The parser code that transformed VALUES from row-oriented to
column-oriented lists failed if there were zero columns.
You can't write that straightforwardly (though probably you
should be able to), but the case can be reached by expanding
a "tab.*" reference to a zero-column table.
Per bug #17477 from Wang Ke. Back-patch to all supported branches.
Discussion: https://postgr.es/m/17477-0af3c6ac6b0a6ae0@postgresql.org
The idea behind this patch is to make it possible to run individual
test scripts without running the entire core test suite. Making all
the scripts completely independent would involve a massive rewrite,
and would probably be worse for coverage of things like concurrent DDL.
So this patch just does what seems practical with limited changes.
The net effect is that any test script can be run after running
limited earlier dependencies:
* all scripts depend on test_setup
* many scripts depend on create_index
* other dependencies are few in number, and are documented in
the parallel_schedule file.
To accomplish this, I chose a small number of commonly-used tables
and moved their creation and filling into test_setup. Later scripts
are expected not to modify these tables' data contents, for fear of
affecting other scripts' results. Also, our former habit of declaring
all C functions in one place is now gone in favor of declaring them
where they're used, if that's just one script, or in test_setup if
necessary.
There's more that could be done to remove some of the remaining
inter-script dependencies, but significantly more-invasive changes
would be needed, and at least for now it doesn't seem worth it.
Discussion: https://postgr.es/m/1114748.1640383217@sss.pgh.pa.us
These test cases could be adversely affected by an upcoming change
to allow pullup of FROM-less subqueries. Tweak them to ensure that
they'll continue to test what they did before.
Discussion: https://postgr.es/m/5395.1539275668@sss.pgh.pa.us
Since recent commit 1c7c317c, temporary relations cannot be mixed with
permanent relations within the same partition tree, and the same counts
for temporary relations created by other sessions, which the planner
simply discarded. Instead be paranoid and issue an error, as those
should be blocked at definition time, at least for now.
At the same time, a test case is added to stress what has been moved
when expand_partitioned_rtentry gets called recursively but bumps on a
partitioned relation with no partitions which should be handled the same
way as the non-inheritance case. This code may be reworked in a close
future, and covering this code path will limit surprises.
Reported-by: David Rowley
Author: David Rowley
Reviewed-by: Amit Langote, Robert Haas, Michael Paquier
Discussion: https://postgr.es/m/CAKJS1f_HyV1txn_4XSdH5EOhBMYaCwsXyAj6bHXk9gOu4JKsbw@mail.gmail.com
This exposes the existing explain summary option to users to allow them
to choose if they wish to have the planning time and totalled run time
included in the EXPLAIN result. The existing default behavior is
retained if SUMMARY is not specified- running explain without analyze
will not print the summary lines (just the planning time, currently)
while running explain with analyze will include the summary lines (both
the planning time and the totalled execution time).
Users who wish to see the summary information for plain explain can now
use: EXPLAIN (SUMMARY ON) query; Users who do not want to have the
summary printed for an analyze run can use:
EXPLAIN (ANALYZE ON, SUMMARY OFF) query;
With this, we can now also have EXPLAIN ANALYZE queries included in our
regression tests by using:
EXPLAIN (ANALYZE ON, TIMING OFF, SUMMARY off) query;
I went ahead and added an example of this, which will hopefully not make
the buildfarm complain.
Author: Ashutosh Bapat
Discussion: https://postgr.es/m/CAFjFpReE5z2h98U2Vuia8hcEkpRRwrauRjHmyE44hNv8-xk+XA@mail.gmail.com
Previously, the planner would reject an index-only scan if any restriction
clause for its table used a column not available from the index, even
if that restriction clause would later be dropped from the plan entirely
because it's implied by the index's predicate. This is a fairly common
situation for partial indexes because predicates using columns not included
in the index are often the most useful kind of predicate, and we have to
duplicate (or at least imply) the predicate in the WHERE clause in order
to get the index to be considered at all. So index-only scans were
essentially unavailable with such partial indexes.
To fix, we have to do detection of implied-by-predicate clauses much
earlier in the planner. This patch puts it in check_index_predicates
(nee check_partial_indexes), meaning it gets done for every partial index,
whereas we previously only considered this issue at createplan time,
so that the work was only done for an index actually selected for use.
That could result in a noticeable planning slowdown for queries against
tables with many partial indexes. However, testing suggested that there
isn't really a significant cost, especially not with reasonable numbers
of partial indexes. We do get a small additional benefit, which is that
cost_index is more accurate since it correctly discounts the evaluation
cost of clauses that will be removed. We can also avoid considering such
clauses as potential indexquals, which saves useless matching cycles in
the case where the predicate columns aren't in the index, and prevents
generating bogus plans that double-count the clause's selectivity when
the columns are in the index.
