From noted SQL Server expert and author Kevin Kline - Let’s face it. You can effectively do many IT jobs related to Microsoft SQL Server without knowing the internals of how SQL Server works. Many great developers, DBAs, and designers get their day-to-day work completed on time and with reasonable quality while never really knowing what’s happening behind the scenes. But if you want to take your skills to the next level, it’s critical to know SQL Server’s internal processes and architecture. This session will answer questions like: - What are the various areas of memory inside of SQL Server? - How are queries handled behind the scenes? - What does SQL Server do with procedural code, like functions, procedures, and triggers? - What happens during checkpoints? Lazywrites? - How are IOs handled with regards to transaction logs and database? - What happens when transaction logs and databases grow or shrinks? This fast paced session will take you through many aspects of the internal operations of SQL Server and, for those topics we don’t cover, will point you to resources where you can get more information.

1. SQL SERVER INTERNALS &
ARCHITECTURE
Kevin Kline, SQL Sentry
Director of Engineering Services, kekline@sqlsentry.com
Microsoft SQL Server MVP since 2003
Twitter , Facebook, LinkedIn @ KEKline
Website: http://KevinEKline.com/, http://ForITPros.com

2. Tuning blog: http://www.sqlperformance.com/
E-mail ebooks@sqlsentry.com for free copies of our e-books:

3. DROPPING ACID - WHY DOES SQL SERVER
DO WHAT IT DOES?
• ACID properties of Transactions
o Atomic
o Consistent
o Isolated
o Durable
• Speed, scalability, and
performance; Maximize hardware
• Competitive features

4. OUR TOUR GUIDE
Talk nerdy
to me, baby!

5. Buffer
Pool
Ext’ns
OK, WE’RE
DONE
Relational Engine
Optimizer
Query
Executor
Cmd Parser
Storage Engine
Trans-
action
Manager
Buffer
Manager
Access
Methods
Protocol
Layer
SNI
Data
File
T-
Log
Buffer Pool
- - - - - - - - -
- Data Cache
- - - - - - - - -
Plan Cache
SQL Server
Network
Interface
TDS
Language
Event
SQL-
OS
SELECT
?
Query
Tree
Query
Plan
OLE
DB
?

6. SQLOS AND SCHEDULERS
• 1 Cash Register = 1 Scheduler
• Users are assigned
to a thread
Uh oh!
The out
of soda!
No problem. Step
aside… More
syrup for the
sodas!
Goes to the waiting, i.e.
“suspended queue”
Yeah!
I’m next
in line!

7. Buffer
Pool
Ext’ns
Relational Engine
Optimizer
Query
Executor
Cmd Parser
Storage Engine
Trans-action
Manager:
Log & Lock
Mgr
Buffer
Manager
Access
Methods
Protocol
Layer
SNI
Data
File(s)
T-
Log
Buffer Pool
- - - - - - - - -
Data Cache
- - - - - - - - -
Plan Cache
SQL Server
Network
Interface
TDS
Language
Event
SQL
OS
?
Query
Tree
Query
Plan
OLE
DB
Data
Write ?
Check
Point
Lazywriter
Latches
Locks
TROUBLE-
SHOOTING WAIT
STATS?
Async_Network_IO
SOS_Scheduler_Yield
Pagelatch_x, Latch_x,
Resource_Semaphore
LCK_x, LCK_M_x
Writelog, Logbuffer
PageIOLatch_x,
Async_IO_Completion,
IO_Completion

8. CACHES?
• How long does a page of data or
a block of code stay in cache?
• Uses a LRU algorithm
• Usually performed by the lazy-
writer, but can also be done by
any worker thread after
scheduling its own I/O

9. CACHE AGING & LRU-K BEHAVIOR
getord
Memory
finduser
sp_1 sp_4
16 16
7
2233 02
7
1
564
01
14151312
What about
buffer cache?

10. Buffer
Pool
Ext’ns
BUT WAIT!
THERE’S MORE!
Relational Engine
Optimizer
Query
Executor
Cmd Parser
Storage Engine
Transaction
Manager:
Log & Lock
Mgr
Buffer
Manager
Access
Methods
Protocol
Layer
SNI
Data
File
T-
Log
Buffer Pool
- - - - - - - - -
Data Cache
- - - - - - - - -
Plan Cache
SQL Server
Network
Interface
TDS
Language
Event
SQL-
OS
INSERT,
UPDATE,
or
DELETE
?
Query
Tree
Query
Plan
OLE
DB
Data
Write ? Oooh! So dirty!
CheckPoint
Lazywriter
DD

11. Buffer
Pool
Ext’ns
Relational Engine
Optimizer
Query
Executor
Cmd Parser
Storage Engine
Trans-action
Manager:
Log & Lock
Mgr
Buffer
Manager
Access
Methods
Protocol
Layer
SNI
Data
File(s)
T-
Log
Buffer Pool
- - - - - - - - -
Data Cache
- - - - - - - - -
Plan Cache
SQL Server
Network
Interface
TDS
Language
Event
SQL
OS
?
Query
Tree
Query
Plan
OLE
DB
Data
Write ?
Check
Point
Lazywriter
Latches
Locks
HEKATON, A.K.A. IN-
MEMORY OLTP
bit.ly/1uLrXLN - Ovw
bit.ly/1u4nODQ - WP

12. SUMMARY