Tom Lane [Mon, 27 Jan 2003 20:51:54 +0000 (20:51 +0000)]
Upgrade cost estimation for joins, per discussion with Bradley Baetz.
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.
Tom Lane [Sat, 25 Jan 2003 23:10:30 +0000 (23:10 +0000)]
Allow the planner to collapse explicit inner JOINs together, rather than
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.)
Tom Lane [Sat, 25 Jan 2003 05:19:47 +0000 (05:19 +0000)]
Where available, use utime() or utimes() to update the file mod time
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.
Tom Lane [Sat, 25 Jan 2003 03:06:04 +0000 (03:06 +0000)]
Use stat(2) to probe for existing xlog segments in InstallXLogFileSegment,
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.
Tom Lane [Fri, 24 Jan 2003 03:58:44 +0000 (03:58 +0000)]
Modify planner's implied-equality-deduction code so that when a set
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.
Peter Eisentraut [Thu, 23 Jan 2003 23:39:07 +0000 (23:39 +0000)]
Grant options, and cascading revoke. Grant options are allowed only for
users right now, not groups. Extension of has_foo_privileges functions to
query the grant options. Extension of aclitem type to store grantor.
Tom Lane [Thu, 23 Jan 2003 05:10:41 +0000 (05:10 +0000)]
Change CREATE TABLE AS / SELECT INTO to create the new table with OIDs,
for backwards compatibility with pre-7.3 behavior. Per discussion on
pgsql-general and pgsql-hackers.
Tom Lane [Thu, 23 Jan 2003 01:22:59 +0000 (01:22 +0000)]
Update 'Mathematical Functions' table to reflect 7.3 addition of float8
forms of ceil(), floor(), sign(). Back-patch this and other recent
doc fixes in this file to the 7.3 branch.
Tom Lane [Tue, 21 Jan 2003 22:06:12 +0000 (22:06 +0000)]
Fix coredump problem in plpgsql's RETURN NEXT. When a SELECT INTO
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.
Tom Lane [Mon, 20 Jan 2003 18:55:07 +0000 (18:55 +0000)]
IN clauses appearing at top level of WHERE can now be handled as joins.
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.
Tom Lane [Fri, 17 Jan 2003 03:25:04 +0000 (03:25 +0000)]
Fix parse_agg.c to detect ungrouped Vars in sub-SELECTs; remove code
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.
Tom Lane [Fri, 17 Jan 2003 02:01:21 +0000 (02:01 +0000)]
Adjust API of expression_tree_mutator and query_tree_mutator to
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.
Tom Lane [Thu, 16 Jan 2003 21:01:45 +0000 (21:01 +0000)]
Add code to print information about a detected deadlock cycle. The
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.
Tom Lane [Thu, 16 Jan 2003 00:26:49 +0000 (00:26 +0000)]
Repair an embarrassingly large number of alphabetization mistakes in the
datetime token tables. Even more embarrassing, the regression tests
revealed some of the problems --- but evidently the bogus output wasn't
questioned. Add code to postmaster startup to directly check the tables
for correct ordering, in hopes of not being embarrassed like this again.
Tom Lane [Wed, 15 Jan 2003 23:10:32 +0000 (23:10 +0000)]
Now that switch_outer processing no longer relies on being run after
join_references(), it's practical to consolidate all join_references()
processing into the set_plan_references traversal in setrefs.c. This
seems considerably cleaner than the old way where we did it for join
quals in createplan.c and for targetlists in setrefs.c.
Tom Lane [Wed, 15 Jan 2003 19:35:48 +0000 (19:35 +0000)]
Allow merge and hash joins to occur on arbitrary expressions (anything not
containing a volatile function), rather than only on 'Var = Var' clauses
as before. This makes it practical to do flatten_join_alias_vars at the
start of planning, which in turn eliminates a bunch of klugery inside the
planner to deal with alias vars. As a free side effect, we now detect
implied equality of non-Var expressions; for example in
SELECT ... WHERE a.x = b.y and b.y = 42
we will deduce a.x = 42 and use that as a restriction qual on a. Also,
we can remove the restriction introduced 12/5/02 to prevent pullup of
subqueries whose targetlists contain sublinks.
Still TODO: make statistical estimation routines in selfuncs.c and costsize.c
smarter about expressions that are more complex than plain Vars. The need
for this is considerably greater now that we have to be able to estimate
the suitability of merge and hash join techniques on such expressions.
