[Glass] Can I avoid ReversedRangeIndexReadStream >> atEnd ?

[Mariano Martinez Peck via Glass]

On Wed, Oct 25, 2017 at 3:07 PM, Dale Henrichs via Glass <
glass at lists.gemtalksystems.com> wrote:

> Mariano,
>
> The costly code is in RangeIndexReadStream>>_atEndForStream: (when aBool
> is true) and that code can be safely skipped if the values in the index
> will not include nils, or if your index is on a CharacterCollection and you
> do not mix Strings and Symbols or if your index is on a Float and the
> values do not include NaNs.
>
>
Hi Dale,

In my case, the collection is of instances of FaSecurityClosingPriceRecord
and as you can see in my original email the index is on a date type of
instVar.
If you see code below:

             query := self
                nearestQueryFor: dateToCompare
                on: (self indexingDict at: securityUniqueId).
              stream := query reversedReadStream.
              ^ (stream _atEndForStream: false)
                ifTrue: [ nil ]
                ifFalse: [ stream getNext ]


I can assure you that:

1) Values of the indexes are always dates.
2) I have no FaSecurityClosingPriceRecord instance with nil date
3) I have no nil in the collection passed by to `nearestQueryFor:
dateToCompare  on:`

Yet....I am getting different results wether I pass `false` or `true` to
#_atEndForStream:   :(
And even worst, it looks like the correct one is when I pass false...

Maybe I am hitting an scenario where `true` is needed that is not in the
ones you listed?
I can confirm at least that the speedup when using `false` was huge, so I
would love to find a way to skip that!

Thanks in advance,


In 3.4 we do this automatically when you create a btree plus index with
> optmiizedComparison index option ... the 3.4 stream operations have been
> optimized in other ways as well --- 3.4 is due to be released very soon ...
>
> Dale
>
> On 10/25/2017 07:01 AM, Mariano Martinez Peck via Glass wrote:
>
> Hi Dale,
>
> I am doing a query like this (as per your recommendation):
>
>
> nearestQueryFor: aDate on: aCollection
> | query |
> query := GsQuery fromFormula: self nearestQuery  on: aCollection.
> query bind: 'targetDate' to: aDate.
> ^ query
>
> nearestQuery
> ^ nearestQuery ifNil: [
> nearestQuery := GsQueryPredicate fromQueryStatement:  'each.date <=
> targetDate'.
> nearestQuery
> ].
>
>
> And when I use it, I do this:
>
> query := self nearestQueryFor: dateToCompare on: (self indexingDict at:
> securityUniqueId).
> stream := query reversedReadStream.
>             ^ stream atEnd
>                 ifTrue: [ nil ]
>                 ifFalse: [ stream next ]
>
> I am profiling some code that uses this a lot and I see that quite some
> time is spent in the #atEnd.
> I attach a part of the profiling output to see what I mean.
>
> Do you see something obvious I can speed up?
>
> Thanks in advance,
>
> --
> Mariano
> http://marianopeck.wordpress.com
>
>
> _______________________________________________
> Glass mailing listGlass at lists.gemtalksystems.comhttp://lists.gemtalksystems.com/mailman/listinfo/glass
>
>
>
> _______________________________________________
> Glass mailing list
> Glass at lists.gemtalksystems.com
> http://lists.gemtalksystems.com/mailman/listinfo/glass
>
>


-- 
Mariano
http://marianopeck.wordpress.com
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.gemtalksystems.com/mailman/private/glass/attachments/20171025/5066dad3/attachment.html>