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.