On 11/29/2012 13:19, janI wrote:
Thanks I did not know that LEFT JOIN and JOIN has different speeds on inodb
tables. I made the fast fix, and split xmaint_uids into smaller tables, and
is running now.
BUT I am dead nervous of deleting wrong data !! so the review in general
would be nice.
I have also decided to post the user list here, to give people a chance to
shout and get removed from the list. There are very little margin for
errors on our database, and I would not like to cause problems (I think I
already have used this years allowance).
Thanks for your suggestions, I will implement a couple of your ideas before
I release the final script.
Jan.
Quick question: How do you expect anyone to review >30K account names? I
suggest to go ahead and delete them. --/tj/
On 29 November 2012 19:09, Andrea Pescetti <pesce...@apache.org> wrote:
On 29/11/2012 janI wrote:
ooo-wiki VM is so weak (compared to my notebook) that a lot of my
"special"
select/join statements timed out...and the just because I have a simple
where clause "where user_id in (select user_id from wiki_maint_uids)"
I only had a quick look yesterday and I cannot check now, but there were
several possible speed improvements, including using a simple JOIN instead
if a LEFT JOIN and then discarding NULL matches, introducing a primary key
or an index in the wiki_maint_uids table and using update on joins instead
of subqueries. I didn't test any of these, and I didn't see the database,
so don't trust the lines above too much! They are just semi-random thoughts
based on the code I saw yesterday, and it could turn out that these changes
slow down the queries instead of improving them.
Regards,
Andrea.
