ILIKE vs indices

While tuning an application, I found the posts from 2003 recomending the
use of LOWER() and LIKE in place of ILIKE to take advantage of indices.

For this app, given the limitations of the upper-layer protocol it must
support, that change replaced about 30 minutes of repeated seq scans with
about 1 minute of repeated index scans! On a query-set often repeated
several times per day. (Probably more times per day now.)

Is there any contraindication to recasting:

foo ILIKE 'bar'

into:

LOWER(foo) LIKE LOWER('bar')

and documenting that an index has to be on LOWER(column) to benefit ILIKE?

Perhaps the parser could read the former as the latter?

-JimC
--
James Cloos <cloos(at)jhcloos(dot)com> OpenPGP: 1024D/ED7DAEA6