The AskTOM Archive - selected presentations from Tom Kyte from Oracle Corporation 2010-2015.

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Why Engineered Systems
Last updated – Dec 11, 2012
Thomas Kyte
http://asktom.oracle.com/

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In a Warehouse
environment – how many
DBA’s can tell you how
many GB’s/sec they can
transfer from disk to
server?

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In an OLTP environment,
what would happen if log
writes on a busy system
went from an average of 3-
5ms to 7-10ms (or longer)?

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Puzzle Pieces to be integrated, vs Engineered System

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Getting cross domain expertise to work together…

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Patches to be applied to stay current…

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Exadata Engineered System Transformation
 Hundreds of engineer years spent optimizing and
hardening the system end-to-end
– Frees I/T talent to focus on business needs
 Standard platform improves support experience
 Runs all existing Oracle Database workloads
 Building block of the Oracle Cloud
Less Risk, Better Results

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Exadata is Smart Storage
 Database Servers
– Perform complex database processing such as
joins, aggregation, etc.
 Exadata Storage Servers
– Storage Server is smart storage, not a DB node
– Search tables and indexes filtering out data that is
not relevant to a query
– Cells serve data to multiple databases enabling
OLTP and consolidation
– Simplicity, and robustness of storage appliance
Compute and Memory
Intensive Processing
Data Intensive
Processing

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Simple Query Example
Select sum (sales)
where Date=‘24-Sept’
Optimizer Chooses
Partitions & Indexes
to Access
• Scan compressed blocks in
partitions / indexes
• Retrieve sales amounts for
Sept 24
• 10 TB scanned
• 1 GB returned
to servers
What were
my sales
yesterday?
Oracle DB
Grid
Exadata
Storage
Grid

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Exadata Intelligent Storage
 Exadata storage servers also run more complex
operations in storage
– Join filtering
– Incremental backup filtering
– I/O prioritization
– Storage Indexing
– Database level security
– Offloaded scans on encrypted data
– Data Mining Model Scoring
 10x reduction in data sent to DB servers
is common
Exadata Intelligent
Storage Grid

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Exadata Storage Index
Transparent I/O Elimination with No Overhead
• Exadata Storage Indexes maintain summary
information about table data in memory
• Store MIN and MAX values of columns
• Typically one index entry for every MB of disk
• Eliminates disk I/Os if MIN and MAX can never
match “where” clause of a query
• Completely automatic and transparent
A B C D
1
3
5
5
8
3
Min B = 1
Max B =5
Table Index
Min B = 3
Max B =8
Select * from Table where B<2 - Only first set of rows can match

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Exadata Hybrid Columnar Compression
Highest Capacity, Lowest Cost
• Data is organized and compressed by column
• Dramatically better compression
• Speed Optimized Query Mode for Data
Warehousing
• 10X compression typical
• Runs faster because of Exadata offload!
• Space Optimized Archival Mode for
infrequently accessed data
• 15X to 50X compression typical
Query
Faster and Simpler
Backup, DR, Caching,
Reorg, Clone Benefits Multiply

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Compression Ratio of Real-World Data
• Compression Ratio varies by
customer and table
• Trials were run on largest table
at 10 ultra large companies
• Average revenue > $60 BB
• Average Query Compression
ratio was 13x
• On top of Oracle’s already
highly efficient format

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Exadata X3 Database In-Memory Machine
 X3 mass memory hierarchy delivers extreme performance
– Automatically moves all active data from disk to memory
 DRAM memory expanded to 2 or 4 TB for hottest data
– 4 to 40 TB of compressed user data
 Flash memory expanded 4X to 22 TB per rack
– 40 to 200 TB of compressed user data – ALL active data
– 1.5 Million SQL random read I/Os per second for OLTP
 Comparable to 15,000 disk drives in 150 array frames
– 100 GB/sec SQL data scan rate for reporting and warehouses
 Comparable to 1,000 disk drives in 10 array frames
500 TB
DISK
22 TB PCI
FLASH
2 or 4 TB
DRAM
Cold Data
Hottest Data
Active Data

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Exadata Smart Flash Cache Write-Back
 Caches Write I/Os in PCI flash in addition to Read I/Os
 Transparently accelerates write intensive workloads
– 20X more write IOPS than disk on X3
– 10X more write IOPs than disk on V2 and X2
 Persistent write cache speeds database recovery
 Exadata Flash Cache is much more effective than flash
tiering architectures used by others
– Caches current hot data, not yesterday’s
– Caches data in granules 8x to 16x smaller than tiering
 Greatly improves the effectiveness of flash
Writes I/Os
1 Million 8K
Write IOPs
from SQL
New

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Exadata Smart Flash Log
 Accelerate Transaction Response Times Using Flash
 Uses Flash for Database Logs in a clever way
– Flash is fast but has slow outliers
 Smart Flash Log feature transparently uses Flash as a parallel write
cache to disk controller cache
– Whichever write completes first wins (disk or flash)
 Better response time and more throughput
 Uses almost no flash capacity (0.1% of capacity)
Default (on left)
- Choppy Response
- High Outliers
Smart Flash Log
- 3x faster response
- Much lower outliers
Transaction
Response Times
Smart Flash Log Enabled
Automatic and
Transparent
‒ Erase cycles, wear leveling, etc

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Exadata I/O Resource Management
Mixed Workloads and Multi-Database Environment
• Ensure different databases are allocated the
correct relative amount of I/O bandwidth
• Database A: 33% I/O resources
• Database B: 67% I/O resources
• Ensure different users and tasks within a
database are allocated the correct relative
amount of I/O bandwidth
• Database A:
• Reporting: 60% of I/O resources
• ETL: 40% of I/O resources
• Database B:
• Interactive: 30% of I/O resources
• Batch: 70% of I/O resources
Exadata Cell
InfiniBand Switch/Network
Database A Database B
Exadata Cell Exadata Cell

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Exadata Database Cloud
• Exadata has the unique ability to run many databases
supporting multiple workloads in a single cloud platform
– High-end OLTP, Warehousing, batch, reporting, backups, …
– All at the same time
• X3 database in-memory delivers extreme performance for
all workloads
– Also prevents one workload from overloading disks leading
to poor performance for allAll Workloads, All Applications
SAP, Siebel, PeopleSoft, JDE,
E-business Suite, Fusion
Applications

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Exadata Unified Workload Transformation
Single Machine for…
• Data Warehousing
• OLTP
• Database Cloud
OLTP with Analytics and
Parallelism of Warehousing
Warehousing with Interactivity,
Availability, and Security of OLTP

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