Barry Lind [Tue, 14 Jan 2003 09:13:51 +0000 (09:13 +0000)]
Patch from Florian Wunderlich to correctly support java Timestamps. Previously
the code would only capture milliseconds where as both postgres and the java
Timestamp object support greater resolution.
Also fixed a bug reported by Rhett Sutphin where the last digit of the
fractional seconds was lost when using timestamp without time zone
Barry Lind [Tue, 14 Jan 2003 05:05:26 +0000 (05:05 +0000)]
Patch from Kris Jurka to improve the performance of getImportedKeys().
Use explicit joins to avoid using the genetic query optimizer. Also fixed
a regression test that was failing to compile. This change also cleans up
how key names are reported as per:
A change to the value of the FK_NAME column. Currently the returned value
is the triggers arguments which look like
This was required for server versions < 7.3 when a user did not supply
constraint names. Every constraint was named "<unnamed>"
. 7.3 has enforced unique constraint names per table so unnamed foreign
keys will have different names "$1", "$2" and so on. I've used logic
along the lines of the following to preserve the unique names in the
original scheme, but allow people who go to the trouble of naming their
constraints to see them:
if (triggerargs.startsWith("<unnamed>")) {
fkname = [the whole ugly trigger args name originally used];
} else {
fkname = [the actual fk name];
}
Tom Lane [Mon, 13 Jan 2003 18:10:53 +0000 (18:10 +0000)]
Reconsider mechanism for marking sub-selects that are at top level of
a qualification clause (and hence can get away with being sloppy about
distinguishing FALSE from UNKNOWN). We need to know this in subselect.c;
marking the subplans in setrefs.c is too late.
Tom Lane [Mon, 13 Jan 2003 00:29:26 +0000 (00:29 +0000)]
Cause planner to account for evaluation costs in targetlists and
HAVING quals. Normally this is an insignificant effect --- but it
will not be insignificant when these clauses contain sub-selects.
The added costs cannot affect the planning of the query containing
them, but they might have an impact when the query is a sub-query
of a larger one.
Tom Lane [Sun, 12 Jan 2003 22:35:29 +0000 (22:35 +0000)]
Revise cost_qual_eval() to compute both startup (one-time) and per-tuple
costs for expression evaluation, not only per-tuple cost as before.
This extension is needed in order to deal realistically with hashed or
materialized sub-selects.
Bruce Momjian [Sat, 11 Jan 2003 05:04:14 +0000 (05:04 +0000)]
> > This patch improves the documentation for the shared_buffers GUC param.
>
> I'd suggest that the runtime.sgml description explicitly say "values of
> at least a few thousand are recommended for production installations".
Tom Lane [Fri, 10 Jan 2003 21:08:15 +0000 (21:08 +0000)]
Further tweaking of parsetree & plantree representation of SubLinks.
Simplify SubLink by storing just a List of operator OIDs, instead of
a list of incomplete OpExprs --- that was a bizarre and bulky choice,
with no redeeming social value since we have to build new OpExprs
anyway when forming the plan tree.
Tom Lane [Thu, 9 Jan 2003 20:50:53 +0000 (20:50 +0000)]
Adjust parser so that 'x NOT IN (subselect)' is converted to
'NOT (x IN (subselect))', that is 'NOT (x = ANY (subselect))',
rather than 'x <> ALL (subselect)' as we formerly did. This
opens the door to optimizing NOT IN the same way as IN, whereas
there's no hope of optimizing the expression using <>. Also,
convert 'x <> ALL (subselect)' to the NOT(IN) style, so that
the optimization will be available when processing rules dumped
by older Postgres versions.
initdb forced due to small change in SubLink node representation.
Tom Lane [Thu, 9 Jan 2003 01:06:57 +0000 (01:06 +0000)]
Repair inconsistent rounding behavior for timestamp, time, interval,
per gripe from Csaba Nagy. There is still potential for platform-specific
behavior for values that are exactly halfway between integers, but at
least we now get the expected answer for all other cases.
Tom Lane [Thu, 9 Jan 2003 00:58:41 +0000 (00:58 +0000)]
Add missing pg_proc entry for interval_scale(). The lack of this entry
causes interval rounding not to work as expected in 7.3, for example
SELECT '18:17:15.6'::interval(0) does not round the value.
I did not force initdb, but one is needed to install the added row.