New developer TODO suggestions

Hi all

Someone recently mentioned that there's no generate_series(numeric,
numeric, numeric) .

That strikes me as a great candidate for a
new-developer-learning-PostgreSQL TODO.

A couple of other things I occasionally run into that'd fit the bill:

* A user-level elog(...) / ereport(...) function callable from SQL.
Useful in CASE statements.

* A log_ option to log whenever pg switches to a new xlog segment.

* A 'hex' option to 'decode' that decodes regular hex into bytea, or an
equivalent decode_hex / hex_decode . That's for plain undecorated hex,
not \x literals.

* A corresponding encode_hex or hex_encode to emit hex 'text' without \x
prefix (not a bytea literal)

(Yes, I know you can form bytea literals with concatenation and decode
that way, and can strip the \x prefix from a literal on output, but it's
often pretty awkward).

* A user-accessible function to decode unicode escapes like \U1011 in
strings.

* A function that converts a json array to a PostgreSQL array of a given
type if all json members are compatible with the type

* Expanding the set of json/jsonb operations to introduce features that
people are used to from jquery, mongo, etc.
Replace-key-if-exists-without-adding, add-or-replace-key, etc.

* (not really Pg proper, but enough users run into this that I think we
should encourage interested people to tackle it): In PgAdmin-III either
support \copy, \c, etc or detect their use and emit an informative error
telling the user to use 'psql'.

* When a user tries to run "psql -f some_custom_format_backup", detect
this and emit a useful error message. Ditto stdin.

* Add a built-in aggregate for array_agg(anyarray), i.e. build an array
of dims n+1 from the input arrays of dims n. For n=1 this can be done
with a simple SQL level aggregate definition, so all it really needs is
to error on dims > 1 IMO.

* Add a built-in aggregate form of array_cat

... probably other things I'm forgetting.

Worth adding some to the TODO marked beginner?

--
Craig Ringer http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services