Re: [Semediawiki-user] Performance of "#if:" vs. intro= default=

[Alex M. H. <amh...@on...>]

John and Yaron,

It sounds like there is some consensus that performance will likely not be  
an issue, so I think I'll used intro/default when I can--it is much easier  
to read the markup--and use #if when intro/default cannot handle the job.

Thanks for your input and advice,
Alex
--
Alex M. Hendler
ontolawgy(tm) LLC
http://ontolawgy.com
------- Original message -------
From: "Yaron Koren" <ya...@gm...>
To: "John Arrowwood" <Jo...@ir...>
Cc: amh...@on..., "sem...@li..."  
<sem...@li...>
Subject: Re: [Semediawiki-user] Performance of "#if:" vs. intro= default=
Date: Monday, August 9, 2010 15:57:49 GMT+03:00

> Hi,
>
> I don't think #if results in its contents being called twice. I have no  
> idea
> which approach would have the better performance, though - my guess is  
> that
> the impact on performance either way would be small.
>
> -Yaron
>
> On Sun, Aug 8, 2010 at 6:42 PM, John Arrowwood <Jo...@ir...> wrote:
>
>> While I haven't looked at the code to be sure, I'd say that there is  
>> about
>> a
>> 99.9% chance that using the #if results in the query being run twice.   
>> On
>> the bright side, MySQL probably cached it, so the second one is probably
>> faster than it otherwise might be.
>>
>> However, in general, it is bad practice to do the #if approach for  
>> reasons
>> that have nothing to do with speed.  So my advice would be: don't do  
>> that.
>>
>> On Sun, Aug 8, 2010 at 10:05 AM, Alex M. Hendler
>> <amh...@on...>wrote:
>>
>> > Hi,
>> >
>> > A few quick questions for the list:
>> >
>> > Is there any performance difference between using an #if: parser  
>> function
>> > to determine if a query would have output and then running the query  
>> as
>> > compared to using the built-in "intro" and "default" inline query
>> > parameters?
>> >
>> > For example:
>> >
>> > Is this:
>> >
>> > {{#if: {{#ask: [[some property::{{PAGENAME}}]]}}|
>> > ==Some Property==
>> > {{#ask: [[some property::{{PAGENAME}}
>> > |?Some other property
>> > }}|''There is no "some property" value for {{PAGENAME}}'', but see
>> {{#ask:
>> > [[Some other property::{{PAGENAME}}]]}}}}
>> >
>> > substantially slower than this?
>> >
>> > {{#ask: [[some property::{{PAGENAME}}]]
>> > |?Some other property
>> > |intro=<h2>Some Property</h2>
>> > |default=''There is no "some property" value for {{PAGENAME}}'', but  
>> see
>> > {{#ask: [[Some other property::{{PAGENAME}}]]}}
>> > }}
>> >
>> > I have not noticed any performance difference on a small test system,  
>> but
>> > I am wondering how it would scale. My concern is this: If there is a
>> query
>> > result, does the #if: function is run the query twice (once to check  
>> if
>> > the condition can be satisfied, and again to show the output)? If so,
>> does
>> > the intro/default method run the query only once in every case? (Or is
>> the
>> > converse true, or am I just completely wrong?)
>> >
>> > Any insight/feedback would be very much appreciated.
>> >
>> > Thanks,
>> > Alex
>> > --
>> > Alex M. Hendler
>> > ontolawgy(tm) LLC
>> > http://ontolawgy.com
>> >
>> >
>> >
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>>
>>
>> --
>> John Arrowwood
>> John (at) Irie (dash) Inc (dot) com
>> John (at) Arrowwood Photography (dot) com
>> John (at) Hanlons Razor (dot) com
>> --
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>> http://arrowwood.blogspot.com/
>>
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