"Guillaume Smet" <guillaume(dot)smet(at)gmail(dot)com> writes:
> The usual trick recommended in the doc is to use lower() and LIKE but
> it leads to bad row estimates (it's constant whatever the search
> pattern is)
Not if you have an index on lower(col) which one supposes you'd have
anyway for such an application. Or are you running an ancient PG
release?
regards, tom lane