We allow INSERT and UPDATE commands to assign to the same column more than
once, as long as the assignments are to subfields or elements rather than
the whole column. However, this failed when the target column was a domain
over array rather than plain array. Fix by teaching process_matched_tle()
to look through CoerceToDomain nodes, and add relevant test cases.
Also add a group of test cases exercising domains over array of composite.
It's doubtless accidental that CREATE DOMAIN allows this case while not
allowing straight domain over composite; but it does, so we'd better make
sure we don't break it. (I could not find any documentation mentioning
either side of that, so no doc changes.)
It's been like this for a long time, so back-patch to all supported
branches.
Discussion: https://postgr.es/m/4206.1499798337@sss.pgh.pa.us
Commit c46c0e5202 failed to pass the
TransitionCaptureState object to ExecARInsertTriggers() in the case
where it's using heap_multi_insert and there are indexes. Repair.
Thomas Munro, from a report by David Fetter
Discussion: https://postgr.es/m/20170708084213.GA14720%40fetter.org
The previous logic, whilst not actually wrong, was overly complex and
involved doing two binary searches, where only one was really
necessary. This simplifies that logic and improves the comments.
One visible change is that if the new partition overlaps multiple
existing partitions, the error message now always reports the overlap
with the first existing partition (the one with the lowest
bounds). The old code would sometimes report the clash with the first
partition and sometimes with the last one.
Original patch idea from Amit Langote, substantially rewritten by me.
Discussion: https://postgr.es/m/CAAJ_b947mowpLdxL3jo3YLKngRjrq9+Ej4ymduQTfYR+8=YAYQ@mail.gmail.com
Buildfarm members hornet and sungazer have shown multiple instances of
"Failed test 'xmin of non-cascaded slot with hs feedback has changed'".
The reason seems to be that the test is checking the current xmin of the
master server's replication slot against a past xmin of the first slave
server's replication slot. Even though the latter slot is downstream of
the former, it's possible for its reported xmin to be ahead of the former's
reported xmin, because those numbers are updated whenever the respective
downstream walreceiver feels like it (see logic in WalReceiverMain).
Instrumenting this test shows that indeed the slave slot's xmin does often
advance before the master's does, especially if an autovacuum transaction
manages to occur during the relevant window. If we happen to capture such
an advanced xmin as $xmin, then the subsequent wait_slot_xmins call can
fall through before the master's xmin has advanced at all, and then if it
advances before the get_slot_xmins call, we can get the observed failure.
Yeah, that's a bit of a long chain of deduction, but it's hard to explain
any other way how the test can get past an "xmin <> '$xmin'" check only
to have the next query find that xmin does equal $xmin.
Fix by keeping separate images of the master and slave slots' xmins
and testing their has-xmin-advanced conditions independently.
Since reducing pg_ctl's reaction time in commit c61559ec3, some
slower buildfarm members have shown erratic failures in this test.
The reason turns out to be that the test assumes synchronous
replication (because it does not provide any lag time for a commit
to replicate before shutting down the servers), but it had only
enabled sync rep in one direction. The observed symptoms correspond
to failure to replicate the last committed transaction in the other
direction, which can be expected to happen if the shutdown command
is issued soon enough and we are providing no synchronous-commit
guarantees.
Fix that, and add a bit more paranoid state checking at the bottom
of the script.
Michael Paquier and myself
Discussion: https://postgr.es/m/908.1498965681@sss.pgh.pa.us
By default, Perl's split() function drops trailing empty fields,
which is not what we want here. Oversight in commit fb093e4cb.
We'd managed to miss it thus far thanks to the very limited usage
of this function.
