This SQL standard functionality allows to aggregate data by different
GROUP BY clauses at once. Each grouping set returns rows with columns
grouped by in other sets set to NULL.
This could previously be achieved by doing each grouping as a separate
query, conjoined by UNION ALLs. Besides being considerably more concise,
grouping sets will in many cases be faster, requiring only one scan over
the underlying data.
The current implementation of grouping sets only supports using sorting
for input. Individual sets that share a sort order are computed in one
pass. If there are sets that don't share a sort order, additional sort &
aggregation steps are performed. These additional passes are sourced by
the previous sort step; thus avoiding repeated scans of the source data.
The code is structured in a way that adding support for purely using
hash aggregation or a mix of hashing and sorting is possible. Sorting
was chosen to be supported first, as it is the most generic method of
implementation.
Instead of, as in an earlier versions of the patch, representing the
chain of sort and aggregation steps as full blown planner and executor
nodes, all but the first sort are performed inside the aggregation node
itself. This avoids the need to do some unusual gymnastics to handle
having to return aggregated and non-aggregated tuples from underlying
nodes, as well as having to shut down underlying nodes early to limit
memory usage. The optimizer still builds Sort/Agg node to describe each
phase, but they're not part of the plan tree, but instead additional
data for the aggregation node. They're a convenient and preexisting way
to describe aggregation and sorting. The first (and possibly only) sort
step is still performed as a separate execution step. That retains
similarity with existing group by plans, makes rescans fairly simple,
avoids very deep plans (leading to slow explains) and easily allows to
avoid the sorting step if the underlying data is sorted by other means.
A somewhat ugly side of this patch is having to deal with a grammar
ambiguity between the new CUBE keyword and the cube extension/functions
named cube (and rollup). To avoid breaking existing deployments of the
cube extension it has not been renamed, neither has cube been made a
reserved keyword. Instead precedence hacking is used to make GROUP BY
cube(..) refer to the CUBE grouping sets feature, and not the function
cube(). To actually group by a function cube(), unlikely as that might
be, the function name has to be quoted.
Needs a catversion bump because stored rules may change.
Author: Andrew Gierth and Atri Sharma, with contributions from Andres Freund
Reviewed-By: Andres Freund, Noah Misch, Tom Lane, Svenne Krap, Tomas
Vondra, Erik Rijkers, Marti Raudsepp, Pavel Stehule
Discussion: CAOeZVidmVRe2jU6aMk_5qkxnB7dfmPROzM7Ur8JPW5j8Y5X-Lw@mail.gmail.com
Add a TABLESAMPLE clause to SELECT statements that allows
user to specify random BERNOULLI sampling or block level
SYSTEM sampling. Implementation allows for extensible
sampling functions to be written, using a standard API.
Basic version follows SQLStandard exactly. Usable
concrete use cases for the sampling API follow in later
commits.
Petr Jelinek
Reviewed by Michael Paquier and Simon Riggs
When this option is specified, a progress report is printed as each index
is reindexed.
Per discussion, we agreed on the following syntax for the extensibility of
the options.
REINDEX (flexible options) { INDEX | ... } name
Sawada Masahiko.
Reviewed by Robert Haas, Fabrízio Mello, Alvaro Herrera, Kyotaro Horiguchi,
Jim Nasby and me.
Discussion: CAD21AoA0pK3YcOZAFzMae+2fcc3oGp5zoRggDyMNg5zoaWDhdQ@mail.gmail.com
This feature lets user code inspect and take action on DDL events.
Whenever a ddl_command_end event trigger is installed, DDL actions
executed are saved to a list which can be inspected during execution of
a function attached to ddl_command_end.
The set-returning function pg_event_trigger_ddl_commands can be used to
list actions so captured; it returns data about the type of command
executed, as well as the affected object. This is sufficient for many
uses of this feature. For the cases where it is not, we also provide a
"command" column of a new pseudo-type pg_ddl_command, which is a
pointer to a C structure that can be accessed by C code. The struct
contains all the info necessary to completely inspect and even
reconstruct the executed command.
