array header, and to compute sizing and alignment of array elements
the same way normal tuple access operations do --- viz, using the
tupmacs.h macros att_addlength and att_align. This makes the world
safe for arrays of cstrings or intervals, and should make it much
easier to write array-type-polymorphic functions; as examples see
the cleanups of array_out and contrib/array_iterator. By Joe Conway
and Tom Lane.
code review by Tom Lane. Remaining issues: functions that take or
return tuple types are likely to break if one drops (or adds!)
a column in the table defining the type. Need to think about what
to do here.
Along the way: some code review for recent COPY changes; mark system
columns attnotnull = true where appropriate, per discussion a month ago.
COPY x (a,d,c,b) from stdin;
COPY x (a,c) to stdout;
as well as the corresponding changes to pg_dump to use the new
functionality. This functionality is not available when using
the BINARY option. If a column is not specified in the COPY FROM
statement, its default values will be used.
In addition to this functionality, I tweaked a couple of the
error messages emitted by the new COPY <options> checks.
Brent Verner
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.
INSERT statements to the planner. Taking it out of the parser was right
(so that defaults don't get into stored rules), but it has to happen
before rewrite rule expansion, else references to NEW.field behave
incorrectly. Accordingly, add a step to the rewriter to insert defaults
just before rewrite-rule expansion.
addRangeTableEntry calls. Remove relname field from RTEs, since
it will no longer be a useful unique identifier of relations;
we want to encourage people to rely on the relation OID instead.
Further work on dumping qual expressions in EXPLAIN, too.
now has an RTE of its own, and references to its outputs now are Vars
referencing the JOIN RTE, rather than CASE-expressions. This allows
reverse-listing in ruleutils.c to use the correct alias easily, rather
than painfully reverse-engineering the alias namespace as it used to do.
Also, nested FULL JOINs work correctly, because the result of the inner
joins are simple Vars that the planner can cope with. This fixes a bug
reported a couple times now, notably by Tatsuo on 18-Nov-01. The alias
Vars are expanded into COALESCE expressions where needed at the very end
of planning, rather than during parsing.
Also, beginnings of support for showing plan qualifier expressions in
EXPLAIN. There are probably still cases that need work.
initdb forced due to change of stored-rule representation.
in cases of qualified rules as well as unqualified ones. Tweak rules
test to avoid cluttering output with dummy SELECT results. Update
documentation to match code.
manipulation of rtable/jointree by planner. Rewriter was generating
actions that shared rtable/jointree substructure, which caused havoc
when planner got to the later actions that it'd already mucked up.
or view that's been dropped and then recreated with the same name (but,
perhaps, different columns). Eventually we'd like to support this but
for now all we can do is fail cleanly, rather than possibly coredumping
if we proceed using the obsolete rule.
original table ('OLD' table) in its join tree if OLD is referenced by
either the rule action, the rule qual, or the original query qual that
will be added to the rule action. However, we only want one instance
of the original table to be included; so beware of the possibility that
the rule action already has a jointree entry for OLD.
work where we can (given that the executor only handles it at top level)
and generate an error where we can't. Note that while the parser has
been allowing views to say SELECT FOR UPDATE for a few weeks now, that
hasn't actually worked until just now.
report from Joel Burton. Turns out that my simple idea of turning the
SELECT into a subquery does not interact well *at all* with the way the
rule rewriter works. Really what we need to make INSERT ... SELECT work
cleanly is to decouple targetlists from rangetables: an INSERT ... SELECT
wants to have two levels of targetlist but only one rangetable. No time
for that for 7.1, however, so I've inserted some ugly hacks to make the
rewriter know explicitly about the structure of INSERT ... SELECT queries.
Ugh :-(
(WAL logging for this is not done yet, however.) Clean up a number of really
crufty things that are no longer needed now that DROP behaves nicely. Make
temp table mapper do the right things when drop or rename affecting a temp
table is rolled back. Also, remove "relation modified while in use" error
check, in favor of locking tables at first reference and holding that lock
throughout the statement.
SQL92 semantics, including support for ALL option. All three can be used
in subqueries and views. DISTINCT and ORDER BY work now in views, too.
