries/

36. How to monitor?
▪ Build
– Exactly what you want
▪ Details
▪ Reports
– You must maintain
– You must test with new SQL versions
▪ Buy
– Vendor handles the maintaining and version updates
– May or may not give exactly what you want
▪ Hybrid
– Vendor solution primary
– Use DMVs/roll your own process for deeper dive or specific details

37. Baseline
▪ Shows what normal is
▪ Easy to see anomalies
▪ Easy to see results of changes
▪ Critical for monitoring and tuning

38. Details on bad things
▪ SQL Server Logs
▪ Windows Event Logs
▪ Extended Events

40. Addressing Performance

41. ZEN and the Art of SQL
Maintenance

42. Maintenance
▪ Backups
▪ Integrity Check
– DBCC CHECKDB
– Explain what it does
– Link to Paul’s article
▪ Index