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
Table partitioning, introduced in commit f0e44751d7, added a new
relkind - RELKIND_PARTITIONED_TABLE. Update
RemoveRoleFromObjectPolicy() to handle it, otherwise DROP OWNED BY
will fail if the role has any RLS policies referring to 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 39162b2030fb0a35a6bb28dc636b5a71b8df8d1c
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.
json_populate_record throws an error if asked to convert a JSON scalar
or array into a composite type. jsonb_populate_record was returning
a record full of NULL fields instead. It seems better to make it
throw an error for this case as well.
Nikita Glukhov
Discussion: https://postgr.es/m/fbd1d566-bba0-a3de-d6d0-d3b1d7c24ff2@postgrespro.ru
Fix failure to check that we got a plain Const from const-simplification of
a coercion request. This is the cause of bug #14666 from Tian Bing: there
is an int4 to money cast, but it's only stable not immutable (because of
dependence on lc_monetary), resulting in a FuncExpr that the code was
miserably unequipped to deal with, or indeed even to notice that it was
failing to deal with. Add test cases around this coercion behavior.
In view of the above, sprinkle the code liberally with castNode() macros,
in hope of catching the next such bug a bit sooner. Also, change some
functions that were randomly declared to take Node* to take more specific
pointer types. And change some struct fields that were declared Node*
but could be given more specific types, allowing removal of assorted
explicit casts.
Place PARTITION_MAX_KEYS check a bit closer to the code it's protecting.
Likewise check only-one-key-for-list-partitioning restriction in a less
random place.
Avoid not-per-project-style usages like !strcmp(...).
Fix assorted failures to avoid scribbling on the input of parse
transformation. I'm not sure how necessary this is, but it's entirely
silly for these functions to be expending cycles to avoid that and not
getting it right.
Add guards against partitioning on system columns.
Put backend/nodes/ support code into an order that matches handling
of these node types elsewhere.
Annotate the fact that somebody added location fields to PartitionBoundSpec
and PartitionRangeDatum but forgot to handle them in
outfuncs.c/readfuncs.c. This is fairly harmless for production purposes
(since readfuncs.c would just substitute -1 anyway) but it's still bogus.
It's not worth forcing a post-beta1 initdb just to fix this, but if we
have another reason to force initdb before 10.0, we should go back and
clean this up.
Contrariwise, somebody added location fields to PartitionElem and
PartitionSpec but forgot to teach exprLocation() about them.
Consolidate duplicative code in transformPartitionBound().
Improve a couple of error messages.
Improve assorted commentary.
Re-pgindent the files touched by this patch; this affects a few comment
blocks that must have been added quite recently.
Report: https://postgr.es/m/20170524024550.29935.14396@wrigleys.postgresql.org
Use 'COLLATE "C"' to force locale-independent sorting of the iexit
view results in select_views.sql. We aren't particularly interested
in the exact sorting behavior here, and this doesn't change the shape
of the generated plan, so it seems like a wash as far as the goals
of this test go.
This is in response to bug #14637 from Tomasz Kontusz. It doesn't
fully resolve his problem, because he also saw some diffs in the
create_index test. But other people have had issues with select_views
too, and this fix lets us drop the select_views_1.out variant expected
file altogether, which is a nice win from a maintenance standpoint.
Emre Hasegeli
Discussion: https://postgr.es/m/20170501000609.24360.24248@wrigleys.postgresql.org
Commit 9aa3c782c added code to allow CREATE TABLE/CREATE TYPE to not fail
when the desired type name conflicts with an autogenerated array type, by
dint of renaming the array type out of the way. But I (tgl) overlooked
that the same case arises in ALTER TABLE/TYPE RENAME. Fix that too.
Back-patch to all supported branches.
Report and patch by Vik Fearing, modified a bit by me
Discussion: https://postgr.es/m/0f4ade49-4f0b-a9a3-c120-7589f01d1eb8@2ndquadrant.com
Logical replication supports replicating between tables with different
column order. But this failed for the initial table sync because of a
logic error in how the column list for the internal COPY command was
composed. Fix that and also add a test.
Also fix a minor omission in the column name mapping cache. When
creating the mapping list, it would not skip locally dropped columns.
So if a remote column had the same name as a locally dropped
column (...pg.dropped...), then the expected error would not occur.
The cash_div_intX functions applied rint() to the result of the division.
That's not merely useless (because the result is already an integer) but
it causes precision loss for values larger than 2^52 or so, because of
the forced conversion to float8.
On the other hand, the cash_mul_fltX functions neglected to apply rint() to
their multiplication results, thus possibly causing off-by-one outputs.
Per C standard, arithmetic between any integral value and a float value is
performed in float format. Thus, cash_mul_flt4 and cash_div_flt4 produced
answers good to only about six digits, even when the float value is exact.
We can improve matters noticeably by widening the float inputs to double.
(It's tempting to consider using "long double" arithmetic if available,
but that's probably too much of a stretch for a back-patched fix.)
Also, document that cash_div_intX operators truncate rather than round.
Per bug #14663 from Richard Pistole. Back-patch to all supported branches.
