Re: Assertion failure on UNLOGGED VIEW and SEQUENCE

Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> OK. Proposed patch attached. It looks to me like an unlogged view is
> inherently nonsensical, whereas an unlogged sequence is sensible but
> we don't implement it (and may never implement it, absent some
> evidence that the overhead of WAL logging sequence changes is worth
> getting excited about), so I wrote the error messages to reflect that
> distinction. I also added a couple of matching regression tests, and
> documented that UNLOGGED works with SELECT INTO. I put the check for
> views in DefineView adjacent to the other check that already cares
> about relpersistence, and I put the one in DefineSequence to match, at
> the top for lack of any compelling theory of where it ought to go. I
> looked at stuffing it all the way down into DefineRelation but that
> looks like it would require some other rejiggering of existing logic
> and assertions, which seems pointless and potentially prone to
> breaking things.

Regression tests for this seem pretty pointless (ie, a waste of cycles
forevermore). +1 for where you put the tests, but I don't think
ERRCODE_SYNTAX_ERROR is an appropriate errcode. I'd go with
FEATURE_NOT_SUPPORTED for both, I think. Also, it might be worth
putting some of the above justification into the comments, eg

/* Unlogged sequences are not implemented --- not clear if useful */

versus

/* Unlogged views are pretty nonsensical */

rather than duplicate comments describing non-duplicate cases.

regards, tom lane