Discussion: https://postgr.es/m/14837.1499029831@sss.pgh.pa.us
The original coding here was very confusing, because it named the
two servers it set up "master" and "slave" even though it swapped
their replication roles multiple times. At any given point in the
script it was very unobvious whether "$node_master" actually referred
to the server named "master" or the other one. Instead, pick arbitrary
names for the two servers --- I used "london" and "paris" --- and
distinguish those permanent names from the nonce references $cur_master
and $cur_slave. Add logging to help distinguish which is which at
any given point. Also, use distinct data and transaction names to
make all the prepared transactions easily distinguishable in the
postmaster logs. (There was one place where we intentionally tested
that the server could cope with re-use of a transaction name, but
it seems like one place is sufficient for that purpose.)
Also, add checks at the end to make sure that all the transactions
that were supposed to be committed did survive.
Discussion: https://postgr.es/m/28238.1499010855@sss.pgh.pa.us
Add an optional "expected" argument to override the default assumption
that we're waiting for the query to return "t". This allows replacing
a handwritten polling loop in recovery/t/007_sync_rep.pl with use of
poll_query_until(); AFAICS that's the only remaining ad-hoc polling
loop in our TAP tests.
Change poll_query_until() to probe ten times per second not once per
second. Like some similar changes I've been making recently, the
one-second interval seems to be rooted in ancient traditions rather
than the actual likely wait duration on modern machines. I'd consider
reducing it further if there were a convenient way to spawn just one
psql for the whole loop rather than one per probe attempt.
Discussion: https://postgr.es/m/12486.1498938782@sss.pgh.pa.us
Several callers of PostgresNode::poll_query_until() neglected to check
for failure; I do not think that's optional. Also, rewrite one place
that had reinvented poll_query_until() for no very good reason.
The point of this loop is to insert 1000 rows into the test table
and consume 1000 XIDs. I can't see any good reason why it's useful
to launch 1000 psqls and 1000 backend processes to accomplish that.
Pushing the looping into a plpgsql DO block shaves about 10 seconds
off the runtime of the src/test/recovery TAP tests on my machine;
that's over 10% of the runtime of that test suite.
It is, in fact, sufficiently more efficient that we now demonstrably
need wait_slot_xmins() afterwards, or the slaves' xmins may not have
moved yet.
We now disallow having triggers with both transition tables and ON
INSERT OR UPDATE (which was a PG extension to the spec anyway),
because in this case it's not at all clear how the transition tables
should work for an INSERT ... ON CONFLICT query. Separate ON INSERT
and ON UPDATE triggers with transition tables are allowed, and the
transition tables for these reflect only the inserted and only the
updated tuples respectively.
Patch by Thomas Munro
Discussion: https://postgr.es/m/CAEepm%3D11KHQ0JmETJQihSvhZB5mUZL2xrqHeXbCeLhDiqQ39%3Dw%40mail.gmail.com
check_agg_arguments_walker threw an error upon seeing a SRF or window
function, but that is too aggressive: if the function is within a
sub-select then it's perfectly fine. I broke the SRF case in commit
0436f6bde by copying the logic for window functions ... but that was
broken too, and had been since commit eaccfded9.
Repair both cases in HEAD, and the window function case back to 9.3.
9.2 gets this right.
By default, wal_retrieve_retry_interval is five seconds, which is far
more than is needed in any of our TAP tests, leaving the test cases
just twiddling their thumbs for significant stretches. Moreover,
because it's so large, we get basically no testing of the retry-before-
master-is-ready code path. Hence, make PostgresNode::init set up
wal_retrieve_retry_interval = '500ms' as part of its customization of
test clusters' postgresql.conf. This shaves quite a few seconds off
the runtime of the recovery TAP tests.
Back-patch into 9.6. We have wal_retrieve_retry_interval in 9.5,
but the test infrastructure isn't there.
Discussion: https://postgr.es/m/31624.1498500416@sss.pgh.pa.us
Remove hard-wired sleep(2) delays in 001_stream_rep.pl in favor of using
poll_query_until to check for the desired state to appear. In addition,
add such a wait before the last test in the script, as it's possible
to demonstrate failures there after upcoming improvements in pg_ctl.
(We might end up adding polling before each of the get_slot_xmins calls in
this script, but I feel no great need to do that until shown necessary.)