Discussion: https://postgr.es/m/22403.1495223615@sss.pgh.pa.us
Otherwise, set_plan_refs() can get applied to the same list
multiple times through different references, leading to chaos.
Amit Langote, Dilip Kumar, and Robert Haas, reviewed by Ashutosh
Bapat. Original report by Sveinn Sveinsson.
Discussion: http://postgr.es/m/20170517141151.1435.79890@wrigleys.postgresql.org
This seemed like a good idea originally because there's no way to mark
a range partition as accepting NULL, but that now seems more like a
current limitation than something we want to lock down for all time.
For example, there's a proposal to add the notion of a default
partition which accepts all rows not otherwise routed, which directly
conflicts with the idea that a range-partitioned table should never
allow nulls anywhere. So let's change this while we still can, by
putting the NOT NULL test into the partition constraint instead of
changing the column properties.
Amit Langote and Robert Haas, reviewed by Amit Kapila
Discussion: http://postgr.es/m/8e2dd63d-c6fb-bb74-3c2b-ed6d63629c9d@lab.ntt.co.jp
When creating a subscription with slot_name = NONE, we failed to check
that also create_slot = false and enabled = false were set. This
created an invalid subscription and could later lead to a crash if a
NULL slot name was accessed. Add more checks around that for
robustness.
Reported-by: tushar <tushar.ahuja@enterprisedb.com>
Add some tests for parsing different option combinations. Fix some of
the resulting error messages for recent changes in option naming.
Author: Masahiko Sawada <sawada.mshk@gmail.com>
Modifying the permissions of a persistent file isn't really much nicer
than modifying its contents, even if git doesn't currently notice it.
Adjust the test script to make a copy and set the permissions of that
instead.
Michael Paquier, per a gripe from me. Back-patch to 9.5 where these
tests were introduced.
Discussion: https://postgr.es/m/14836.1494885946@sss.pgh.pa.us
The CommentStmt made by RebuildConstraintComment() has to pstrdup the
relation name, else it will contain a dangling pointer after that
relcache entry is flushed. (I'm less sure that pstrdup'ing conname
is necessary, but let's be safe.) Failure to do this leads to weird
errors or crashes, as reported by Marko Elezovic.
Bug introduced by commit e42375fc8, so back-patch to 9.5 as that was.
Fix by David Rowley, regression test by Michael Paquier
Discussion: https://postgr.es/m/DB6PR03MB30775D58E732D4EB0C13725B9AE00@DB6PR03MB3077.eurprd03.prod.outlook.com
In 1753b1b027035029c2a2a1649065762fafbf63f3, the pg_sequence system
catalog was introduced. This made sequence metadata changes
transactional, while the actual sequence values are still behaving
nontransactionally. This requires some refinement in how ALTER
SEQUENCE, which operates on both, locks the sequence and the catalog.
The main problems were:
- Concurrent ALTER SEQUENCE causes "tuple concurrently updated" error,
caused by updates to pg_sequence catalog.
- Sequence WAL writes and catalog updates are not protected by same
lock, which could lead to inconsistent recovery order.
- nextval() disregarding uncommitted ALTER SEQUENCE changes.
To fix, nextval() and friends now lock the sequence using
RowExclusiveLock instead of AccessShareLock. ALTER SEQUENCE locks the
sequence using ShareRowExclusiveLock. This means that nextval() and
ALTER SEQUENCE block each other, and ALTER SEQUENCE on the same sequence
blocks itself. (This was already the case previously for the OWNER TO,
RENAME, and SET SCHEMA variants.) Also, rearrange some code so that the
entire AlterSequence is protected by the lock on the sequence.
As an exception, use reduced locking for ALTER SEQUENCE ... RESTART.
Since that is basically a setval(), it does not require the full locking
of other ALTER SEQUENCE actions. So check whether we are only running a
RESTART and run with less locking if so.
Reviewed-by: Michael Paquier <michael.paquier@gmail.com>
Reported-by: Jason Petersen <jason@citusdata.com>
Reported-by: Andres Freund <andres@anarazel.de>
pg_stat_get_snapshot_timestamp() returns the timestamp seen in the "global"
stats file. Because pgstat_write_statsfiles() writes per-DB stats files
before the global file (or at least before renaming it into place), there
is a window where the test backend can see all the stats updates that
wait_for_stats() was checking for (all of which come from the per-DB file)
but also see the same global stats file it had seen at the start of the
test script. This results in a failure in only the "snapshot_newer" query,
as reported by a couple of buildfarm members recently.
I suspect that this ought to be back-patched. Commit 4e37b3e15 has
evidently increased the probability of this window getting hit, but
it's not apparent why it could not have been hit before. I'll refrain
for the moment though.
Commit 60690a6fe attempted to fix the wait_for_stats() function in this
test so that it would wait properly if the tenk2 scans were done in
parallel workers instead of the main session (typically as a consequence of
force_parallel_mode being turned on). However, we made it test for whether
the main session's actions had been reported by looking for inserts on
'trunc_stats_test'. This is the Wrong Thing, because those aren't the last
updates we expect the main session to do. As shown by recent failures on
buildfarm member frogmouth, it's entirely likely that the trunc_stats_test
updates will be reported in a separate message from later updates, which
means there can be a window in which wait_for_stats() will exit but not all
the updates we are expecting to see will have arrived. We should test for
the last updates we're expecting, namely those on 'trunc_stats_test4'.
