Commit Graph

268 Commits

Author SHA1 Message Date
Heikki Linnakangas c5f42daa60 Misc documentation fixes.
- Misc grammar and punctuation fixes.

- Stylistic cleanup: use spaces between function arguments and JSON fields
  in examples. For example "foo(a,b)" -> "foo(a, b)". Add semicolon after
  last END in a few PL/pgSQL examples that were missing them.

- Make sentence that talked about "..." and ".." operators more clear,
  by avoiding to end the sentence with "..". That makes it look the same
  as "..."

- Fix syntax description for HAVING: HAVING conditions cannot be repeated

Patch by Justin Pryzby, per Yaroslav Schekin's report. Backpatch to all
supported versions, to the extent that the patch applies easily.

Discussion: https://www.postgresql.org/message-id/20201005191922.GE17626%40telsasoft.com
2020-10-19 19:28:54 +03:00
Peter Eisentraut 2453ea1422 Support for OUT parameters in procedures
Unlike for functions, OUT parameters for procedures are part of the
signature.  Therefore, they have to be listed in pg_proc.proargtypes
as well as mentioned in ALTER PROCEDURE and DROP PROCEDURE.

Reviewed-by: Andrew Dunstan <andrew.dunstan@2ndquadrant.com>
Reviewed-by: Pavel Stehule <pavel.stehule@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/2b8490fe-51af-e671-c504-47359dc453c5@2ndquadrant.com
2020-10-05 09:21:43 +02:00
Peter Eisentraut 9081bddbd7 Improve <xref> vs. <command> formatting in the documentation
SQL commands are generally marked up as <command>, except when a link
to a reference page is used using <xref>.  But the latter doesn't
create monospace markup, so this looks strange especially when a
paragraph contains a mix of links and non-links.

We considered putting <command> in the <refentrytitle> on the target
side, but that creates some formatting side effects elsewhere.
Generally, it seems safer to solve this on the link source side.

We can't put the <xref> inside the <command>; the DTD doesn't allow
this.  DocBook 5 would allow the <command> to have the linkend
attribute itself, but we are not there yet.

So to solve this for now, convert the <xref>s to <link> plus
<command>.  This gives the correct look and also gives some more
flexibility what we can put into the link text (e.g., subcommands or
other clauses).  In the future, these could then be converted to
DocBook 5 style.

I haven't converted absolutely all xrefs to SQL command reference
pages, only those where we care about the appearance of the link text
or where it was otherwise appropriate to make the appearance match a
bit better.  Also in some cases, the links where repetitive, so in
those cases the links where just removed and replaced by a plain
<command>.  In cases where we just want the link and don't
specifically care about the generated link text (typically phrased
"for further information see <xref ...>") the xref is kept.

Reported-by: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>
Discussion: https://www.postgresql.org/message-id/flat/87o8pco34z.fsf@wibble.ilmari.org
2020-10-03 16:40:02 +02:00
Peter Eisentraut 7f055fba3f doc: Fix up title case
This fixes some instances that were missed in earlier processings and
that now look a bit strange because they are inconsistent with nearby
titles.
2020-08-25 07:29:05 +02:00
Michael Paquier 8cea55e99b doc: Fix incorrect reference to textout in plpgsql examples
This error has survived for 22 years, and has been introduced by
da63386.

Reported-by: Erwin Brandstetter
Discussion: https://postgr.es/m/CAGHENJ57wogGOvGXo5LgWYcqswxafLck8ELqHDR+zrkTPgs_OQ@mail.gmail.com
Backpatch-through: 9.5
2020-07-05 19:35:56 +09:00
Bruce Momjian 0dd1eb3aea doc: remove xreflabels from commits 75fcdd2ae2 and 85af628da5
xreflabels prevent references to the chapter numbers of sections id's.
It should only be used in specific cases.

Discussion: https://postgr.es/m/8315c0ca-7758-8823-fcb6-f37f9413e6b6@2ndquadrant.com

Backpatch-through: 9.5
2020-06-11 18:19:25 -04:00
Bruce Momjian 75fcdd2ae2 doc: add missing xreflabels to the main docs (not refs)
Add missing xreflabels for index types, geqo, libpq, spi, server-side
languages, ecpg, and vaacuumlo.

Backpatch-through: 9.5
2020-05-15 12:05:43 -04:00
Tom Lane f21599311e Doc: further fooling-about with rendering of tables in PDF output.
I concluded that we really just ought to force all tables in PDF output
to default to "left" alignment (instead of "justify"); that is what the
HTML toolchain does and that's what most people have been designing the
tables to look good with.  There are few if any places where "justify"
produces better-looking output, and there are many where it looks
horrible.  So change stylesheet-fo.xsl to make that true.