In passing, clarify the description strings for some of the test cases.
Michael Paquier and Craig Ringer, pursuant to a complaint from me
Discussion: https://postgr.es/m/8962.1498425057@sss.pgh.pa.us
The comparison with the target rows on the subscriber side was done with
datumIsEqual(), which can have false negatives. For instance, it didn't
work reliably for text columns. So use the equality operator provided
by the type cache instead.
Also add more user documentation about replica identity requirements.
Reported-by: Tatsuo Ishii <ishii@sraoss.co.jp>
It's essential that initdb.c's setup_depend() scan each system catalog
that could contain objects that need to have "p" (pin) entries in pg_depend
or pg_shdepend. Forgetting to add that, either when a catalog is first
invented or when it first acquires DATA() entries, is an obvious bug
hazard. We can detect such omissions at reasonable cost by probing every
OID-containing system catalog to see whether the lowest-numbered OID in it
is pinned. If so, the catalog must have been properly accounted for in
setup_depend(). If the lowest OID is above FirstNormalObjectId then the
catalog must have been empty at the end of initdb, so it doesn't matter.
There are a small number of catalogs whose first entry is made later in
initdb than setup_depend(), resulting in nonempty expected output of the
test, but these can be manually inspected to see that they are OK. Any
future mistake of this ilk will manifest as a new entry in the test's
output.
Since pg_conversion is already in the test's output, add it to the set of
catalogs scanned by setup_depend(). That has no effect today (hence, no
catversion bump here) but it will protect us if we ever do add pin-worthy
conversions.
This test is very much like the catalog sanity checks embodied in
opr_sanity.sql and type_sanity.sql, but testing pg_depend doesn't seem to
fit naturally into either of those scripts' charters. Hence, invent a new
test script misc_sanity.sql, which can be a home for this as well as tests
on any other catalogs we might want in future.
Discussion: https://postgr.es/m/8068.1498155068@sss.pgh.pa.us
I misplaced the IF NOT EXISTS clause in commit 7b504eb282, before the
word STATISTICS. Put it where it belongs.
Patch written independently by Amit Langote and myself. I adopted his
submitted test case with a slight edit also.
Reported-by: Bruno Wolff III
Discussion: https://postgr.es/m/20170621004237.GB8337@wolff.to
Don't move parenthesized lines to the left, even if that means they
flow past the right margin.
By default, BSD indent lines up statement continuation lines that are
within parentheses so that they start just to the right of the preceding
left parenthesis. However, traditionally, if that resulted in the
continuation line extending to the right of the desired right margin,
then indent would push it left just far enough to not overrun the margin,
if it could do so without making the continuation line start to the left of
the current statement indent. That makes for a weird mix of indentations
unless one has been completely rigid about never violating the 80-column
limit.
This behavior has been pretty universally panned by Postgres developers.
Hence, disable it with indent's new -lpl switch, so that parenthesized
lines are always lined up with the preceding left paren.
This patch is much less interesting than the first round of indent
changes, but also bulkier, so I thought it best to separate the effects.
Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org
Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
Change pg_bsd_indent to follow upstream rules for placement of comments
to the right of code, and remove pgindent hack that caused comments
following #endif to not obey the general rule.
Commit e3860ffa4d wasn't actually using
the published version of pg_bsd_indent, but a hacked-up version that
tried to minimize the amount of movement of comments to the right of
code. The situation of interest is where such a comment has to be
moved to the right of its default placement at column 33 because there's
code there. BSD indent has always moved right in units of tab stops
in such cases --- but in the previous incarnation, indent was working
in 8-space tab stops, while now it knows we use 4-space tabs. So the
net result is that in about half the cases, such comments are placed
one tab stop left of before. This is better all around: it leaves
more room on the line for comment text, and it means that in such
cases the comment uniformly starts at the next 4-space tab stop after
the code, rather than sometimes one and sometimes two tabs after.
Also, ensure that comments following #endif are indented the same
as comments following other preprocessor commands such as #else.
