recursion in RewriteQuery(); also, detect recursion in fireRIRrules(),
so as to catch self-referential views per example from Ryan VanderBijl.
Minor code restructuring to make it easier to catch recursive case.

the table(s) modified by the original query would get checked for the
type of write permission needed by a rule query.

Instead of Lists of integers, we now store variable-length bitmap sets.
This should be faster as well as less error-prone.

There are two implementation techniques: the executor understands a new
JOIN_IN jointype, which emits at most one matching row per left-hand row,
or the result of the IN's sub-select can be fed through a DISTINCT filter
and then joined as an ordinary relation.
Along the way, some minor code cleanup in the optimizer; notably, break
out most of the jointree-rearrangement preprocessing in planner.c and
put it in a new file prep/prepjointree.c.

simplify callers.  It turns out the common case is that the caller
does want to recurse into sub-queries, so push support for that into
these subroutines.

the cons cell it's deleting from the list.  Do this, and fix a few callers
that were bogusly assuming it wouldn't free the cons cell.

so that all executable expression nodes inherit from a common supertype
Expr.  This is somewhat of an exercise in code purity rather than any
real functional advance, but getting rid of the extra Oper or Func node
formerly used in each operator or function call should provide at least
a little space and speed improvement.
initdb forced by changes in stored-rules representation.

whose conditions might yield NULL.  The negated qual to attach to the
original query is properly 'x IS NOT TRUE', not 'NOT x'.  This fix
produces correct behavior, but we may be taking a performance hit because
the planner is much stupider about IS NOT TRUE than it is about NOT
clauses.  Future TODO: teach prepqual, other parts of planner how to
cope with BooleanTest clauses more effectively.

rather than being reordered according to INSTEAD attribute for
implementation convenience.
Also, increase compiled-in recursion depth limit from 10 to 100 rewrite
cycles.  10 seems pretty marginal for situations where multiple rules
exist for the same query.  There was a complaint about this recently,
so I'm going to bump it up.  (Perhaps we should make the limit a GUC
parameter, but that's too close to being a new feature to do in beta.)

as per recent pghackers discussions.  initdb forced due to change in
fields of stored Query nodes.

to be flexible about assignment casts without introducing ambiguity in
operator/function resolution.  Introduce a well-defined promotion hierarchy
for numeric datatypes (int2->int4->int8->numeric->float4->float8).
Change make_const to initially label numeric literals as int4, int8, or
numeric (never float8 anymore).
Explicitly mark Func and RelabelType nodes to indicate whether they came
from a function call, explicit cast, or implicit cast; use this to do
reverse-listing more accurately and without so many heuristics.
Explicit casts to char, varchar, bit, varbit will truncate or pad without
raising an error (the pre-7.2 behavior), while assigning to a column without
any explicit cast will still raise an error for wrong-length data like 7.3.
This more nearly follows the SQL spec than 7.2 behavior (we should be
reporting a 'completion condition' in the explicit-cast cases, but we have
no mechanism for that, so just do silent truncation).
Fix some problems with enforcement of typmod for array elements;
it didn't work at all in 'UPDATE ... SET array[n] = foo', for example.
Provide a generalized array_length_coerce() function to replace the
specialized per-array-type functions that used to be needed (and were
missing for NUMERIC as well as all the datetime types).
Add missing conversions int8<->float4, text<->numeric, oid<->int8.
initdb forced.

that are explicitly JOINed are not considered dependencies unless they
are actually used in the query: mere presence in the joinaliasvars
list of a JOIN RTE doesn't count as being used.  The patch touches
a number of files because I needed to generalize the API of
query_tree_walker to support an additional flag bit, but the changes
are otherwise quite small.

Gavin Sherry, Neil Conway, and Tom Lane all got their hands dirty
on this one ...

pghackers discussion around 31-Jul-02.

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.

hardwired lists of index names for each catalog, use the relcache's
mechanism for caching lists of OIDs of indexes of any table.  This
reduces the common case of updating system catalog indexes to a single
line, makes it much easier to add a new system index (in fact, you
can now do so on-the-fly if you want to), and as a nice side benefit
improves performance a little.  Per recent pghackers discussion.

