See https://quarry.wmflabs.org/query/12718 and the error message returned.
EXPLAIN only works if you have access to the underlying tables. I only have access to the VIEWs built on top of actual wiki tables (for good reason, same applies to most of us) so I get an error when I try EXPLAIN. On Fri, Sep 23, 2016 at 11:24 AM, Jaime Crespo <[email protected]> wrote: > Explain (you should be able to run SHOW EXPLAIN on your own queries: > http://s.petrunia.net/blog/?p=89): > > EXPLAIN select page_title, count(ll_lang) from page join category on > page_title = cat_title left join categorylinks on page_title = cl_to left > join templatelinks on tl_from = page_id and tl_namespace = 10 and tl_title > in ( 'رده_خالی' , 'رده_بهتر', 'رده_ابهامزدایی', 'رده_ردیابیکردن' ) left > join langlinks on page_id = ll_from where page_namespace = 14 and > page_is_redirect = 0 and cl_to is null and tl_title is null group by > page_title order by 2, 1 limit 5000\G > *************************** 1. row *************************** > id: 1 > select_type: SIMPLE > table: page > type: ref > possible_keys: name_title,page_redirect_namespace_len > key: page_redirect_namespace_len > key_len: 5 > ref: const,const > rows: 364273 > Extra: Using where; Using temporary; Using filesort > *************************** 2. row *************************** > id: 1 > select_type: SIMPLE > table: category > type: eq_ref > possible_keys: cat_title > key: cat_title > key_len: 257 > ref: fawiki.page.page_title > rows: 1 > Extra: Using index > *************************** 3. row *************************** > id: 1 > select_type: SIMPLE > table: categorylinks > type: ref > possible_keys: cl_timestamp,cl_sortkey > key: cl_timestamp > key_len: 257 > ref: fawiki.page.page_title > rows: 12 > Extra: Using where; Using index > *************************** 4. row *************************** > id: 1 > select_type: SIMPLE > table: templatelinks > type: ref > possible_keys: tl_from,tl_namespace > key: tl_namespace > key_len: 4 > ref: const > rows: 390610 > Extra: Using where; Using index > *************************** 5. row *************************** > id: 1 > select_type: SIMPLE > table: langlinks > type: ref > possible_keys: ll_from > key: ll_from > key_len: 4 > ref: fawiki.page.page_id > rows: 104910 > Extra: Using index > > On Fri, Sep 23, 2016 at 5:16 PM, Huji Lee <[email protected]> wrote: > >> Hi all, >> >> I have a query [1] which I run weekly to identify empty categories; those >> that don't have interwiki links and stay empty for a while are then deleted >> by a sysop. >> >> The query ran just fine every week until Sep 2nd. [2] Since then, the >> query times out and the page doesn't get updated. >> >> The query is no that complex (a SELECT with five JOINs) and used to >> finish in about 3-5 minutes. I don't have EXPLAIN access on Labs so I >> cannot tell what is slowing it down. Can someone kindly take a look and >> advise why this suddenly stopped working? >> >> Thanks, >> >> Huji >> >> [1] https://quarry.wmflabs.org/query/3760 >> [2] https://fa.wikipedia.org/w/index.php?title=%D9%88%DB%8C%DA% >> A9%DB%8C%E2%80%8C%D9%BE%D8%AF%DB%8C%D8%A7:%DA%AF%D8%B2%D8% >> A7%D8%B1%D8%B4_%D8%AF%DB%8C%D8%AA%D8%A7%D8%A8%DB%8C%D8%B3/ >> %D8%B1%D8%AF%D9%87%E2%80%8C%D9%87%D8%A7%DB%8C_%D8%AE%D8% >> A7%D9%84%DB%8C&action=history&uselang=en >> >> _______________________________________________ >> Labs-l mailing list >> [email protected] >> https://lists.wikimedia.org/mailman/listinfo/labs-l >> >> > > > -- > Jaime Crespo > <http://wikimedia.org> > > _______________________________________________ > Labs-l mailing list > [email protected] > https://lists.wikimedia.org/mailman/listinfo/labs-l > >
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