That inconsistency turns out to have been self-inflicted damage
from a poorly-thought-through post-indent "fixup" in pgindent.
This patch is much less interesting than the first round of indent
changes, but also bulkier, so I thought it best to separate the effects.
Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org
Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
The new indent version includes numerous fixes thanks to Piotr Stefaniak.
The main changes visible in this commit are:
* Nicer formatting of function-pointer declarations.
* No longer unexpectedly removes spaces in expressions using casts,
sizeof, or offsetof.
* No longer wants to add a space in "struct structname *varname", as
well as some similar cases for const- or volatile-qualified pointers.
* Declarations using PG_USED_FOR_ASSERTS_ONLY are formatted more nicely.
* Fixes bug where comments following declarations were sometimes placed
with no space separating them from the code.
* Fixes some odd decisions for comments following case labels.
* Fixes some cases where comments following code were indented to less
than the expected column 33.
On the less good side, it now tends to put more whitespace around typedef
names that are not listed in typedefs.list. This might encourage us to
put more effort into typedef name collection; it's not really a bug in
indent itself.
There are more changes coming after this round, having to do with comment
indentation and alignment of lines appearing within parentheses. I wanted
to limit the size of the diffs to something that could be reviewed without
one's eyes completely glazing over, so it seemed better to split up the
changes as much as practical.
Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org
Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
Currently, there are no built-in functions that are SECURITY DEFINER.
But we just found an instance where one was mistakenly marked that way,
so it seems prudent to add a test about it. If we ever grow some
functions that are intentionally SECURITY DEFINER, we can alter the
expected output of this test, or adjust the query to filter out functions
for which it's okay.
Per suggestion from Robert Haas.
Discussion: https://postgr.es/m/CA+TgmoYXg7McY33+jbWmG=rS-HNUur0S6W8Q8kVNFf7epFimVA@mail.gmail.com
David Rowley found that the "use the smallest per-column selectivity"
heuristic applied in some cases by get_foreign_key_join_selectivity()
was badly off if the FK columns are independent, producing estimates
much worse than we got before that code was added in 9.6.
One case where that heuristic was used was for LEFT and FULL outer joins
with the referenced rel on the outside of the join. But we should not
really need to special-case those here. eqjoinsel() never has had such a
special case; the correction is applied by calc_joinrel_size_estimate()
instead. Let's just estimate such cases like inner joins and rely on that
later adjustment. (I think there was something of a thinko here, in that
the comments seem to be thinking about the selectivity as defined for
semi/anti joins; but that shouldn't apply to left/full joins.) Add a
regression test exercising such a case to show that this is sane in
at least some cases.
The other case where we used that heuristic was for SEMI/ANTI outer joins,
either if the referenced rel was on the outside, or if it was on the inside
but was part of a join within the RHS. In either case, the FK doesn't give
us a lot of traction towards estimating the selectivity. To ensure that
we don't have regressions from what happened before 9.6, let's punt by
ignoring the FK in such cases and applying the traditional selectivity
calculation. (We might be able to improve on that later, but for now
I just want to be sure it's not worse than 9.5.)
Report and patch by David Rowley, simplified a bit by me. Back-patch
to 9.6 where this code was added.
Discussion: https://postgr.es/m/CAKJS1f8NO8oCDcxrteohG6O72uU1saEVT9qX=R8pENr5QWerXw@mail.gmail.com
When a new base type is created using the old-style procedure of first
creating the input/output functions with "opaque" in place of the base
type, the "opaque" argument/return type is changed to the final base type,
on CREATE TYPE. However, we did not create a pg_depend record when doing
that, so the functions were left not depending on the type.
Fixes bug #14706, reported by Karen Huddleston.
Discussion: https://www.postgresql.org/message-id/20170614232259.1424.82774@wrigleys.postgresql.org
Show "All tables" property in \dRp and \dRp+. Don't list tables for
such publications in \dRp+, since it's redundant and the list could be
very long.
