Thank You Like - Recount very slow

[Laird]

Solved by Laird

Thanks for indulging me in the tedious back-and-forth until I realised I could duplicate the issue on my own copy of phpMyAdmin, and debug alone.

For those who're curious, the cause seems to be that in phpMyAdmin, apparently, a bare query on the information_schema database irrevocably (for the set of simultaneously executed queries) changes the selected database to information_schema, causing subsequent ALTER TABLE queries on the intended (otherwise-selected) database to fail. That is to say that even though, say, the mybb database is selected, after running a bare query on information_schema, the value returned by SELECT database(); becomes information_schema, and use mybb; doesn't change it back to the mybb database.

The 1.1.0 version of the script I'd attached generated such a bare query:

SELECT COUNT(*)
INTO   @exist
FROM   information_schema.columns
WHERE  table_schema = database()
       AND
       column_name = 'tyl_tnumtyls'
       AND
       table_name = '{$db->table_prefix}threads';

Wrapping that bare query in a prepared statement seems to solve the problem.

I've again updated the script attached to the post selected as the solution. It is now at version 1.1.1.

... who is a proper Rock Star 

Superb being and I wish to thank him for all his time and devotion to getting thing PERFECT

Time difference is just so very massive I can't begin to say.

24 hours and wouldn't / couldn't finish!

Under a minute >>>> complete and perfect 

Thank you Laird

You're very welcome, and thank you for your generous praise.