This rewrite fixes many problems with cross-datatype UNIONs and INSERT/SELECT
where the SELECT yields different datatypes than the INSERT needs. I did
that by making UNION subqueries and SELECT in INSERT be treated like
subselects-in-FROM, thereby allowing an extra level of targetlist where the
datatype conversions can be inserted safely.
INITDB NEEDED!
(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!
user is now defined in terms of the user id, the user name is only computed
upon request (for display purposes). This is kind of the opposite of the
previous state, which would maintain the user name and compute the user id
for permission checks.
Besides perhaps saving a few cycles (integer vs string), this now creates a
single point of attack for changing the user id during a connection, for
purposes of "setuid" functions, etc.
from Param nodes, per discussion a few days ago on pghackers. Add new
expression node type FieldSelect that implements the functionality where
it's actually needed. Clean up some other unused fields in Func nodes
as well.
NOTE: initdb forced due to change in stored expression trees for rules.
entry that has rules. This allows us to release the rule parsetrees
on relcache flush without needing a working freeObject() routine.
Formerly, the rule trees were leaked permanently at relcache flush.
Also, clean up handling of rule creation and deletion --- there was
not sufficient locking of the relation being modified, and there was
no reliable notification of other backends that a relcache reload
was needed. Also, clean up relcache.c code so that scans of system
tables needed to load a relcache entry are done in the caller's
memory context, not in CacheMemoryContext. This prevents any
un-pfreed memory from those scans from becoming a permanent memory
leak.
to give wrong results: it should be looking at inJoinSet not inFromCl.
Also, make 'modified' flag be local to ApplyRetrieveRule: we should
append a rule's quals to the query iff that particular rule applies,
not if we have fired any previously-considered rule for the query!
be an expression not just a simple Var, so long as only one table is
referenced (so that code isn't really any more difficult than before).
This whole thing is still fundamentally bogus, but at least we can accept
a few more cases than before.
mark query as having subselects if a subselect was added from a rule
WHERE condition (as opposed to a rule action). Also, fix adjustment
of varlevelsup so that it actually has some prospect of working when
inserting an expression containing a subselect into a subquery.
SELECT DISTINCT ON (expr [, expr ...]) targetlist ...
and there is a check to make sure that the user didn't specify an ORDER BY
that's incompatible with the DISTINCT operation.
Reimplement nodeUnique and nodeGroup to use the proper datatype-specific
equality function for each column being compared --- they used to do
bitwise comparisons or convert the data to text strings and strcmp().
(To add insult to injury, they'd look up the conversion functions once
for each tuple...) Parse/plan representation of DISTINCT is now a list
of SortClause nodes.
initdb forced by querytree change...
subselects can only appear on the righthand side of a binary operator.
That's still true for quantified predicates like x = ANY (SELECT ...),
but a subselect that delivers a single result can now appear anywhere
in an expression. This is implemented by changing EXPR_SUBLINK sublinks
to represent just the (SELECT ...) expression, without any 'left hand
side' or combining operator --- so they're now more like EXISTS_SUBLINK.
To handle the case of '(x, y, z) = (SELECT ...)', I added a new sublink
type MULTIEXPR_SUBLINK, which acts just like EXPR_SUBLINK used to.
But the grammar will only generate one for a multiple-left-hand-side
row expression.
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.
modifyAggrefQual. This routine really, really needs to be retired, but
until we have subselects in FROM there's no chance of doing the job right.
In the meantime try to respond to unhandlable cases with elog rather than
coredump.
expression_tree_mutator rather than ad-hoc tree walking code. This shortens
the code materially and fixes a fair number of sins of omission. Also,
change modifyAggrefQual to *not* recurse into subselects, since its mission
is satisfied if it removes aggregate functions from the top level of a
WHERE clause. This cures problems with queries of the form SELECT ...
WHERE x IN (SELECT ... HAVING something-using-an-aggregate), which would
formerly get mucked up by modifyAggrefQual. The routine is still
fundamentally broken, of course, but I don't think there's any way to get
rid of it before we implement subselects in FROM ...
