On 26/09/12 03:54, Asher Feldman wrote:
<tl;dr> Where an index is desired on a mysql column of base36 encoded sha1 hashes, I recommend ADD INDEX (sha1column(10)). Shorter indexes will be sufficient in many cases, but this is still provides a >2/3 space savings while covering a huge (2^51.43) space.
We usually don't put update patches in MediaWiki for index size changes. You can change the indexes on existing Wikimedia wikis at your leisure, and we will change it in tables.sql for the benefit of new wikis.
-- Tim Starling