There is no actual deparse code here; that's expected to come later.
What we have is enough infrastructure that the deparsing can be done in
an external extension. The intention is that we will add some deparsing
code in a later release, as an in-core extension.
A new test module is included. It's probably insufficient as is, but it
should be sufficient as a starting point for a more complete and
future-proof approach.
Authors: Álvaro Herrera, with some help from Andres Freund, Ian Barwick,
Abhijit Menon-Sen.
Reviews by Andres Freund, Robert Haas, Amit Kapila, Michael Paquier,
Craig Ringer, David Steele.
Additional input from Chris Browne, Dimitri Fontaine, Stephen Frost,
Petr Jelínek, Tom Lane, Jim Nasby, Steven Singer, Pavel Stěhule.
Based on original work by Dimitri Fontaine, though I didn't use his
code.
Discussion:
https://www.postgresql.org/message-id/m2txrsdzxa.fsf@2ndQuadrant.frhttps://www.postgresql.org/message-id/20131108153322.GU5809@eldon.alvh.no-ip.orghttps://www.postgresql.org/message-id/20150215044814.GL3391@alvh.no-ip.org
The newly added ON CONFLICT clause allows to specify an alternative to
raising a unique or exclusion constraint violation error when inserting.
ON CONFLICT refers to constraints that can either be specified using a
inference clause (by specifying the columns of a unique constraint) or
by naming a unique or exclusion constraint. DO NOTHING avoids the
constraint violation, without touching the pre-existing row. DO UPDATE
SET ... [WHERE ...] updates the pre-existing tuple, and has access to
both the tuple proposed for insertion and the existing tuple; the
optional WHERE clause can be used to prevent an update from being
executed. The UPDATE SET and WHERE clauses have access to the tuple
proposed for insertion using the "magic" EXCLUDED alias, and to the
pre-existing tuple using the table name or its alias.
This feature is often referred to as upsert.
This is implemented using a new infrastructure called "speculative
insertion". It is an optimistic variant of regular insertion that first
does a pre-check for existing tuples and then attempts an insert. If a
violating tuple was inserted concurrently, the speculatively inserted
tuple is deleted and a new attempt is made. If the pre-check finds a
matching tuple the alternative DO NOTHING or DO UPDATE action is taken.
If the insertion succeeds without detecting a conflict, the tuple is
deemed inserted.
To handle the possible ambiguity between the excluded alias and a table
named excluded, and for convenience with long relation names, INSERT
INTO now can alias its target table.
Bumps catversion as stored rules change.
Author: Peter Geoghegan, with significant contributions from Heikki
Linnakangas and Andres Freund. Testing infrastructure by Jeff Janes.
Reviewed-By: Heikki Linnakangas, Andres Freund, Robert Haas, Simon Riggs,
Dean Rasheed, Stephen Frost and many others.
In commit 31eae6028e, some documents were not updated to show the new
capability; fix that. Also, the error message you get when CURRENT_USER
and SESSION_USER are used in a context that doesn't accept them could be
clearer about it being a problem only in those contexts; so add the
word "here".
Author: Kyotaro HORIGUCHI
His patch submission also included changes to GRANT/REVOKE, but those
seemed more controversial, so I left them out. We can reconsider these
changes later.
This provides a mechanism for specifying conversions between SQL data
types and procedural languages. As examples, there are transforms
for hstore and ltree for PL/Perl and PL/Python.
reviews by Pavel Stěhule and Andres Freund
FORCE option has been marked "obsolete" since very old version 7.4
but existed for backwards compatibility. Per discussion on pgsql-hackers,
we concluded that it's no longer worth keeping supporting the option.
Foreign tables can now be inheritance children, or parents. Much of the
system was already ready for this, but we had to fix a few things of
course, mostly in the area of planner and executor handling of row locks.