Author: Masahiko Sawada <sawada.mshk@gmail.com>
Author: Jeff Janes <jeff.janes@gmail.com>
In a CHECK clause, a null result means true, whereas in a WHERE clause
it means false. predtest.c provided different functions depending on
which set of semantics applied to the predicate being proved, but had
no option to control what a null meant in the clauses provided as
axioms. Add one.
Use that in the partitioning code when figuring out whether the
validation scan on a new partition can be skipped. Rip out the
old logic that attempted (not very successfully) to compensate
for the absence of the necessary support in predtest.c.
Ashutosh Bapat and Robert Haas, reviewed by Amit Langote and
incorporating feedback from Tom Lane.
Discussion: http://postgr.es/m/CAFjFpReT_kq_uwU_B8aWDxR7jNGE=P0iELycdq5oupi=xSQTOw@mail.gmail.com
expression_returns_set() used to short-circuit its recursion upon
seeing certain node types, such as DistinctExpr, that it knew the
executor did not support set-valued arguments for. That was never
inherent, though, just a reflection of laziness in execQual.c.
With the new implementation of SRFs there is no reason to think
that any scalar-valued expression node could not have a set-valued
subexpression, except for AggRefs and WindowFuncs where we know there
is a parser check rejecting it. And indeed, the shortcut causes
unexpected failures for cases such as a SRF underneath DistinctExpr,
because the planner stops looking for SRFs too soon.
Discussion: https://postgr.es/m/5259.1497044025@sss.pgh.pa.us
Table partitioning, introduced in commit f0e44751d7, added a new
relkind - RELKIND_PARTITIONED_TABLE. Update a couple of places in
PL/pgSQL to handle it. Specifically plpgsql_parse_cwordtype() and
build_row_from_class() needed updating in order to make table%ROWTYPE
and table.col%TYPE work for partitioned tables.
Dean Rasheed, reviewed by Amit Langote.
Discussion: https://postgr.es/m/CAEZATCUnNOKN8sLML9jUzxecALWpEXK3a3W7y0PgFR4%2Buhgc%3Dg%40mail.gmail.com
When we reimplemented SRFs in commit 69f4b9c85, our initial choice was
to allow the behavior to vary from historical practice in cases where a
SRF call appeared within a conditional-execution construct (currently,
only CASE or COALESCE). But that was controversial to begin with, and
subsequent discussion has resulted in a consensus that it's better to
throw an error instead of executing the query differently from before,
so long as we can provide a reasonably clear error message and a way to
rewrite the query.
Hence, add a parser mechanism to allow detection of such cases during
parse analysis. The mechanism just requires storing, in the ParseState,
a pointer to the set-returning FuncExpr or OpExpr most recently emitted
by parse analysis. Then the parsing functions for CASE and COALESCE can
detect the presence of a SRF in their arguments by noting whether this
pointer changes while analyzing their arguments. Furthermore, if it does,
it provides a suitable error cursor location for the complaint. (This
means that if there's more than one SRF in the arguments, the error will
point at the last one to be analyzed not the first. While connoisseurs of
parsing behavior might find that odd, it's unlikely the average user would
ever notice.)
While at it, we can also provide more specific error messages than before
about some pre-existing restrictions, such as no-SRFs-within-aggregates.
Also, reject at parse time cases where a NULLIF or IS DISTINCT FROM
construct would need to return a set. We've never supported that, but the
restriction is depended on in more subtle ways now, so it seems wise to
detect it at the start.
Also, provide some documentation about how to rewrite a SRF-within-CASE
query using a custom wrapper SRF.
It turns out that the information_schema.user_mapping_options view
contained an instance of exactly the behavior we're now forbidding; but
rewriting it makes it more clear and safer too.
initdb forced because of user_mapping_options change.
Patch by me, with error message suggestions from Alvaro Herrera and
Andres Freund, pursuant to a complaint from Regina Obe.
