Backpatch to 7.3.X.

> * Add the concept of dataspaces/tablespaces [tablespaces]
307d307
< * Add the concept of dataspaces/tablespaces [tablespaces]

Try to model the effect of rescanning input tuples in mergejoins;
account for JOIN_IN short-circuiting where appropriate.  Also, recognize
that mergejoin and hashjoin clauses may now be more than single operator
calls, so we have to charge appropriate execution costs.

Problem reported and fixed by Oliver Elphick.

suggestion of Peter.

> * Add group object ownership, so groups can rename/drop/grant on objects,
>   so we can implement roles

necessarily following the JOIN syntax to develop the query plan.  The old
behavior is still available by setting GUC variable JOIN_COLLAPSE_LIMIT
to 1.  Also create a GUC variable FROM_COLLAPSE_LIMIT to control the
similar decision about when to collapse sub-SELECT lists into their parent
lists.  (This behavior existed already, but the limit was always
GEQO_THRESHOLD/2; now it's separately adjustable.)

of the socket file and socket lock file; this should prevent both of them
from being removed by even the stupidest varieties of /tmp-cleaning
script.  Per suggestion from Giles Lean.

rather than actually opening the files.  This eliminates some corner cases
where the file indeed exists but open() fails for another reason, such
as being out of file descriptors.  The net reliability gain is probably
tiny, since xlog.c is full of other file open calls that will elog(PANIC)
if they fail for any reason; but this specific failure mode has been
observed in the field, so we may as well fix it.

of known-equal expressions includes any constant expressions (including
Params from outer queries), we actively suppress any 'var = var'
clauses that are or could be deduced from the set, generating only the
deducible 'var = const' clauses instead.  The idea here is to push down
the restrictions implied by the equality set to base relations whenever
possible.  Once we have applied the 'var = const' clauses, the 'var = var'
clauses are redundant, and should be suppressed both to save work at
execution and to avoid double-counting restrictivity.

users right now, not groups.  Extension of has_foo_privileges functions to
query the grant options.  Extension of aclitem type to store grantor.

for backwards compatibility with pre-7.3 behavior.  Per discussion on
pgsql-general and pgsql-hackers.

forms of ceil(), floor(), sign().  Back-patch this and other recent
doc fixes in this file to the 7.3 branch.

example from RaÇl GutiÅrrez.

DISTINCT processing on the output of an IN sub-select.

that's selecting into a RECORD variable returns zero rows, make it
assign an all-nulls row to the RECORD; this is consistent with what
happens when the SELECT INTO target is not a RECORD.  In support of
this, tweak the SPI code so that a valid tuple descriptor is returned
even when a SPI select returns no rows.

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.

including:

- replacing all the appropriate usages of <citetitle>PostgreSQL
...</citetitle> with &cite-user;, &cite-admin;, and so on

- fix an omission in the EXECUTE documentation

- add some more text to the EXPLAIN documentation

- improve the PL/PgSQL RETURN NEXT documentation (more work to do here)

- minor markup fixes


Neil Conway

     set-returning functions or SRF's.

for clarity.

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.

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.

printed data is comparable to what you could read in the pg_locks view,
were you fortunate enough to have been looking at it at the right time.

with result that flatten_join_alias_vars failed to descend into subselects.