Transcript Speaker Kick Off Meeing

DEV414 Black-belt
ASP.NET
Tips And Tricks For Your
ASP.NET Applications
Rob Howard
Program Manager
Web Platform and Tools Team
ASP.NET Community
Contact
[email protected]
http://weblogs.asp.net/rhoward
ASP.NET Resources
http://www.asp.net/forums
http://www.asp.net/whidbey
http://www.asp.net/roadshow
Agenda
Building an intermediate page
Set focus
Outputcache (duration and page size)
Per-request caching
Reflection caching
Returning multiple result sets
SQL record paging
Background processing
Database cache invalidation
Intermediate Page
Problem
Long running, expensive operation
Prevent Refresh or Re-Submit
Display temporary ‘processing’ UI
Client is still waiting for work to complete
Server is still processing
Perception …is not reality
Client is re-activated
Multiple techniques, client script easiest
Intermediate Page
Set Focus
Problem
Large HTML Form
Set initial focus of the Form, e.g. Button
Enable dynamic control selection
JavaScript focus() method
Use ClientID of Server Control
Page.RegisterStartupScript()
Script that runs when page starts
Set Focus
Duration And Page Size
Problem
How much data to return
How large should page be
Page size does affect performance
Larger pages slow down server
Aim for ~30K (Google is ~2K!)
Duration for OutputCache
More tunable than most people think
Even 1Sec duration makes a difference
Page Size And Duration
Per-Request Caching
Problem
Data that cannot be cached
Result is unique on each request
Per-Request Caching
Cache data for the life of a request
Different than Cache API
Use HttpContext.Items
HttpContext is scoped to request
Destroyed when request completes
Per-Request Caching
Reflection Caching
Problem
Reflection is powerful, but expensive
3-4 times cost of normal object creation
Dynamic Class Loading
Inspect or load classes at runtime
Used by new Provider pattern
Cache the constructor of the class
1/3 Cost of non-Cached
Technique used in Forums Provider
Reflection Caching
Multiple Result Sets
Problem
Database operations are expensive
Network IO is very costly
Be as efficient as possible
Use SPROCs or Parameterized SQL
Batch Result Sets
SqlDataReader.NextResult()
Not as evident on local SQL (no network)
Batched Result Set
SQL Record Paging
Problem
DataGrid paging requests all records
Only shows requested, discards others
Return only the data you need
Reduces time spent with DB
Increases application throughput
Stored Procedure paging
Uses temporary table
Requires knowledge of SQL indexes
Paging Data In SQL Server
Background Threading
Problem
Expensive work (index, email, updates …)
Optimize the request path
Schedule other tasks
Use System.Threading.Timer
Callback activates every n milliseconds
Requires CLR AppDomain to be active
Can get HttpContext – few tricks
Uses thread from threadpool
Background Threading
DB Cache Invalidation
Problem
Keeping Cache and Database in sync
Cache for period of time
Optimally invalidate on data changes
Built-in feature of ASP.NET 2.0
Several bad techniques for ASP.NET 1.X
Uses background thread
Poll for database changes
Similar model used in ASP.NET 2.0
Database Cache Invalidation
Summary
Tips and Tricks to make your app better
Tune and optimize your application
Control data from the database
Off-load work
Cache as much as possible
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This presentation is for informational purposes only. Microsoft makes no warranties, express or implied, in this summary.