Discussion: https://postgr.es/m/000001d2d5de$d8d66170$8a832450$@pcorp.us
Table partitioning, introduced in commit f0e44751d7, added a new
relkind - RELKIND_PARTITIONED_TABLE. Update relation_is_updatable() to
handle it. Specifically, partitioned tables and simple views built on
top of them are updatable.
This affects the SQL-callable functions pg_relation_is_updatable() and
pg_column_is_updatable(), and the views information_schema.views and
information_schema.columns.
Dean Rasheed, reviewed by Ashutosh Bapat.
Discussion: https://postgr.es/m/CAEZATCXnbiFkMXgF4Ez1pmM2c-tS1z33bSq7OGbw7QQhHov%2B6Q%40mail.gmail.com
ExecInitModifyTable() thought there was a plan per partition, but no,
there's only one. The problem had escaped detection so far because there
would only be visible misbehavior if there were a SubPlan (not an InitPlan)
in the quals being duplicated for each partition. However, valgrind
detected a bogus memory access in test cases added by commit 4f7a95be2,
and investigation of that led to discovery of the bug. The additional
test case added here crashes without the patch.
Patch by Amit Langote, test case by me.
Discussion: https://postgr.es/m/10974.1497227727@sss.pgh.pa.us
The new partitioned table capability added a new relkind, namely
RELKIND_PARTITIONED_TABLE. Update fireRIRrules() to apply RLS
policies on RELKIND_PARTITIONED_TABLE as it does RELKIND_RELATION.
In addition, add RLS regression test coverage for partitioned tables.
Issue raised by Fakhroutdinov Evgenievich and patch by Mike Palmiotto.
Regression test editorializing by me.
Discussion: https://postgr.es/m/flat/20170601065959.1486.69906@wrigleys.postgresql.org
Since tuple-routing implicitly checks the partitioning constraints
at least for the levels of the partitioning hierarchy it traverses,
there's normally no need to revalidate the partitioning constraint
after performing tuple routing. However, if there's a BEFORE trigger
on the target partition, it could modify the tuple, causing the
partitioning constraint to be violated. Catch that case.
Also, instead of checking the root table's partition constraint after
tuple-routing, check it beforehand. Otherwise, the rules for when
the partitioning constraint gets checked get too complicated, because
you sometimes have to check part of the constraint but not all of it.
This effectively reverts commit 39162b2030
in favor of a different approach altogether.
Report by me. Initial debugging by Jeevan Ladhe. Patch by Amit
Langote, reviewed by me.
Discussion: http://postgr.es/m/CA+Tgmoa9DTgeVOqopieV8d1QRpddmP65aCdxyjdYDoEO5pS5KA@mail.gmail.com
The larger part of this patch replaces usages of MyProc->procLatch
with MyLatch. The latter works even early during backend startup,
where MyProc->procLatch doesn't yet. While the affected code
shouldn't run in cases where it's not initialized, it might get copied
into places where it might. Using MyLatch is simpler and a bit faster
to boot, so there's little point to stick with the previous coding.
While doing so I noticed some weaknesses around newly introduced uses
of latches that could lead to missed events, and an omitted
CHECK_FOR_INTERRUPTS() call in worker_spi.
As all the actual bugs are in v10 code, there doesn't seem to be
sufficient reason to backpatch this.
Author: Andres Freund
Discussion:
https://postgr.es/m/20170606195321.sjmenrfgl2nu6j63@alap3.anarazel.dehttps://postgr.es/m/20170606210405.sim3yl6vpudhmufo@alap3.anarazel.de
Backpatch: -
There was a grammar ambiguity between SET PUBLICATION name REFRESH and
SET PUBLICATION SKIP REFRESH, because SKIP is not a reserved word. To
resolve that, fold the refresh choice into the WITH options. Refreshing
is the default now.
Reported-by: tushar <tushar.ahuja@enterprisedb.com>
Given the possibility of race conditions and so on, it seems entirely
unsafe to just assume that shm_toc_lookup() always finds the key it's
looking for --- but that was exactly what all but one call site were
doing. To fix, add a "bool noError" argument, similarly to what we
have in many other functions, and throw an error on an unexpected
lookup failure. Remove now-redundant Asserts that a rather random
subset of call sites had.