Unfortunately, I doubt that this explains frogmouth's failures, because
there's no reason to believe that it's running the tenk2 queries in
parallel. Still, the test is wrong on its own terms, so fix and back-patch
to 9.6 where parallel query came in.
ALTER COLUMN TYPE on a column used by a statistics object fails since
commit 928c4de30, because the relevant switch in ATExecAlterColumnType
is unprepared for columns to have dependencies from OCLASS_STATISTIC_EXT
objects.
Although the existing types of extended statistics don't actually need us
to do any work for a column type change, it seems completely indefensible
that that assumption is hidden behind the failure of an unrelated module
to contain any code for the case. Hence, create and call an API function
in statscmds.c where the assumption can be explained, and where we could
add code to deal with the problem when it inevitably becomes real.
Also, the reason this wasn't handled before, neither for extended stats
nor for the last half-dozen new OCLASS kinds :-(, is that the default:
in that switch suppresses compiler warnings, allowing people to miss the
need to consider it when adding an OCLASS. We don't really need a default
because surely getObjectClass should only return valid values of the enum;
so remove it, and add the missed OCLASS entries where they should be.
Discussion: https://postgr.es/m/20170512221010.nglatgt5azzdxjlj@alvherre.pgsql
Consistently refer to such an entry as a "statistics object", not just
"statistics" or "extended statistics". Previously we had a mismash of
terms, accompanied by utter confusion as to whether the term was
singular or plural. That's not only grating (at least to the ear of
a native English speaker) but could be outright misleading, eg in error
messages that seemed to be referring to multiple objects where only one
could be meant.
This commit fixes the code and a lot of comments (though I may have
missed a few). I also renamed two new SQL functions,
pg_get_statisticsextdef -> pg_get_statisticsobjdef
pg_statistic_ext_is_visible -> pg_statistics_obj_is_visible
to conform better with this terminology.
I have not touched the SGML docs other than fixing those function
names; the docs certainly need work but it seems like a separable task.
Discussion: https://postgr.es/m/22676.1494557205@sss.pgh.pa.us
On faster machines, the overall runtime for running the core regression
tests is under twenty seconds these days, of which the hard-wired delays
in the stats test are a significant fraction. But on closer inspection,
it seems like we shouldn't need those.
The initial 2-second delay is there only to reduce the risk of the test's
stats messages not getting sent due to contention. But analysis of the
last ten years' worth of buildfarm runs shows no evidence that such
failures actually occur. (We do see failures that look like stats
messages not getting sent, particularly on Windows; but there is little
reason to believe that the initial delay reduces their frequency.)
The later 1-second delay is there to ensure that our session's stats
will have gotten sent. But we could also do that by starting a fresh
session, which takes well under 1 second even on very slow machines.
Hence, let's remove both delays and see what happens. The first delay
was the only test of pg_sleep_for() in the regression tests, but we can
move that responsibility into wait_for_stats().
Discussion: https://postgr.es/m/17795.1493869423@sss.pgh.pa.us
A stats object ought to have a dependency on each individual column
it reads, not the entire table. Doing this honestly lets us get rid
of the hard-wired logic in RemoveStatisticsExt, which seems to have
been misguidedly modeled on RemoveStatistics; and it will be far easier
to extend to multiple tables later.
Also, add overlooked dependency on owner, and make the dependency on
schema be NORMAL like every other such dependency.
There remains some unfinished work here, which is to allow statistics
objects to be extension members. That takes more effort than just
adding the dependency call, though, so I left it out for now.
initdb forced because this changes the set of pg_depend records that
should exist for a statistics object.
Discussion: https://postgr.es/m/22676.1494557205@sss.pgh.pa.us
Previously, we had the WITH clause in the middle of the command, where
you'd specify both generic options as well as statistic types. Few
people liked this, so this commit changes it to remove the WITH keyword
from that clause and makes it accept statistic types only. (We
currently don't have any generic options, but if we invent in the
future, we will gain a new WITH clause, probably at the end of the
command).
Also, the column list is now specified without parens, which makes the
whole command look more similar to a SELECT command. This change will
let us expand the command to supporting expressions (not just columns
names) as well as multiple tables and their join conditions.
Tom added lots of code comments and fixed some parts of the CREATE
STATISTICS reference page, too; more changes in this area are
forthcoming. He also fixed a potential problem in the alter_generic
regression test, reducing verbosity on a cascaded drop to avoid
dependency on message ordering, as we do in other tests.
Tom also closed a security bug: we documented that table ownership was
required in order to create a statistics object on it, but didn't
actually implement it.
Implement tab-completion for statistics objects. This can stand some
more improvement.
Authors: Alvaro Herrera, with lots of cleanup by Tom Lane
Discussion: https://postgr.es/m/20170420212426.ltvgyhnefvhixm6i@alvherre.pgsql
