The Ebay Matrix: Defining an Enterprise Architecture that Scales Across the Globe

1
The Ebay Matrix Defining an Enterprise
Architecture that Scales Across the Globe

• Ian Flint (Ebay)
• Notes taken by Wei Xu

2
Ebay v1

• Perl
• 1995
• Scales upto 50k hits per day
• Not bad in 1995

3
Ebay v2

• 97-99
• C Oracle on Solaris

4
V2.1

• Servers grouped into pools
• Front-end load balancing
• Separate search from other transactional databases

5
V2.3

• 1999
• Massively scaling the database
• Move CPU intensive work to applications
• Foreign keys, joins, sorting
• Minimize Transactions
• No business logics in database
• Single database

6
V2.4

• 99-01
• Split Database
• Windows NT IIS C front end
• Solaris Oracle

7
V2.5

• Horizontal Database Scaling
• CATY databases
• Manually partition databases based on categories
  of listing
• Also account database etc.
• Logical database host
• Separate application db notion from physical
  implementation
• 170 database servers nowadays

8
Scalability in Development Process

• 3.3 millions of lines of legacy C code
• Cyclomatic complexity 800(!)
• a broad measure of soundness and confidence for a
  program.
• Hitting compiler limits on of methods per class

9
V3

• Java
• Stateless application tier
• Avoid HTTP Sessions
• Sticky servers make it hard to load balance
• Use cookies
• Servlet based framework running in web container
• Minimize transactions
• Avoid locking data rows
• Extensive component reuse

10
Secret Sauce

• EBay data access layer
• Partitioning
• Logical data access
• Replication
• Control always consider what to do when logical
  data source went down (in all apps)
• Graceful degradation (app specific)
• Vertical scaling
• Connection pooling
• JDBC prepared statements

11
Multiple apps share some infrastructure

• Batch
• Web
• Static page
• HTML
• Images (1 billion per day)
• API
• Share the same business/ integration tier
  components

12
V4 ( in planning )

• Pure java presentation layer
• Whole page in java (instead of XSLT)
• Everything in java DOM tree directly to HTML
• More generic components on the page