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Database Change Notifications:
Primitives for Efficient Database
Query Result Caching
Cesar Galindo-Legaria, Torsten Grabs,
Christian Kleinerman, Florian Waas
SQL Server Engine
Microsoft Corp.
Redmond, WA
USA
VLDB 2005, Trondheim, Norway
http://www.microsoft.com/sql/2005/
Motivation
Clients
HTTP
HTTP
HTTP
Mid-tier cache:
Web server
farm
SELECT price
FROM books
WHERE title = ‘T-SQL’
DBS
Title
Price
T-SQL
Title
10.00
Price
T-SQL
20.00
10.00
HTTP
15.00
UPDATE books
SET price = 20.00
WHERE title = ‘T-SQL’
• Three-tier architecture for web applications
• Time-to-life based approaches for caching of read-mostly
dynamic results at mid-tier for performance reasons
• Problem: Outdated results in case of database updates
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Demo Highlights
Clients
HTTP
Mid-tier cache:
Web Query
server Plan
farm
Title
Price
T-SQL
10.00
20.00
SELECT
Update Plan
DBS
Title
Price
T-SQL
20.00
10.00
HTTP
15.00
Change Notification:
- cache re-run query, or
- send delta
UPDATE
• “Non-materialized” indexed view for change detection
– Query plan rewrite to register cached query results
– Update rewrite to notify caches of changes in case of nonempty materialized view maintenance delta stream
– Note: No DBMS installation necessary at the mid tier
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? Questions ?
Come and see the
Demo!!!
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