As side effects of this, allow foreign tables to have NOT VALID CHECK
constraints (and hence to accept ALTER ... VALIDATE CONSTRAINT), and to
accept ALTER SET STORAGE and ALTER SET WITH/WITHOUT OIDS. Continuing to
disallow these things would've required bizarre and inconsistent special
cases in inheritance behavior. Since foreign tables don't enforce CHECK
constraints anyway, a NOT VALID one is a complete no-op, but that doesn't
mean we shouldn't allow it. And it's possible that some FDWs might have
use for SET STORAGE or SET WITH OIDS, though doubtless they will be no-ops
for most.
An additional change in support of this is that when a ModifyTable node
has multiple target tables, they will all now be explicitly identified
in EXPLAIN output, for example:
Update on pt1 (cost=0.00..321.05 rows=3541 width=46)
Update on pt1
Foreign Update on ft1
Foreign Update on ft2
Update on child3
-> Seq Scan on pt1 (cost=0.00..0.00 rows=1 width=46)
-> Foreign Scan on ft1 (cost=100.00..148.03 rows=1170 width=46)
-> Foreign Scan on ft2 (cost=100.00..148.03 rows=1170 width=46)
-> Seq Scan on child3 (cost=0.00..25.00 rows=1200 width=46)
This was done mainly to provide an unambiguous place to attach "Remote SQL"
fields, but it is useful for inherited updates even when no foreign tables
are involved.
Shigeru Hanada and Etsuro Fujita, reviewed by Ashutosh Bapat and Kyotaro
Horiguchi, some additional hacking by me
We were involving the parser too much in setting up initial vacuuming
parameters. This patch moves that responsibility elsewhere to simplify
code, and also to make future additions easier. To do this, create a
new struct VacuumParams which is filled just prior to vacuum execution,
instead of at parse time; for user-invoked vacuuming this is set up in a
new function ExecVacuum, while autovacuum sets it up by itself.
While at it, add a new member VACOPT_SKIPTOAST to enum VacuumOption,
only set by autovacuum, which is used to disable vacuuming of the toast
table instead of the old do_toast parameter; this relieves the argument
list of vacuum() and some callees a bit. This partially makes up for
having added more arguments in an effort to avoid having autovacuum from
constructing a VacuumStmt parse node.
Author: Michael Paquier. Some tweaks by Álvaro
Reviewed by: Robert Haas, Stephen Frost, Álvaro Herrera
In the spirit of 890192e99a and 4464303405f: have get_object_address
understand individual pg_amop and pg_amproc objects. There is no way to
refer to such objects directly in the grammar -- rather, they are almost
always considered an integral part of the opfamily that contains them.
(The only case that deals with them individually is ALTER OPERATOR
FAMILY ADD/DROP, which carries the opfamily address separately and thus
does not need it to be part of each added/dropped element's address.)
In event triggers it becomes possible to become involved with individual
amop/amproc elements, and this commit enables pg_get_object_address to
do so as well.
To make the overall coding simpler, this commit also slightly changes
the get_object_address representation for opclasses and opfamilies:
instead of having the AM name in the objargs array, I moved it as the
first element of the objnames array. This enables the new code to use
objargs for the type names used by pg_amop and pg_amproc.
Reviewed by: Stephen Frost
While the SQL standard is pretty vague on the overall topic of operator
precedence (because it never presents a unified BNF for all expressions),
it does seem reasonable to conclude from the spec for <boolean value
expression> that OR has the lowest precedence, then AND, then NOT, then IS
tests, then the six standard comparison operators, then everything else
(since any non-boolean operator in a WHERE clause would need to be an
argument of one of these).
We were only sort of on board with that: most notably, while "<" ">" and
"=" had properly low precedence, "<=" ">=" and "<>" were treated as generic
operators and so had significantly higher precedence. And "IS" tests were
even higher precedence than those, which is very clearly wrong per spec.
Another problem was that "foo NOT SOMETHING bar" constructs, such as
"x NOT LIKE y", were treated inconsistently because of a bison
implementation artifact: they had the documented precedence with respect
to operators to their right, but behaved like NOT (i.e., very low priority)
with respect to operators to their left.
