Evaluate() slows processing?

[Glowball]

This is largely a question for tleish, is it true that the Evaluate() function slows things down? I use it because sometimes it seems that CF will toss out errors with simple math if I don't use it. I tend to slap it around all of my math so this is raising a flag with me. Is there something I should read about Evaluate()?

Thanks!

 

[tleish]

Don't get me wrong, there are sometimes you can't avoid using the Evaluate() function... and I only use it after exhausting all other possibilites. I can't reference anywhere in particular, but I've read several articles that talk about Evaluate() being one of the slowest functions in ColdFusion. I would use Val() for math functions in place of Evaluate... but even then, I would avoid using Val() also.

Don't take my word for it, try this bit of code below that shows the different speed of Normal, Val(), and Evalute() functions.

[COLOR=666666]<!--- If you change this from 100 to 500,
it will break Evaluate() --->[/color]
<CFSET vLoop = 500>

[COLOR=666666]<!--- Test Normal Speed --->[/color]
[COLOR=000080]<B>[/color]Normal:[COLOR=000080]</B>[/color][COLOR=000080]<BR>[/color]
<CFSET vNumber = 1>
<CFSET start = GetTickCount()>
<CFLOOP FROM=&quot;1&quot; TO=&quot;#VARIABLES.vLoop#&quot; INDEX=&quot;i&quot;>
<CFSET vNumber = VARIABLES.vNumber * i>
</CFLOOP>
<CFSET end = GetTickCount()>
<CFSET time = VARIABLES.end - VARIABLES.start>
<CFOUTPUT>
#VARIABLES.time# milliseconds[COLOR=000080]<BR>[/color]
vNumber=#VARIABLES.vNumber#
</CFOUTPUT>
[COLOR=000080]<BR>[/color]
[COLOR=000080]<BR>[/color]

[COLOR=666666]<!--- Test the speed of Val() --->[/color]
[COLOR=000080]<B>[/color]Val():[COLOR=000080]</B>[/color][COLOR=000080]<BR>[/color]
<CFSET vNumber = 1>
<CFSET start = GetTickCount()>
<CFLOOP FROM=&quot;1&quot; TO=&quot;#VARIABLES.vLoop#&quot; INDEX=&quot;i&quot;>
<CFSET vNumber = Val(VARIABLES.vNumber * i)>
</CFLOOP>
<CFSET end = GetTickCount()>
<CFSET time = VARIABLES.end - VARIABLES.start>
<CFOUTPUT>
#VARIABLES.time# milliseconds[COLOR=000080]<BR>[/color]
vNumber=#VARIABLES.vNumber#
</CFOUTPUT>
[COLOR=000080]<BR>[/color]
[COLOR=000080]<BR>[/color]

[COLOR=666666]<!--- Test speed of Evaluate() --->[/color]
[COLOR=000080]<B>[/color]Evaluate():[COLOR=000080]</B>[/color][COLOR=000080]<BR>[/color]
<CFSET vNumber = 1>
<CFSET start = GetTickCount()>
<CFLOOP FROM=&quot;1&quot; TO=&quot;#VARIABLES.vLoop#&quot; INDEX=&quot;i&quot;>
<CFSET vNumber = Evaluate(VARIABLES.vNumber * i)>
</CFLOOP>
<CFSET end = GetTickCount()>
<CFSET time = VARIABLES.end - VARIABLES.start>
<CFOUTPUT>
#VARIABLES.time# milliseconds[COLOR=000080]<BR>[/color]
vNumber=#VARIABLES.vNumber#
</CFOUTPUT>

On my machine, I average the following output:

Normal:
20 milliseconds
vNumber=7.3621402796E+127

Val():
60 milliseconds
vNumber=7.3621402797E+127

Evaluate():
120 milliseconds
vNumber=7.3621402797E+127 - tleish

 

[Glowball]

Interesting, thanks for taking the time to work that out. I use Evaluate() a LOT so this will be something I'll need to implement over time -- fixing things, I mean. I'm wondering what would be slower though, because now I feel like I'll need to do this:

<cftry>
<cfset someVar = VARIABLES.something + VARIABLES.somethingelse>
<cfcatch>
    <cfset someVar = Evaluate(VARIABLES.something + VARIABLES.somethingelse>
</cfcatch>
</cftry>

I'm guessing that one will be slower whether it works or not, yes? Hmm, a dilemma... because Evaluate() always works and sometimes normal math won't for some mysterious reason.

Any thoughts on that?