Hi.
I've notice that there are no keys and so probably no indexes on
toolserver databases. Is this intentional?
I've used below queries - both show no keys/indexes on revision table:
SHOW COLUMNS FROMplwiki_p.revision;
SHOW INDEX FROM plwiki_p.revision;
I've also exported the whole schema and see no indexes at all... The
same for random wiki on s2 - nlwiki_p.
At first I thought this might be do to the replication, but even with
replication you need to select some stuff and only insert latest data.
And besides those are read-only databases so selecting should occur far
more frequently then inserting and so indexing is crucial for
performance. Is it not?
Why am I asking this? Well from a month or so I received a lot of query
kills which should never be killed. Why they should never be killed?
Because they are (or should be) working only on indexes:
* revision.rev_id - should be PRIMARY KEY
* revision.rev_page - should be KEY / FOREIGN KEY
My query is:
SELECT /* SLOW_OK */ MIN(rev_id) as first_rev_id
FROM revision
WHERE rev_page IN
(2,4,6,8,12,13,15,16,18,20,21,22,23,24,25,26,28,29,...)
GROUP BY rev_page
I admit the IN list is rather large, but still...
Regards,
Nux.
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