Re: BUG #5126: convert_to preventing index scan

>>>>> "Tom" == Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> writes:

Tom> The conversion itself is dependent on changeable catalog
Tom> entries, ie, pg_conversion. So "stable" seems the appropriate
Tom> marking to me.

>> That sounds like a bit of a stretch to me... we treat lots of
>> stuff as immutable which is actually easier to change than
>> pg_conversion entries (OS locale definitions for example).

Tom> Um ... locale *is* fixed within a given database, or at least
Tom> LC_COLLATE and LC_CTYPE are. If you see cases where we have
Tom> this wrong, they may need to be revisited.

The value of LC_CTYPE etc. is fixed, but the meaning that the OS
assigns to that value can be changed (arguably more easily than
changing pg_conversion, now that we don't allow builtin conversion
funcs to be used for conversions other than the one they are coded
for).

Of course, changing the definition of a locale will break everything
until you reindex, etc., but we put up with that because the
alternatives are clearly silly.

--
Andrew.