I doubt this will throw any light on buildfarm member lorikeet's
recent failures, because if an unnoticed lookup failure were involved,
you'd kind of expect a null-pointer-dereference crash rather than the
observed symptom. But you never know ... and this is better coding
practice even if it never catches anything.
Discussion: https://postgr.es/m/9697.1496675981@sss.pgh.pa.us
If we allow this, whatever outer command has the table open will not know
about the new index and may fail to update it as needed, as shown in a
report from Laurenz Albe. We already had such a prohibition in place for
ALTER TABLE, but the CREATE INDEX syntax missed the check.
Fixing it requires an API change for DefineIndex(), which conceivably
would break third-party extensions if we were to back-patch it. Given
how long this problem has existed without being noticed, fixing it in
the back branches doesn't seem worth that risk.
Discussion: https://postgr.es/m/A737B7A37273E048B164557ADEF4A58B53A4DC9A@ntex2010i.host.magwien.gv.at
When costing a nestloop with stop-at-first-inner-match semantics, and a
non-indexscan inner path, final_cost_nestloop() wants to charge the full
scan cost of the inner rel at least once, with additional scans charged
at inner_rescan_run_cost which might be less. However the logic for
doing this effectively assumed that outer_matched_rows is at least 1.
If it's zero, which is not unlikely for a small outer rel, we ended up
charging inner_run_cost plus N times inner_rescan_run_cost, as much as
double the correct charge for an outer rel with only one row that
we're betting won't be matched. (Unless the inner rel is materialized,
in which case it has very small inner_rescan_run_cost and the cost
is not so far off what it should have been.)
The upshot of this was that the planner had a tendency to select plans
that failed to make effective use of the stop-at-first-inner-match
semantics, and that might have Materialize nodes in them even when the
predicted number of executions of the Materialize subplan was only 1.
This was not so obvious before commit 9c7f5229a, because the case only
arose in connection with semi/anti joins where there's not freedom to
reverse the join order. But with the addition of unique-inner joins,
it could result in some fairly bad planning choices, as reported by
Teodor Sigaev. Indeed, some of the test cases added by that commit
have plans that look dubious on closer inspection, and are changed
by this patch.
Fix the logic to ensure that we don't charge for too many inner scans.
I chose to adjust it so that the full-freight scan cost is associated
with an unmatched outer row if possible, not a matched one, since that
seems like a better model of what would happen at runtime.
This is a longstanding bug, but given the lesser impact in back branches,
and the lack of field complaints, I won't risk a back-patch.
Discussion: https://postgr.es/m/CAKJS1f-LzkUsFxdJ_-Luy38orQ+AdEXM5o+vANR+-pHAWPSecg@mail.gmail.com
Previously the changes to the "data" part of the sequence, i.e. the
one containing the current value, were not transactional, whereas the
definition, including minimum and maximum value were. That leads to
odd behaviour if a schema change is rolled back, with the potential
that out-of-bound sequence values can be returned.
To avoid the issue create a new relfilenode fork whenever ALTER
SEQUENCE is executed, similar to how TRUNCATE ... RESTART IDENTITY
already is already handled.
This commit also makes ALTER SEQUENCE RESTART transactional, as it
seems to be too confusing to have some forms of ALTER SEQUENCE behave
transactionally, some forms not. This way setval() and nextval() are
not transactional, but DDL is, which seems to make sense.
This commit also rolls back parts of the changes made in 3d092fe540
and f8dc1985f as they're now not needed anymore.
Author: Andres Freund
Discussion: https://postgr.es/m/20170522154227.nvafbsm62sjpbxvd@alap3.anarazel.de
Backpatch: Bug is in master/v10 only
Per our message style guidelines, error messages incorporating the
results of format_type_be() and its siblings should not add quotes
around those results, because those functions already add quotes
at need. Fix a few places that hadn't gotten that memo.
