Re: Let's drop two obsolete features which are bear-traps for novices

Josh Berkus <josh@agliodbs.com> writes:
> Of course, I'm talking about the MONEY type and hash indexes (not the
> hash ops class, which is useful, just the index type).  It's time to put
> both of these features out to pasture.  Certainly neither of theise
> features would be accepted into PostgreSQL today given the shape they're in.

I don't care one way or the other about the money type, but I will defend
hash indexes, especially seeing that we've already added a pretty
in-your-face warning as of 9.5:

regression=# create table foo(f1 int);
CREATE TABLE
regression=# create index on foo using hash (f1);
WARNING:  hash indexes are not WAL-logged and their use is discouraged
CREATE INDEX

> Now, I know the first thing someone will do is jump up and claim that
> they were just about to fix WAL-logging on hash indexes,

I don't know if/when that will happen as such, but Simon was making noises
about writing code to treat hash indexes as unlogged automatically, which
would more or less fix the worst risks.  That's not just a special case
for hash indexes, but any index AM that lacks WAL support, as third-party
AMs might well do.
        regards, tom lane