the float8 versions of the aggregates, which is all that the standard requires.
Sergey's original patch also provided versions using numeric arithmetic,
but given the size and slowness of the code, I doubt we ought to include
those in core.
the opportunity to treat COUNT(*) as a zero-argument aggregate instead
of the old hack that equated it to COUNT(1); this is materially cleaner
(no more weird ANYOID cases) and ought to be at least a tiny bit faster.
Original patch by Sergey Koposov; review, documentation, simple regression
tests, pg_dump and psql support by moi.
var_samp(), stddev_pop(), and stddev_samp(). var_samp() and stddev_samp()
are just renamings of the historical Postgres aggregates variance() and
stddev() -- the latter names have been kept for backward compatibility.
This patch includes updates for the documentation and regression tests.
The catversion has been bumped.
NB: SQL2003 requires that DISTINCT not be specified for any of these
aggregates. Per discussion on -patches, I have NOT implemented this
restriction: if the user asks for stddev(DISTINCT x), presumably they
know what they are doing.
into indexscans on matching indexes. For the moment, it only handles
int4 and text datatypes; next step is to add a column to pg_aggregate
so that all MIN/MAX aggregates can be handled. Per my recent proposal.
(1) boolean-and and boolean-or aggregates named bool_and and bool_or.
they (SHOULD;-) correspond to standard sql every and some/any aggregates.
they do not have the right name as there is a problem with
the standard and the parser for some/any. Tom also think that
the standard name is misleading because NULL are ignored.
Also add 'every' aggregate.
(2) bitwise integer aggregates named bit_and and bit_or for
int2, int4, int8 and bit types. They are not standard, but I find
them useful. I needed them once.
The patches adds:
- 2 new very short strict functions for boolean aggregates in
src/backed/utils/adt/bool.c,
src/include/utils/builtins.h and src/include/catalog/pg_proc.h
- the new aggregates declared in src/include/catalog/pg_proc.h and
src/include/catalog/pg_aggregate.h
- some documentation and validation about these new aggregates.
Fabien COELHO
extensions to support our historical behavior. An aggregate belongs
to the closest query level of any of the variables in its argument,
or the current query level if there are no variables (e.g., COUNT(*)).
The implementation involves adding an agglevelsup field to Aggref,
and treating outer aggregates like outer variables at planning time.
some of the algorithms for higher functions. I see about a factor of ten
speedup on the 'numeric' regression test, but it's unlikely that that test
is representative of real-world applications.
initdb forced due to change of on-disk representation for NUMERIC.
parameter to allow it to be forced off for comparison purposes.
Add ORDER BY clauses to a bunch of regression test queries that will
otherwise produce randomly-ordered output in the new regime.
so that precision of result is always at least as good as you'd get from
float8 arithmetic (ie, always at least 16 digits of accuracy). Per
pg_hackers discussion a few days ago.
There's now only one transition value and transition function.
NULL handling in aggregates is a lot cleaner. Also, use Numeric
accumulators instead of integer accumulators for sum/avg on integer
datatypes --- this avoids overflow at the cost of being a little slower.
Implement VARIANCE() and STDDEV() aggregates in the standard backend.
Also, enable new LIKE selectivity estimators by default. Unrelated
change, but as long as I had to force initdb anyway...
which is broken in some weird way that I don't understand. I think it
may be exposing a bug in the new psql --- for one thing, I get different
results when I run psql by hand than the regress script gets. What
the heck???
Tom Lane
Neil Conway
Bruce Momjian
Thomas G. Lockhart