Fixing the precedence issues is just a small matter of rearranging the
precedence declarations in gram.y, except for the NOT problem, which
requires adding an additional lookahead case in base_yylex() so that we
can attach a different token precedence to NOT LIKE and allied two-word
operators.
The bulk of this patch is not the bug fix per se, but adding logic to
parse_expr.c to allow giving warnings if an expression has changed meaning
because of these precedence changes. These warnings are off by default
and are enabled by the new GUC operator_precedence_warning. It's believed
that very few applications will be affected by these changes, but it was
agreed that a warning mechanism is essential to help debug any that are.
SQL has standardized on => as the use of to specify named parameters,
and we've wanted for many years to support the same syntax ourselves,
but this has been complicated by the possible use of => as an operator
name. In PostgreSQL 9.0, we began emitting a warning when an operator
named => was defined, and in PostgreSQL 9.2, we stopped shipping a
=>(text, text) operator as part of hstore. By the time the next major
version of PostgreSQL is released, => will have been deprecated for a
full five years, so hopefully there won't be too many people still
relying on it. We continue to support := for compatibility with
previous PostgreSQL releases.
Pavel Stehule, reviewed by Petr Jelinek, with a few documentation
tweaks by me.
Commands such as ALTER USER, ALTER GROUP, ALTER ROLE, GRANT, and the
various ALTER OBJECT / OWNER TO, as well as ad-hoc clauses related to
roles such as the AUTHORIZATION clause of CREATE SCHEMA, the FOR clause
of CREATE USER MAPPING, and the FOR ROLE clause of ALTER DEFAULT
PRIVILEGES can now take the keywords CURRENT_USER and SESSION_USER as
user specifiers in place of an explicit user name.
This commit also fixes some quite ugly handling of special standards-
mandated syntax in CREATE USER MAPPING, which in particular would fail
to work in presence of a role named "current_user".
The special role specifiers PUBLIC and NONE also have more consistent
handling now.
Also take the opportunity to add location tracking to user specifiers.
Authors: Kyotaro Horiguchi. Heavily reworked by Álvaro Herrera.
Reviewed by: Rushabh Lathia, Adam Brightwell, Marti Raudsepp.
There are a couple of places in our grammar that fail to be strict LALR(1),
by requiring more than a single token of lookahead to decide what to do.
Up to now we've dealt with that by using a filter between the lexer and
parser that merges adjacent tokens into one in the places where two tokens
of lookahead are necessary. But that creates a number of user-visible
anomalies, for instance that you can't name a CTE "ordinality" because
"WITH ordinality AS ..." triggers folding of WITH and ORDINALITY into one
token. I realized that there's a better way.
In this patch, we still do the lookahead basically as before, but we never
merge the second token into the first; we replace just the first token by
a special lookahead symbol when one of the lookahead pairs is seen.
This requires a couple extra productions in the grammar, but it involves
fewer special tokens, so that the grammar tables come out a bit smaller
than before. The filter logic is no slower than before, perhaps a bit
faster.
I also fixed the filter logic so that when backing up after a lookahead,
the current token's terminator is correctly restored; this eliminates some
weird behavior in error message issuance, as is shown by the one change in
existing regression test outputs.
I believe that this patch entirely eliminates odd behaviors caused by
lookahead for WITH. It doesn't really improve the situation for NULLS
followed by FIRST/LAST unfortunately: those sequences still act like a
reserved word, even though there are cases where they should be seen as two
ordinary identifiers, eg "SELECT nulls first FROM ...". I experimented
with additional grammar hacks but couldn't find any simple solution for
that. Still, this is better than before, and it seems much more likely
that we *could* somehow solve the NULLS case on the basis of this filter
behavior than the previous one.
