[dev] [commits] Horde branch master updated. c1f241be16aa88a278d0e51fc7baa78e39008cca

[Michael Rubinsky]

Quoting Chuck Hagenbuch <chuck at horde.org>:

> Any reason this isn't just an option when creating uuids?
>
> Michael M Slusarz <slusarz at horde.org> wrote:
>
>> Quoting Chuck Hagenbuch <chuck at horde.org>:
>>
>>> Quoting Michael Rubinsky <mrubinsk at horde.org>:
>>>
>>>> It seems un-friendly to require a schema simply because we've
>>>> changed our id generation for these fields. We can truncate the id
>>>> when it's generated in the affected apps, but I'm unsure how that
>>>> affects the uniqueness of the id. Or we could go back to the old
>>>> way of generating the ids in these cases. Not sure why a UUID is
>>>> needed in some of these cases - like for kronolith's event_id
>>>> field, for instance.
>>>
>>> I think we should go ahead and increase the field length, or we
>>> should go back to auto-increment ids. We don't need UUIDs here at
>>> all - I think we thought at one point that we could combine the id
>>> with the uid, but we can't, so...
>>
>> Alternatively, we could use Horde_Support_Randomid instead (which I
>> just committed) - which produces more compact IDs than the UUIDs since
>> it packs the data into base-36 instead of base-16 (and doesn't have
>> any extraneous dashes).
>>
>> michael

I've come across an issue with this implementation. I'm getting a very  
large rate of duplicates being generated when run in a loop. For  
example, when importing a large .ics file into kronolith, we are  
generating ids for the kronolith_events table fairly quickly. While  
running a test loop on my dev box, I'm getting somewhere around a 20%  
duplicate rate. I imagine it has something to do with what the  
substr() is taking off, but have to admit I'm not entirely clear how  
the base conversion affects this.

My test code is below. I realize this loop would run quicker then a  
real life scenario, but this is causing DB constraint violations for  
me when importing my calendar into kronolith. I'm seeing this in  
roughly 1 out of 3 attempts at importing it.

<code>
$values = array();
$cnt = 0;
for($i = 0; $i < 10000; $i++) {
     $id = (string)new Horde_Support_Randomid();
     if (!empty($values[$id])) {
         echo 'Duplicate: ' . $id . '<br/>';
         $cnt++;
     }
     $values[$id] = !empty($values[$id]) ? $values[$id] += 1 : 1;
}
echo 'Duplicate count: ' . $cnt;
print_r($values);

</code>

-- 
Mike

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mrubinsk at horde.org

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