1. From Disk to Memory It’s 2016 Folks!
Phani Yenugu

2. About Me! Senior Enterprise Architect 23+ years in IT.
Worked with most of the OS/Server/Storage/Hardware technologies released since 1993.
First Oracle version 6.4 in 1995.
Exadata last 3+ years.
TOGAF 9 Enterprise Architect.
Certified Oracle 8i/9i/10g/11g DBA.
Certified Solaris System Admin.
Certified HP-UX System Admin.
Hobbies: Building/Breaking/Building(and learn), Robots, Rubik’s
Built digital Photo Frames before any major player in the market.

3. Disclaimer!
The opinions expressed on the following slides are solely mine.
Some comments/views may be dated due to version differences etc. Please contact vendor and their documentation.
Stunts performed by professional (me or my team) in closed course (sandbox) and real track (Production).
You can try in your closed course too!
Just be aware and understand thoroughly before you run/try/implement in your real track!

4. Why move to Memory?
Data Growth (More data means more ideas for business)
Business Complexity (More channels, integrations etc.)
Business is becoming more competitive. Users have no patience. So, time to Market is critical
Current data retrieval methods are dated!
Memory is cheap!

5. Oracle Architecture - SGA
Shared Pool
Java Pool
Buffer Cache
Large Pool
Give a brief overview of the presentation. Describe the major focus of the presentation and why it is important.
Introduce each of the major topics.
To provide a road map for the audience, you can repeat this Overview slide throughout the presentation, highlighting the particular topic you will discuss next.
Log Buffer
Streams Pool

6. Life of a SQL Statement
Give a brief overview of the presentation. Describe the major focus of the presentation and why it is important.
Introduce each of the major topics.
To provide a road map for the audience, you can repeat this Overview slide throughout the presentation, highlighting the particular topic you will discuss next.

7. Life of a SQL Statement
Give a brief overview of the presentation. Describe the major focus of the presentation and why it is important.
Introduce each of the major topics.
To provide a road map for the audience, you can repeat this Overview slide throughout the presentation, highlighting the particular topic you will discuss next.

8. Oracle Architecture – Buffer Cache
Dirty List
LRU List
Pinned Buffers
Dirty Buffers
Free Buffers

9. I/O Types:
Cached
Direct

10. Multi path Software etc.
I/O Layers
Direct I/O
(ASM)
Cached I/O
USER Layer
VFS Layer
FS CACHE
LVM Layer
SCSI/Fiber Layer
Multi path Software etc.
HDD Layer (SAN)

11. SAN Setup

12. Inside a SAN Frame

13. FS 1 4 2 5 3 6
RAID 0
Blocks Striped
DISK 1
DISK 2 1 4 2 5 3 6

14. FS 1 2
RAID 1
Blocks Mirrored 3
DISK 1
DISK 2 1 1 2 2 3 3

15. RAID 5 Blocks Striped and Mirrored 1 4 2 5 3 6 1 2 P 3 P 4 P 5 6 FS
DISK 1
DISK 2
DISK 3 1 2 P 3 P 4 P 5 6

16. RAID 5 is Good…..or is it?

17. RAID 5
Great for Reads
But, double penalty for writes
Risk of data loss if there are 2 bad blocks in 2 drives.

18. RAID 10 Blocks Mirrored and Striped 1 4 2 5 3 6 1 1 2 2 3 3 4 4 5 5 6FS 1 4 2 5 3 6
RAID 10
Blocks Mirrored
and Striped
DISK 1
DISK 2
DISK 3
DISK 4 1 1 2 2 3 3 4 4 5 5 6 6

19. What is a block?
Block sizes
Linux (64bit) – 4k
Oracle – 8k (standard)
Data is retrieved in blocks. It may contain one or more rows
Entire row (or rows) is sent back to buffer cache

20. Oracle Architecture – Buffer Cache
Dirty List
LRU List
Pinned Buffers
Dirty Buffers
Free Buffers

21. In-Memory
In-Memory builds columnar structure. Possible to specify only the columns that are of interest

22. If there are DML changes they are reflected in In-Memory
No logging, so little overhead
Quick scale-up and scale-out
* Not persistent. DB recycle will lose the in-memory data.

23. In-Memory pools IMCU - In Memory Compression Unit
SMU - Snapshot Metadata Unit

24. In-Memory views v$im_segments # objects that are in memory
v$inmemory_area
Allocation of IMCUs and SMUs (80/20)
v$im_header
# of rows in each IMCU

25. How to enable Run im_advisor Add memory to SGA
Configure inmemory_size (min. 100MB)
Place tables in Memory
(alter table <table_name> inmemory;) <options>

26. Recap Easy to implement. No application changes Low overhead
Easy scale-up and scale-out
Best ROI
Fast & Efficient
Business value

27. I don’t have license(…neither budget)
Cannot be as effective but….
Get more memory (it’s cheap)
Pin objects (db_cache_keep_size)
Tune queries better (of course)
Full Database Caching (12c)
(alter database force full database caching;)

28. and one more….

29. Do you know? Redolog and Control file Block Size in Oracle
has always been 512 bytes. Even in 12c!

30. Check for yourself  SYS> select distinct blocksize from v$log;
512
Controlfile logblock size
SYS> select max(lebsz) from sys.x$kccle;
MAX(LEBSZ)

31. If you notice
Controlfile Enqueue or
Logfile Sync
waits in your database

32. Make sure
FS is NOT RAID 5
SAN Cache is NOT FULL
Move to Direct I/O (ASM)
Move to a FS with 512 Blocksize

33. THANK YOU!