Use a different A_Expr_Kind for LIKE/ILIKE/SIMILAR TO constructs, so that
they can be distinguished from direct invocation of the underlying
operators. Also, postpone selection of the operator name when transforming
"x IN (select)" to "x = ANY (select)", so that those syntaxes can be told
apart at parse analysis time.
I had originally thought I'd also have to do something special for the
syntaxes IS NOT DISTINCT FROM, IS NOT DOCUMENT, and x NOT IN (SELECT...),
which the grammar translates as though they were NOT (construct).
On reflection though, we can distinguish those cases reliably by noting
whether the parse location shown for the NOT is the same as for its child
node. This only requires tweaking the parse locations for NOT IN, which
I've done here.
These changes should have no effect outside the parser; they're just in
support of being able to give accurate warnings for planned operator
precedence changes.
We did not need a location tag on NullTest or BooleanTest before, because
no error messages referred directly to their locations. That's planned
to change though, so add these fields in a separate housekeeping commit.
Catversion bump because stored rules may change.
transformExpr() has for many years had provisions to do nothing when
applied to an already-transformed expression tree. However, this was
always ugly and of dubious reliability, so we'd be much better off without
it. The primary historical reason for it was that gram.y sometimes
returned multiple links to the same subexpression, which is no longer true
as of my BETWEEN fixes. We'd also grown some lazy hacks in CREATE TABLE
LIKE (failing to distinguish between raw and already-transformed index
specifications) and one or two other places.
This patch removes the need for and support for re-transforming already
transformed expressions. The index case is dealt with by adding a flag
to struct IndexStmt to indicate that it's already been transformed;
which has some benefit anyway in that tablecmds.c can now Assert that
transformation has happened rather than just assuming. The other main
reason was some rather sloppy code for array type coercion, which can
be fixed (and its performance improved too) by refactoring.
I did leave transformJoinUsingClause() still constructing expressions
containing untransformed operator nodes being applied to Vars, so that
transformExpr() still has to allow Var inputs. But that's a much narrower,
and safer, special case than before, since Vars will never appear in a raw
parse tree, and they don't have any substructure to worry about.
In passing fix some oversights in the patch that added CREATE INDEX
IF NOT EXISTS (missing processing of IndexStmt.if_not_exists). These
appear relatively harmless, but still sloppy coding practice.
Previously, gram.y itself converted BETWEEN into AND (or AND/OR) nests of
expression comparisons. This was always as bogus as could be, but fixing
it hasn't risen to the top of the to-do list. The present patch invents an
A_Expr representation for BETWEEN expressions, and does the expansion to
comparison trees in parse_expr.c which is at least a slightly saner place
to be doing semantic conversions. There should be no change in the post-
parse-analysis results.
This does nothing for the semantic issues with BETWEEN (dubious connection
to btree-opclass semantics, and multiple evaluation of possibly volatile
subexpressions) ... but it's a necessary preliminary step before we could
fix any of that. The main immediate benefit is that preserving BETWEEN as
an identifiable raw-parse-tree construct will enable better error messages.
While at it, fix the code so that multiply-referenced subexpressions are
physically duplicated before being passed through transformExpr(). This
gets rid of one of the principal reasons why transformExpr() has
historically had to allow already-processed input.
Commit 3f88672a4 neglected to update the AlterExtensionContentsStmt
production in the grammar to use TypeName to represent types when
passing objects to get_object_address.
Reported as a pg_upgrade failure by Jeff Janes.
In COMMENT, DROP, SECURITY LABEL, and the new pg_get_object_address
function, we were representing types as a list of names, same as other
objects; but types are special objects that require their own
representation to be totally accurate. In the original COMMENT code we
had a note about fixing it which was lost in the course of c10575ff00.
Change all those places to use TypeName instead, as suggested by that
comment.
Right now the original coding doesn't cause any bugs, so no backpatch.
It is more problematic for proposed future code that operate with object
addresses from the SQL interface; type details such as array-ness are
lost when working with the degraded representation.
Thanks to Petr Jelínek and Dimitri Fontaine for offlist help on finding
a solution to a shift/reduce grammar conflict.
