Do you guys welcome contribution on wikitech?
yes please! :)
On Tue, Nov 11, 2014 at 11:28 AM, Giovanni Luca Ciampaglia <
gciampag(a)indiana.edu> wrote:
> Ah, I didn't know the tables on LabsDB where actually views! That makes
> sense now. I guess the documentation should be more explicit on this. Right
> now this detail is only mentioned in passing here (emphasis added):
>
> The revision and logging tables do not have indexes on user columns. In
>> an email
>> <http://lists.wikimedia.org/pipermail/labs-l/2013-September/001607.html>,
>> one of the system administrators pointed out that this is because "those
>> values are conditionally nulled when supressed". One has to instead use the
>> correspondingrevision_userindex or logging_userindex for these types of
>> queries. *On those views*, rows where the column would have otherwise
>> been nulled are elided; this allows the indexes to be usable.
>
>
>
>
>
https://wikitech.wikimedia.org/wiki/Help:Tool_Labs/Database#Tables_for_revi…
Do you guys welcome contribution on wikitech?
>
> G
>
>
>
> Giovanni Luca Ciampaglia
>
> ✎ 919 E 10th ∙ Bloomington 47408 IN ∙ USA
> ☞
http://www.glciampaglia.com/
> ✆ +1 812 855-7261
> ✉ gciampag(a)indiana.edu
>
> 2014-11-11 8:46 GMT-05:00 Aaron Halfaker <aaron.halfaker(a)gmail.com>om>:
>
> The tables you are access on labs are actually "views". They won't
show
>> their indexes because they are the result of a query.
>>
>> Also keep in mind that some views are *not* indexed.
>>
>> For example, "revision" is not indexed, but
"revision_userindex" is.
>> Similarly, "logging" is not indexed, but "logging_userindex"
is. This is
>> confusing and cause for a lot for frustration, but there's good reason.
>> See
https://bugzilla.wikimedia.org/show_bug.cgi?id=66786
>>
>> On Tue, Nov 11, 2014 at 12:23 AM, Giovanni Luca Ciampaglia <
>> gciampag(a)indiana.edu> wrote:
>>
>>> I know the best place to ask this would be Labs-l, but I just subscribed
>>> to it and am waiting for the list admin to be added. In the meanwhile some
>>> good soul could please forward this message there?
>>>
>>> Is there a reason why the tables on the Labs replica are not indexed?
>>> Drawing a list of random titles with page_random takes more than a minute!
>>>
>>> MariaDB [enwiki_p]> select page_id, page_title, page_random from page
>>> where page_random > rand() and page_namespace = 0 order by page_random
>>> limit 10;
>>> +----------+---------------------------------------+----------------+
>>> | page_id | page_title | page_random |
>>> +----------+---------------------------------------+----------------+
>>> | 18247710 | Jack_frost_comic | 0.000597330654 |
>>> | 2102857 | Prince_Carl_Christian_of_Hohenzollern | 0.000885503126 |
>>> | 21550893 | Phoberocyon | 0.000927813129 |
>>> | 2836759 | Rinascimento | 0.000943768415 |
>>> | 20972414 | Gothic_black_metal | 0.000989090479 |
>>> | 1654899 | 1500v_DC | 0.001175443821 |
>>> | 43905082 | Juan_García_Costilla | 0.00153940668 |
>>> | 1316905 | T_subsurface_stock | 0.001564608112 |
>>> | 1447578 | RPGMaker_2000 | 0.00158874586 |
>>> | 2034084 | State_Bar_of_California | 0.001697520497 |
>>> +----------+---------------------------------------+----------------+
>>> 10 rows in set (1 min 21.14 sec)
>>>
>>> MariaDB [enwiki_p]> show index from page;
>>> Empty set (0.00 sec)
>>>
>>> MariaDB [enwiki_p]>
>>>
>>>
>>> Giovanni Luca Ciampaglia
>>>
>>> ✎ 919 E 10th ∙ Bloomington 47408 IN ∙ USA
>>> ☞
http://www.glciampaglia.com/
>>> ✆ +1 812 855-7261
>>> ✉ gciampag(a)indiana.edu
>>>
>>> _______________________________________________
>>> Wiki-research-l mailing list
>>> Wiki-research-l(a)lists.wikimedia.org
>>>
https://lists.wikimedia.org/mailman/listinfo/wiki-research-l
>>>
>>>
>>
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