On 24/06/05, Brion Vibber <brion(a)pobox.com> wrote:
That is, instead of "copy these fields from a
million 'old' records into the 'revision' table", it chunks in say
100
records at a time.
This is probably slower 'in total' (though since we have to do UTF-8
conversion on several large wikis anyway, it's necessary to a degree),
but the main benefit is that it should allow the replication stream to
be interleaved -- a chunk of upgrade, a few edits, a chunk of upgrade, a
few edits. The slaves should stay up to date during the process, always
applying small, recent updates.
Isn't it possible that some new entries in the cur table will be left
behind? That is, once the upgrader has moved on to changing a
different part of the database, somebody makes an edit. What will
happen to their edit?