Apart from enabling comments on domain constraints, this enables a
future project to replicate object dropping to remote servers: with the
current mechanism there's no way to distinguish between the two types of
constraints, so there's no way to know what to drop.
Also added support for the domain constraint comments in psql's \dd and
pg_dump.
Catalog version bumped due to the change in ObjectType enum.
As pointed out by Robert, we should really have named pg_rowsecurity
pg_policy, as the objects stored in that catalog are policies. This
patch fixes that and updates the column names to start with 'pol' to
match the new catalog name.
The security consideration for COPY with row level security, also
pointed out by Robert, has also been addressed by remembering and
re-checking the OID of the relation initially referenced during COPY
processing, to make sure it hasn't changed under us by the time we
finish planning out the query which has been built.
Robert and Alvaro also commented on missing OCLASS and OBJECT entries
for POLICY (formerly ROWSECURITY or POLICY, depending) in various
places. This patch fixes that too, which also happens to add the
ability to COMMENT on policies.
In passing, attempt to improve the consistency of messages, comments,
and documentation as well. This removes various incarnations of
'row-security', 'row-level security', 'Row-security', etc, in favor
of 'policy', 'row level security' or 'row_security' as appropriate.
Happy Thanksgiving!
interval precision can only be specified after the "interval" keyword if
no units are specified.
Previously we incorrectly checked the units to see if the precision was
legal, causing confusion.
Report by Alvaro Herrera
This clause changes the behavior of SELECT locking clauses in the
presence of locked rows: instead of causing a process to block waiting
for the locks held by other processes (or raise an error, with NOWAIT),
SKIP LOCKED makes the new reader skip over such rows. While this is not
appropriate behavior for general purposes, there are some cases in which
it is useful, such as queue-like tables.
Catalog version bumped because this patch changes the representation of
stored rules.
Reviewed by Craig Ringer (based on a previous attempt at an
implementation by Simon Riggs, who also provided input on the syntax
used in the current patch), David Rowley, and Álvaro Herrera.
Author: Thomas Munro
Building on the updatable security-barrier views work, add the
ability to define policies on tables to limit the set of rows
which are returned from a query and which are allowed to be added
to a table. Expressions defined by the policy for filtering are
added to the security barrier quals of the query, while expressions
defined to check records being added to a table are added to the
with-check options of the query.
New top-level commands are CREATE/ALTER/DROP POLICY and are
controlled by the table owner. Row Security is able to be enabled
and disabled by the owner on a per-table basis using
ALTER TABLE .. ENABLE/DISABLE ROW SECURITY.
Per discussion, ROW SECURITY is disabled on tables by default and
must be enabled for policies on the table to be used. If no
policies exist on a table with ROW SECURITY enabled, a default-deny
policy is used and no records will be visible.
By default, row security is applied at all times except for the
table owner and the superuser. A new GUC, row_security, is added
which can be set to ON, OFF, or FORCE. When set to FORCE, row
security will be applied even for the table owner and superusers.
When set to OFF, row security will be disabled when allowed and an
error will be thrown if the user does not have rights to bypass row
security.
Per discussion, pg_dump sets row_security = OFF by default to ensure
that exports and backups will have all data in the table or will
error if there are insufficient privileges to bypass row security.
A new option has been added to pg_dump, --enable-row-security, to
ask pg_dump to export with row security enabled.
A new role capability, BYPASSRLS, which can only be set by the
superuser, is added to allow other users to be able to bypass row
security using row_security = OFF.
Many thanks to the various individuals who have helped with the
design, particularly Robert Haas for his feedback.
Authors include Craig Ringer, KaiGai Kohei, Adam Brightwell, Dean
Rasheed, with additional changes and rework by me.
Reviewers have included all of the above, Greg Smith,
Jeff McCormick, and Robert Haas.
This patch allows us to execute ALTER SYSTEM RESET command to
remove the configuration entry from postgresql.auto.conf.
