Forum Discussion
Andy_Herrman_22
Nimbostratus
NimbostratusLocal 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...
Mike_62629Nimbostratus
NimbostratusPosted By Colin on 07/18/2007 2:50 PM
The reason it's faster to us HTTP::uri later on is because this value is already cached. You're not performing another lookup, the data has been cached via TMM, and is available to the iRules interpreter as necessary. So all you're doing is pointing to that value in memory, not performing a lookup.
This means that setting your initial variables "fulluri" and "host" is not necessary. As a matter of fact, NOT setting them, and just using HTTP::uri and HTTP::host respectively is technically a performance gain.
HTH,
Colin
Sorry to dredge up such an old thread, but I was wondering if this was also the case for other F5 internal vars, like
[HTTP::cookie xyz]
