Also performed an initial run through of upgrading our Copyright date to
extend to 2005 ... first run here was very simple ... change everything
where: grep 1996-2004 && the word 'Copyright' ... scanned through the
generated list with 'less' first, and after, to make sure that I only
picked up the right entries ...
In the past, we used a 'Lispy' linked list implementation: a "list" was
merely a pointer to the head node of the list. The problem with that
design is that it makes lappend() and length() linear time. This patch
fixes that problem (and others) by maintaining a count of the list
length and a pointer to the tail node along with each head node pointer.
A "list" is now a pointer to a structure containing some meta-data
about the list; the head and tail pointers in that structure refer
to ListCell structures that maintain the actual linked list of nodes.
The function names of the list API have also been changed to, I hope,
be more logically consistent. By default, the old function names are
still available; they will be disabled-by-default once the rest of
the tree has been updated to use the new API names.
unnecessary checks for complex grouping expressions: we cannot check
whether the expressions are simple Vars until after we apply
flatten_join_alias_vars, because in the case of FULL JOIN that routine
can introduce non-Var expressions. Per example from Joel Knight.
It also works to create a non-polymorphic aggregate from polymorphic
functions, should you want to do that. Regression test added, docs still
lacking. By Joe Conway, with some kibitzing from Tom Lane.
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.
that used to do it in planner. That was an ancient kluge that was
never satisfactory; errors should be detected at parse time when possible.
But at the time we didn't have the support mechanism (expression_tree_walker
et al) to make it convenient to do in the parser.
entries, per pghackers discussion. This fixes aggregates to live in
namespaces, and also simplifies/speeds up lookup in parse_func.c.
Also, add a 'proimplicit' flag to pg_proc that controls whether a type
coercion function may be invoked implicitly, or only explicitly. The
current settings of these flags are more permissive than I would like,
but we will need to debate and refine the behavior; for now, I avoided
breaking regression tests as much as I could.
the parsetree representation. As yet we don't *do* anything with schema
names, just drop 'em on the floor; but you can enter schema-compatible
command syntax, and there's even a primitive CREATE SCHEMA command.
No doc updates yet, except to note that you can now extract a field
from a function-returning-row's result with (foo(...)).fieldname.
maintained for each cache entry. A cache entry will not be freed until
the matching ReleaseSysCache call has been executed. This eliminates
worries about cache entries getting dropped while still in use. See
my posting to pg-hackers of even date for more info.
(Don't forget that an alias is required.) Views reimplemented as expanding
to subselect-in-FROM. Grouping, aggregates, DISTINCT in views actually
work now (he says optimistically). No UNION support in subselects/views
yet, but I have some ideas about that. Rule-related permissions checking
moved out of rewriter and into executor.
INITDB REQUIRED!
complaints about ungrouped variables. This is for consistency with
behavior elsewhere, notably the fact that the relname is reported as
an alias in these same complaints. Also, it'll work with subselect-
in-FROM where old code didn't.
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...
running gcc and HP's cc with warnings cranked way up. Signed vs unsigned
comparisons, routines declared static and then defined not-static,
that kind of thing. Tedious, but perhaps useful...
Implement TIME WITH TIME ZONE type (timetz internal type).
Remap length() for character strings to CHAR_LENGTH() for SQL92
and to remove the ambiguity with geometric length() functions.
Keep length() for character strings for backward compatibility.
Shrink stored views by removing internal column name list from visible rte.
Implement min(), max() for time and timetz data types.
Implement conversion of TIME to INTERVAL.
Implement abs(), mod(), fac() for the int8 data type.
Rename some math functions to generic names:
round(), sqrt(), cbrt(), pow(), etc.
Rename NUMERIC power() function to pow().
Fix int2 factorial to calculate result in int4.
Enhance the Oracle compatibility function translate() to work with string
arguments (from Edwin Ramirez).
Modify pg_proc system table to remove OID holes.
SELECT a FROM t1 tx (a);
Allow join syntax, including queries like
SELECT * FROM t1 NATURAL JOIN t2;
Update RTE structure to hold column aliases in an Attr structure.
yet, but at least we can give a better error message:
regression=> select count(distinct f1) from int4_tbl;
ERROR: aggregate(DISTINCT ...) is not implemented yet
instead of 'parser: parse error at or near distinct'.
mentioned in FROM but not elsewhere in the query: such tables should be
joined over anyway. Aside from being more standards-compliant, this allows
removal of some very ugly hacks for COUNT(*) processing. Also, allow
HAVING clause without aggregate functions, since SQL does. Clean up
CREATE RULE statement-list syntax the same way Bruce just fixed the
main stmtmulti production.
CAUTION: addition of a field to RangeTblEntry nodes breaks stored rules;
you will have to initdb if you have any rules.
sort order down into planner, instead of handling it only at the very top
level of the planner. This fixes many things. An explicit sort is now
avoided if there is a cheaper alternative (typically an indexscan) not
only for ORDER BY, but also for the internal sort of GROUP BY. It works
even when there is no other reason (such as a WHERE condition) to consider
the indexscan. It works for indexes on functions. It works for indexes
on functions, backwards. It's just so cool...
CAUTION: I have changed the representation of SortClause nodes, therefore
THIS UPDATE BREAKS STORED RULES. You will need to initdb.
is parse_aggs.c. This fixes its failure to cope with (at least) CaseExpr
and ArrayRef nodes, which is the reason why both of these fail in 6.5:
select coalesce(f1,0) from int4_tbl group by f1;
ERROR: Illegal use of aggregates or non-group column in target list
select sentence.words[0] from sentence group by sentence.words[0];
ERROR: Illegal use of aggregates or non-group column in target list
The array case still fails, but at least it's not parse_agg's fault
anymore ... considering that we now support CASE officially, I think
it's important to fix the first example ...
aggregate functions, as in
select a, b from foo group by a;
The ungrouped reference to b is not kosher, but formerly we neglected to
check this unless there was an aggregate function somewhere in the query.
PostgreSQL Daemon
Bruce Momjian
Neil Conway
Tom Lane
Peter Eisentraut
Thomas G. Lockhart
Jan Wieck