Vik Fearing, reviewed by Amit Kapila and me.
This enables changing permanent (logged) tables to unlogged and
vice-versa.
(Docs for ALTER TABLE / SET TABLESPACE got shuffled in an order that
hopefully makes more sense than the original.)
Author: Fabrízio de Royes Mello
Reviewed by: Christoph Berg, Andres Freund, Thom Brown
Some tweaking by Álvaro Herrera
As 'ALTER TABLESPACE .. MOVE ALL' really didn't change the tablespace
but instead changed objects inside tablespaces, it made sense to
rework the syntax and supporting functions to operate under the
'ALTER (TABLE|INDEX|MATERIALIZED VIEW)' syntax and to be in
tablecmds.c.
Pointed out by Alvaro, who also suggested the new syntax.
Back-patch to 9.4.
This command provides an automated way to create foreign table definitions
that match remote tables, thereby reducing tedium and chances for error.
In this patch, we provide the necessary core-server infrastructure and
implement the feature fully in the postgres_fdw foreign-data wrapper.
Other wrappers will throw a "feature not supported" error until/unless
they are updated.
Ronan Dunklau and Michael Paquier, additional work by me
Most of the existing option names are keywords anyway, but we can get rid
of LC_COLLATE and LC_CTYPE as keywords known to the lexer/grammar. This
immediately reduces the size of the grammar tables by about 8KB, and will
save more when we add additional CREATE/ALTER DATABASE options in future.
A side effect of the implementation is that the CONNECTION LIMIT option
can now also be spelled CONNECTION_LIMIT. We choose not to document this,
however.
Vik Fearing, based on a suggestion by me; reviewed by Pavel Stehule
This SQL-standard feature allows a sub-SELECT yielding multiple columns
(but only one row) to be used to compute the new values of several columns
to be updated. While the same results can be had with an independent
sub-SELECT per column, such a workaround can require a great deal of
duplicated computation.
The standard actually says that the source for a multi-column assignment
could be any row-valued expression. The implementation used here is
tightly tied to our existing sub-SELECT support and can't handle other
cases; the Bison grammar would have some issues with them too. However,
I don't feel too bad about this since other cases can be converted into
sub-SELECTs. For instance, "SET (a,b,c) = row_valued_function(x)" could
be written "SET (a,b,c) = (SELECT * FROM row_valued_function(x))".
Since most of the system thinks AND and OR are N-argument expressions
anyway, let's have the grammar generate a representation of that form when
dealing with input like "x AND y AND z AND ...", rather than generating
a deeply-nested binary tree that just has to be flattened later by the
planner. This avoids stack overflow in parse analysis when dealing with
queries having more than a few thousand such clauses; and in any case it
removes some rather unsightly inconsistencies, since some parts of parse
analysis were generating N-argument ANDs/ORs already.
It's still possible to get a stack overflow with weirdly parenthesized
input, such as "x AND (y AND (z AND ( ... )))", but such cases are not
mainstream usage. The maximum depth of parenthesization is already
limited by Bison's stack in such cases, anyway, so that the limit is
probably fairly platform-independent.
Patch originally by Gurjeet Singh, heavily revised by me
This reverts commit 45b7abe59e.
It turns out that the %name-prefix syntax without "=" does not work
at all in pre-2.4 Bison. We are not prepared to make such a large
jump in minimum required Bison version just to suppress a warning
message in a version hardly any developers are using yet.
When 3.0 gets more popular, we'll figure out a way to deal with this.
In the meantime, BISONFLAGS=-Wno-deprecated is recommendable for
anyone using 3.0 who doesn't want to see the warning.
%name-prefix doesn't use an "=" sign according to the Bison docs, but it
silently accepted one anyway, until Bison 3.0. This was originally a
typo of mine in commit 012abebab1, and we
seem to have slavishly copied the error into all the other grammar files.
Per report from Vik Fearing; analysis by Peter Eisentraut.
