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Andy_Herrman_22's avatar
Andy_Herrman_22
Icon for Nimbostratus rankNimbostratus
Jul 16, 2007

Local var performance

Quick performance question. I'm looking back at the iRules I worked on a year ago for our F5 evaluation and noticed something odd. At the top of the iRule the URI and Host values are stored in varia...
application delivery
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hoolio's avatar
hoolio
Icon for Cirrostratus rankCirrostratus
May 20, 2008
A quick way to verify whether a command is cached or not is to log the current value, change it and then try to log it again. If the same value is logged the second time, then the command output is cached. This caching seems to only be maintained in the same event in the same priority. I think (almost?) all of the HTTP:: commands are cached. Maybe someone with definitive knowledge could add more detail (Click here)? 

 
 when HTTP_REQUEST { 
    log local0. "\[HTTP::uri\]: [HTTP::uri]" 
    HTTP::uri "/modified" 
    log local0. "\[HTTP::uri\]: [HTTP::uri]" 
  
    log local0. "\[HTTP::cookie value test_cookie\]: [HTTP::cookie value test_cookie]" 
    HTTP::cookie test_cookie "modified" 
    log local0. "after modification: \[HTTP::cookie value test_cookie\]: [HTTP::cookie value test_cookie]" 
 } 
 when HTTP_REQUEST priority 501 { 
    log local0. "priority 501 \[HTTP::uri\]: [HTTP::uri]" 
    log local0. "priority 501 \[HTTP::cookie value test_cookie\]: [HTTP::cookie value test_cookie]" 
 }

: [HTTP::uri]: /test

: after modification: [HTTP::uri]: /test

: [HTTP::cookie value test_cookie]: test_value

: after modification: [HTTP::cookie value test_cookie]: test_value

: priority 501 [HTTP::uri]: /modified

: priority 501 [HTTP::cookie value test_cookie]: modified

Aaron