MagmaCollectionReader>>size takea a long time

[Chris Muller]

Hi Juan,

> "MagmaCollectionReader>>size  first evaluation"
> [ ((magmaSession root at: #ThesaurusTerm) read: #issnString) size ]
> timeToRun "answer about   16771 milliseconds"

It turns out #size is generic for any kind of query expression; but
for up-to single-clause queries, it should check for that so it can be
instantaneous as you point out.

I'll make a note of this and see about enhancing it for r41; but it
might be a while before r41 is out (given that r40 isn't even out
yet!).

#lastKnownSize; caches the size in the Reader instance, so subsequent
calls are instantaneous even for complex queries.

 - Chris


On 9/3/07, Burella Juan M. <juan.burella at gmail.com> wrote:
> Chris thanks for your answers. Yes, I was using the release 39. I´ve tested
> it with r40 (r40Gamma3) and it worked better.
> I tested this with a bigger collection (84661 objects ) and it takes 16
> seconds to answer either #size and #lastKnownSize. Do I have to set
> something to enable #lastKnownSize caching?
>
> The new results are:
>
>
> "------------ 84661 objects - MagmaCollection>>size - fiirst evaluation"
> [ (magmaSession root at: #ThesaurusTerm) size ] timeToRun  "answer about
> 247 milliseconds"
> "Note: magmaSession root at: #ThesaurusTerm answer a MagmaCollection"
>
>
> "second evaluation"
> [ (magmaSession root at: #ThesaurusTerm) size ] timeToRun  "answer about 0
> milliseconds"
>
> "MagmaCollectionReader>>size  first evaluation"
> [ ((magmaSession root at: #ThesaurusTerm) read: #issnString) size ]
> timeToRun "answer about   16771 milliseconds"
>
> "second evaluation"
> [ ((magmaSession root at: #ThesaurusTerm) read: #issnString) size ]
> timeToRun "answer about    16870 milliseconds"
>
>
> "MagmaCollectionReader>>size  first evaluation"
> [ ((magmaSession root at: #ThesaurusTerm) read: #issnString) lastKnownSize]
> timeToRun "answer about    16573 milliseconds"
>
> "second evaluation"
> [ ((magmaSession root at: #ThesaurusTerm) read: #issnString) lastKnownSize]
> timeToRun "answer about     16529 milliseconds"
>
>
>
> "------- 5500 objects - MagmaCollection>>size - fiirst evaluation"
> [ (magmaSession root at: #Serial) size ] timeToRun  "answer about 698
> milliseconds"
> "Note: magmaSession root at: #Serial answer a MagmaCollection"
>
>
> "second evaluation"
> [ (magmaSession root at: #Serial) size ] timeToRun  "answer about 0
> milliseconds"
>
> "MagmaCollectionReader>>size  first evaluation"
> [ ((magmaSession root at: #Serial) read: #issnString) size ] timeToRun
> "answer about  1246 milliseconds"
>
> "second evaluation"
> [ ((magmaSession root at: #Serial) read: #issnString) size ] timeToRun
> "answer about   1246 milliseconds"
> Juan M.
>
>
>
> On 8/31/07, Chris Muller <asqueaker at gmail.com > wrote:
> > Juan, please the section "Optimizing Performance" in the documentation
> > about querying MagmaCollections to understand when #size will be very
> > fast vs. pretty slow.
> >
> > http://wiki.squeak.org/squeak/5859
> >
> > For the cases that are "pretty slow" ( i.e., a Reader requiring
> > distinct results), note you have #lastKnownSize, which is the cached
> > size (therefore instant access).
> >
> > - Chris
> >
>
>
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