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.

bitmap, if present).

Per Tom Lane's suggestion the information whether a tuple has an oid
or not is carried in the tuple descriptor.  For debugging reasons
tdhasoid is of type char, not bool.  There are predefined values for
WITHOID, WITHOUTOID and UNDEFOID.

This patch has been generated against a cvs snapshot from last week
and I don't expect it to apply cleanly to current sources.  While I
post it here for public review, I'm working on a new version against a
current snapshot.  (There's been heavy activity recently; hope to
catch up some day ...)

This is a long patch;  if it is too hard to swallow, I can provide it
in smaller pieces:

Part 1:  Accessor macros
Part 2:  tdhasoid in TupDesc
Part 3:  Regression test
Part 4:  Parameter withoid to heap_addheader
Part 5:  Eliminate t_oid from HeapTupleHeader

Part 2 is the most hairy part because of changes in the executor and
even in the parser;  the other parts are straightforward.

Up to part 4 the patched postmaster stays binary compatible to
databases created with an unpatched version.  Part 5 is small (100
lines) and finally breaks compatibility.

Manfred Koizar

  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

to build dependencies for rules, constraint expressions, and default
expressions.  Repair some problems in the original design of
recursiveDeletion() exposed by more complex dependency sets.  Fix
regression tests that were deleting things in illegal sequences.

pg_relcheck is gone; CHECK, UNIQUE, PRIMARY KEY, and FOREIGN KEY
constraints all have real live entries in pg_constraint.  pg_depend
exists, and RESTRICT/CASCADE options work on most kinds of DROP;
however, pg_depend is not yet very well populated with dependencies.
(Most of the ones that are present at this point just replace formerly
hardwired associations, such as the implicit drop of a relation's pg_type
entry when the relation is dropped.)  Need to add more logic to create
dependency entries, improve pg_dump to dump constraints in place of
indexes and triggers, and add some regression tests.

in snapshots, per my proposal of a few days ago.  Also, tweak heapam.c
routines (heap_insert, heap_update, heap_delete, heap_mark4update) to
be passed the command ID to use, instead of doing GetCurrentCommandID.
For catalog updates they'll still get passed current command ID, but
for updates generated from the main executor they'll get passed the
command ID saved in the snapshot the query is using.  This should fix
some corner cases associated with functions and triggers that advance
current command ID while an outer query is still in progress.

yesterday's proposal to pghackers.  Also remove unnecessary parameters
to heap_beginscan, heap_rescan.  I modified pg_proc.h to reflect the
new numbers of parameters for the AM interface routines, but did not
force an initdb because nothing actually looks at those fields.

some kibitzing from Tom Lane.  Not everything works yet, and there's
no documentation or regression test, but let's commit this so Joe
doesn't need to cope with tracking changes in so many files ...

messages more uniform and internationalizable: the global array
aclcheck_error_strings[] is gone in favor of a subroutine
aclcheck_error().  Partial implementation of namespace-related
permission checks --- not all done yet.

_RETURN now, since there's no need to keep 'em unique anymore.

DROP RULE and COMMENT ON RULE syntax adds an 'ON tablename' clause,
similar to TRIGGER syntaxes.  To allow loading of existing pg_dump
files containing COMMENT ON RULE, the COMMENT code will still accept
the old syntax --- but only if the target rulename is unique across
the whole database.

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.

in different namespaces.  Also, cleanup work on relation namespace
support: drop, alter, rename commands work for tables in non-default
namespaces.

in schemas other than the system namespace; however, there's no search
path yet, and not all operations work yet on tables outside the system
namespace.

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.

objects to be privilege-checked.  Some change in their APIs would be
necessary no matter what in the schema environment, and simply getting
rid of the name-based interface entirely seems like the best way.

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.

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.

initdb/regression tests pass.

spacing.  Also adds space for one-line comments.