(Brion Vibber brion@pobox.com):
Moving only the old data to the filesystem would also be less of a problem than moving the cur records, because we don't have the problem of losing MySQL's fulltext index, which we need to keep for the cur table to implement the search function.
Actually, that's not the case. We've always used a separate, munged text field for the searchable text (stripping HTML markup, accounting for things like changing "[[foobar]]s" to "foobar foobars", massaging Unicode chars for the non-Latin wikis to make search work right in Esperanto, Polish, Japanese, Chinese, etc).
Originally these were fields in cur, but now they're in a separate table (searchindex) since cur is InnoDB and we can only do fulltext searches on MyISAM tables.
Ah, that's right. Funny how one can forget details about one's own code (sort of; I wrote the text munging, you moved it to the new table). At any rate, yes, we could store cur text in the filesystem as well. I'll have to try that sometime.