Back-patch to all active branches, since somebody might try to build
a back branch with up-to-date tools.
Given that ALTER TABLESPACE has moved on from just existing for
general purpose rename/owner changes, it deserves its own top-level
production in the grammar. This also cleans up the RenameStmt to
only ever be used for actual RENAMEs again- it really wasn't
appropriate to hide non-RENAME productions under there.
Noted by Alvaro.
This forces an input field containing the quoted null string to be
returned as a NULL. Without this option, only unquoted null strings
behave this way. This helps where some CSV producers insist on quoting
every field, whether or not it is needed. The option takes a list of
fields, and only applies to those columns. There is an equivalent
column-level option added to file_fdw.
Ian Barwick, with some tweaking by Andrew Dunstan, reviewed by Payal
Singh.
The SQL standard says that OVERLAPS should have a two-element row
constructor on each side. The original coding of OVERLAPS support in
our grammar attempted to extend that by allowing a single-element row
constructor, which it internally duplicated ... or tried to, anyway.
But that code has certainly not worked since our List infrastructure was
rewritten in 2004, and I'm none too sure it worked before that. As it
stands, it ends up building a List that includes itself, leading to
assorted undesirable behaviors later in the parser.
Even if it worked as intended, it'd be a bit evil because of the
possibility of duplicate evaluation of a volatile function that the user
had written only once. Given the lack of documentation, test cases, or
complaints, let's just get rid of the idea and only support the standard
syntax.
While we're at it, improve the error cursor positioning for the
wrong-number-of-arguments errors, and inline the makeOverlaps() function
since it's only called in one place anyway.
Per bug #9227 from Joshua Yanovski. Initial patch by Joshua Yanovski,
extended a bit by me.
Previously we were piggybacking on transaction ID parameters to freeze
multixacts; but since there isn't necessarily any relationship between
rates of Xid and multixact consumption, this turns out not to be a good
idea.
Therefore, we now have multixact-specific freezing parameters:
vacuum_multixact_freeze_min_age: when to remove multis as we come across
them in vacuum (default to 5 million, i.e. early in comparison to Xid's
default of 50 million)
vacuum_multixact_freeze_table_age: when to force whole-table scans
instead of scanning only the pages marked as not all visible in
visibility map (default to 150 million, same as for Xids). Whichever of
both which reaches the 150 million mark earlier will cause a whole-table
scan.
autovacuum_multixact_freeze_max_age: when for cause emergency,
uninterruptible whole-table scans (default to 400 million, double as
that for Xids). This means there shouldn't be more frequent emergency
vacuuming than previously, unless multixacts are being used very
rapidly.
Backpatch to 9.3 where multixacts were made to persist enough to require
freezing. To avoid an ABI break in 9.3, VacuumStmt has a couple of
fields in an unnatural place, and StdRdOptions is split in two so that
the newly added fields can go at the end.
Patch by me, reviewed by Robert Haas, with additional input from Andres
Freund and Tom Lane.
Add the ability to specify the objects to move by who those objects are
owned by (as relowner) and change ALL to mean ALL objects. This
makes the command always operate against a well-defined set of objects
and not have the objects-to-be-moved based on the role of the user
running the command.
Per discussion with Simon and Tom.
A while back, 2c92edad48 allowed
type_func_name_keywords to be used in more places, including role
identifiers. Unfortunately, that commit missed out on cases where
name_list was used for lists-of-roles, eg: for DROP ROLE. This
resulted in the unfortunate situation that you could CREATE a role
with a type_func_name_keywords-allowed identifier, but not DROP it
(directly- ALTER could be used to rename it to something which
could be DROP'd).
This extends allowing type_func_name_keywords to places where role
lists can be used.
Back-patch to 9.0, as 2c92edad48 was.
Andres Freund
Simon Riggs
Fujii Masao
Alvaro Herrera
Peter Eisentraut
Heikki Linnakangas
Bruce Momjian
Tom Lane
Robert Haas
Andrew Dunstan
Stephen Frost