# Performance suggestions or best practices ideas?

**URL:** <https://www.ruby-forum.com/t/performance-suggestions-or-best-practices-ideas/59270>\
**Category:** Rails\
**Created:** [May 3, 2006, 12:49am UTC](https://www.ruby-forum.com/t/performance-suggestions-or-best-practices-ideas/59270 "2006-05-03T00:49:44Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![mlopke](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/9de053/32.png) [@mlopke](https://www.ruby-forum.com/u/mlopke)\
**Post date:** [May 3, 2006, 12:49am UTC](https://www.ruby-forum.com/t/performance-suggestions-or-best-practices-ideas/59270/1 "2006-05-03T00:49:44Z")

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Any suggestions on applications that involve alot of calcualtions on a  
fairly large data set?

My app uses a set of raw data ~5k, applies some default/override rules  
on the raw data and does some calculations on the data in combination  
with a list of assumptions. A ranked list along with detailed metrics  
is generated. The end user can manipulate some of the rules and  
assumptions to generate different metrics for comparison.

My current approach maintains the original data set, default/overrides  
and assumptions as seperate models and does all the ranking calculations  
on the fly. The performance is a bit sluggish if I’m looking at  
more that 400 objects and this is with only one user.

Any suggestions on caching options to explore? Should I consider using  
a seperate model for storing the results? This would make the ranking  
and comparisons quicker, but I’m concerned about the overhead of having  
to write large amount of temporary data to the database.

Thanks,  
Mike

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**Author:** ![mlopke](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/9de053/32.png) [@mlopke](https://www.ruby-forum.com/u/mlopke)\
**Post date:** [May 3, 2006, 8:36pm UTC](https://www.ruby-forum.com/t/performance-suggestions-or-best-practices-ideas/59270/2 "2006-05-03T20:36:05Z")

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The app looks at potential investments. Raw data is 5K rows of mixed  
info. ( numbers, categories, dates, etc. )

The calculations are on par with Excel. I don’t think there is alot of  
room for improvement on the calculation algorithm. I was looking for a  
way to avoid the expense of recalculating the same set of metrics. The  
end user goes through these steps:

1. Set initial query paramters ( $to invest, investment type, etc. )
2. App gets raw data, combines with overrides/defaults/assumptions &  
does metrics calculation to generate ranked results
3. User looks at ranked results
4. User looks at details for particular investment
5. User returns to ranked results to investigate other opportunities  
…

I wanted to cache the ranked results rather than have to regenerate it  
each time I return to the list. Is there a way to have a persistant  
object in memory or is my only option to write the data to a table. A  
new ranked results would be generated for each new initial query mod or  
a change in the overrides/defaults/assumptions.

Thanks,  
Mike

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<div class="post-metadata">

**Author:** ![mlopke](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/9de053/32.png) [@mlopke](https://www.ruby-forum.com/u/mlopke)\
**Post date:** [May 3, 2006, 7:06pm UTC](https://www.ruby-forum.com/t/performance-suggestions-or-best-practices-ideas/59270/3 "2006-05-03T19:06:32Z")

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Could you do similar calculations in, say, Microsoft Excel? How does the  
performance of your application compare with that of Excel? If Excel is  
a _lot_ faster, I’d say go hunting for tuning opportunities. But if  
they’re comparable, and scale roughly the same way with increasing  
problem size, you’re probably not going to be able to squeeze much  
performance out without a better algorithm.

What sort of calculations are they? What is the 5K … numbers, rows of  
a database table …??

Mike L. wrote:

> and assumptions as seperate models and does all the ranking calculations

–  
M. Edward (Ed) Borasky

> **[世界杯竞猜彩票-世界杯官网竞猜（集团）有限公司](http://www.linuxcapacityplanning.com/)**
>
> 世界杯竞猜彩票一直以来遵守商业道德，世界杯官网竞猜坚持诚信为本，保证诚实经营。世界杯竞猜彩票先后成为安徽省电子商务协会理事单位、安徽省网商协会会员单位、合肥市电子商务协会理事单位、合肥市服务外包行业协会会员单位、安徽省云计算产业促进会会员单位。世界杯官网竞猜一直保持良好的技术及服务态度，更好地为客户服务。

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<div class="post-metadata">

**Author:** ![mlopke](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/9de053/32.png) [@mlopke](https://www.ruby-forum.com/u/mlopke)\
**Post date:** [May 3, 2006, 9:48pm UTC](https://www.ruby-forum.com/t/performance-suggestions-or-best-practices-ideas/59270/4 "2006-05-03T21:48:24Z")

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On 5/3/06, Mike L. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> Is there a way to have a persistant  
> object in memory or is my only option to write the data to a table.

You could store an array of the ranking scores and id’s of the  
investment options in the session[] object. That way they would  
persist between pages.

- Isaac

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<div class="post-metadata">

**Author:** ![mlopke](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/9de053/32.png) [@mlopke](https://www.ruby-forum.com/u/mlopke)\
**Post date:** [May 3, 2006, 11:37pm UTC](https://www.ruby-forum.com/t/performance-suggestions-or-best-practices-ideas/59270/5 "2006-05-03T23:37:53Z")

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On May 3, 2006, at 1:22 PM, Mike L. wrote:

> tried storing this in the session but I don’t really know.
> 
> Mike

```
For something like this you might want to look at memcached and Eric

```

Hodels CachedModel extension.

> **[dev.robotcoop.com](https://www.robotcoop.com/dev-sub/index.html)**
>
> Tools and projects used by The Robot Co-op, Inc.

```
Or you can setup a small drb server to hold this info and stored and

```

retrieve the results.

Cheers-  
-Ezra

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<div class="post-metadata">

**Author:** ![mlopke](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/9de053/32.png) [@mlopke](https://www.ruby-forum.com/u/mlopke)\
**Post date:** [May 3, 2006, 10:22pm UTC](https://www.ruby-forum.com/t/performance-suggestions-or-best-practices-ideas/59270/6 "2006-05-03T22:22:41Z")

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Isaac R. wrote:

> On 5/3/06, Mike L. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:
> 
> > Is there a way to have a persistant  
> > object in memory or is my only option to write the data to a table.
> 
> You could store an array of the ranking scores and id’s of the  
> investment options in the session[] object. That way they would  
> persist between pages.
> 
> - Isaac

Thanks.

I’ve considered using the session[] object. This, however, brings up an  
interesting question. What is the practical limit on what can be stored  
in it? Lets say I have 500 investments I’m considering and each has 20  
metrics I’ve calculated. My hunch is that it would cause problems if I  
tried storing this in the session but I don’t really know.

Mike

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<div class="post-metadata">

**Author:** ![mlopke](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/9de053/32.png) [@mlopke](https://www.ruby-forum.com/u/mlopke)\
**Post date:** [May 5, 2006, 11:54pm UTC](https://www.ruby-forum.com/t/performance-suggestions-or-best-practices-ideas/59270/7 "2006-05-05T23:54:46Z")

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> For something like this you might want to look at memcached and Eric  
> Hodels CachedModel extension.
> 
> [http://dev.robotcoop.com/Libraries/cached\_model/files/README.html](http://dev.robotcoop.com/Libraries/cached_model/files/README.html)
> 
> Or you can setup a small drb server to hold this info and stored and  
> retrieve the results.
> 
> Cheers-  
> -Ezra

Thanks. I’ll give it a look.