Tomas Vondra and Kyotaro Horiguchi, reviewed by Kevin Grittner and
Konstantin Knizhnik, and whacked around a little by me
The original coding correctly noted that these aren't just redundancies
(they're effectively X IS NOT NULL, assuming = is strict). However, they
got treated that way if X happened to be in a single-member EquivalenceClass
already, which could happen if there was an ORDER BY X clause, for instance.
The simplest and most reliable solution seems to be to not try to process
such clauses through the EquivalenceClass machinery; just throw them back
for traditional processing. The amount of work that'd be needed to be
smarter than that seems out of proportion to the benefit.
Per bug #5084 from Bernt Marius Johnsen, and analysis by Andrew Gierth.
equally (in glibc: et_EE, sv_SE, tk_TM). It turns out that this was
already taken care of previously by select_1.out, which I had forgotten to
update for an unrelated change. But might as well avoid the issue
altogether.
ORDER BY <constant> as redundant. One is that this means query_planner()
has to canonicalize pathkeys even when the query jointree is empty;
the canonicalization was always a no-op in such cases before, but no more.
Also, we have to guard against thinking that a set-returning function is
"constant" for this purpose. Add a couple of regression tests for these
evidently under-tested cases. Per report from Greg Stark and subsequent
experimentation.
First, genericcostestimate() was being way too liberal about including
partial-index conditions in its selectivity estimate, resulting in
substantial underestimates for situations such as an indexqual "x = 42"
used with an index on x "WHERE x >= 40 AND x < 50". While the code is
intentionally set up to favor selecting partial indexes when available,
this was too much...
Second, choose_bitmap_and() was likewise easily fooled by cases of this
type, since it would similarly think that the partial index had selectivity
independent of the indexqual.
Fixed by using predicate_implied_by() rather than simple equality checks
to determine redundancy. This is a good deal more expensive but I don't
see much alternative. At least the extra cost is only paid when there's
actually a partial index under consideration.
Per report from Jeff Davis. I'm not going to risk back-patching this,
though.
per-column options for btree indexes. The planner's support for this is still
pretty rudimentary; it does not yet know how to plan mergejoins with
nondefault ordering options. The documentation is pretty rudimentary, too.
I'll work on improving that stuff later.
Note incompatible change from prior behavior: ORDER BY ... USING will now be
rejected if the operator is not a less-than or greater-than member of some
btree opclass. This prevents less-than-sane behavior if an operator that
doesn't actually define a proper sort ordering is selected.
in UPDATE. We also now issue a NOTICE if a query has _any_ implicit
range table entries -- in the past, we would only warn about implicit
RTEs in SELECTs with at least one explicit RTE.
As a result of the warning change, 25 of the regression tests had to
be updated. I also took the opportunity to remove some bogus whitespace
differences between some of the float4 and float8 variants. I believe
I have correctly updated all the platform-specific variants, but let
me know if that's not the case.
Original patch for DELETE ... USING from Euler Taveira de Oliveira,
reworked by Neil Conway.
Implements between (symmetric / asymmetric) as a node.
Executes the left or right expression once, makes a Const out of the
resulting Datum and executes the >=, <= portions out of the Const sets.
Of course, the parser does a fair amount of preparatory work for this to
happen.
Rod Taylor
Note: I didn't force an initdb, figuring that one today was enough.
However, there is a new function in pg_proc.h, and pg_dump won't be
able to dump partial indexes until you add that function.
accesses versus sequential accesses, a (very crude) estimate of the
effects of caching on random page accesses, and cost to evaluate WHERE-
clause expressions. Export critical parameters for this model as SET
variables. Also, create SET variables for the planner's enable flags
(enable_seqscan, enable_indexscan, etc) so that these can be controlled
more conveniently than via PGOPTIONS.
Planner now estimates both startup cost (cost before retrieving
first tuple) and total cost of each path, so it can optimize queries
with LIMIT on a reasonable basis by interpolating between these costs.
Same facility is a win for EXISTS(...) subqueries and some other cases.
Redesign pathkey representation to achieve a major speedup in planning
(I saw as much as 5X on a 10-way join); also minor changes in planner
to reduce memory consumption by recycling discarded Path nodes and
not constructing unnecessary lists.
Minor cleanups to display more-plausible costs in some cases in
EXPLAIN output.
Initdb forced by change in interface to index cost estimation
functions.
Tom Lane
Michael Paquier
Stephen Frost
Peter Eisentraut
Neil Conway
Bruce Momjian
Thomas G. Lockhart
Vadim B. Mikheev
Marc G. Fournier