Also tweak column widths in a few more tables to make them look better
and avoid "exceed the available area" warnings.  This commit fixes
basically everything that can be fixed through that approach.  The
remaining tables that give warnings either are scheduled for redesign
as per recent discussions, or need a fundamental rethink because they
Just Don't Work in a narrow view.
2020-05-06 12:23:54 -04:00
Tom Lane 24e2885ee3 Introduce "anycompatible" family of polymorphic types.
This patch adds the pseudo-types anycompatible, anycompatiblearray,
anycompatiblenonarray, and anycompatiblerange.  They work much like
anyelement, anyarray, anynonarray, and anyrange respectively, except
that the actual input values need not match precisely in type.
Instead, if we can find a common supertype (using the same rules
as for UNION/CASE type resolution), then the parser automatically
promotes the input values to that type.  For example,
"myfunc(anycompatible, anycompatible)" can match a call with one
integer and one bigint argument, with the integer automatically
promoted to bigint.  With anyelement in the definition, the user
would have had to cast the integer explicitly.

The new types also provide a second, independent set of type variables
for function matching; thus with "myfunc(anyelement, anyelement,
anycompatible) returns anycompatible" the first two arguments are
constrained to be the same type, but the third can be some other
type, and the result has the type of the third argument.  The need
for more than one set of type variables was foreseen back when we
first invented the polymorphic types, but we never did anything
about it.

Pavel Stehule, revised a bit by me

Discussion: https://postgr.es/m/CAFj8pRDna7VqNi8gR+Tt2Ktmz0cq5G93guc3Sbn_NVPLdXAkqA@mail.gmail.com
2020-03-19 11:43:11 -04:00
Peter Eisentraut cbe63d02d0 doc: Use proper em and en dashes 2019-10-25 20:39:41 +02:00
Amit Kapila 9b3c8f07ff Doc: Update PL/pgSQL sample function in plpgsql.sgml.
The example used to explain 'Looping Through Query Results' uses
pseudo-materialized views.  Replace it with a more up-to-date example
which does the same thing with actual materialized views, which have
been available since PostgreSQL 9.3.

In the passing, change '%' as format specifier instead of '%s' as is used
in other examples in plpgsql.sgml.

Reported-by: Ian Barwick
Author: Ian Barwick
Reviewed-by: Amit Kapila
Backpatch-through: 9.4
Discussion: https://postgr.es/m/9a70d393-7904-4918-c97c-649f6d114b6a@2ndquadrant.com
2019-09-12 13:15:51 +05:30
Peter Eisentraut 8e929a4667 doc: Clean up title case use
Note: Following existing practice, titles of formalpara and step are
not titlecased.
2019-09-08 10:27:29 +02:00
Michael Paquier 66bde49d96 Fix inconsistencies and typos in the tree, take 10
This addresses some issues with unnecessary code comments, fixes various
typos in docs and comments, and removes some orphaned structures and
definitions.

Author: Alexander Lakhin
Discussion: https://postgr.es/m/9aabc775-5494-b372-8bcb-4dfc0bd37c68@gmail.com
2019-08-13 13:53:41 +09:00
Peter Eisentraut 02daece4ab Fix grammar in error message 2019-05-09 09:16:59 +02:00
Peter Eisentraut 280a408b48 Transaction chaining
Add command variants COMMIT AND CHAIN and ROLLBACK AND CHAIN, which
start new transactions with the same transaction characteristics as the
just finished one, per SQL standard.

Support for transaction chaining in PL/pgSQL is also added.  This
functionality is especially useful when running COMMIT in a loop in
PL/pgSQL.

Reviewed-by: Fabien COELHO <coelho@cri.ensmp.fr>
Discussion: https://www.postgresql.org/message-id/flat/28536681-324b-10dc-ade8-ab46f7645a5a@2ndquadrant.com
2019-03-24 11:33:02 +01:00
Tom Lane 59029b6fb7 Update docs & tests to reflect that unassigned OLD/NEW are now NULL.
For a long time, plpgsql has allowed trigger functions to parse
references to OLD and NEW even if the current trigger event type didn't
assign a value to one or the other variable; but actually executing such
a reference would fail.  The v11 changes to use "expanded records" for
DTYPE_REC variables changed the behavior so that the unassigned variable
now reads as a null composite value.  While this behavioral change was
more or less unintentional, it seems that leaving it like this is better
than adding code and complexity to be bug-compatible with the old way.
The change doesn't break any code that worked before, and it eliminates
a gotcha that often required extra code to work around.

Hence, update the docs to say that these variables are "null" not
"unassigned" when not relevant to the event type.  And add a regression
test covering the behavior, so that we'll notice if we ever break it
again.

Per report from Kristjan Tammekivi.

Discussion: https://postgr.es/m/CAABK7uL-uC9ZxKBXzo_68pKt7cECfNRv+c35CXZpjq6jCAzYYA@mail.gmail.com
2019-01-09 11:35:14 -05:00
Tom Lane eeee62d805 Doc: make cross-reference to format() function more specific.
Jeff Janes

Discussion: https://postgr.es/m/CAMkU=1w7Tn2M9BhK+rt8Shtz1AkU+ty7By8gj5C==z65=U4vyQ@mail.gmail.com
2018-12-07 10:41:26 -05:00
Bruce Momjian 7a9d6779d9 doc: fix wording for plpgsql, add "and"
Reported-by: Anthony Greene

Discussion: https://postgr.es/m/CAPRNmnsSZ4QL75FUjcS8ND_oV+WjgyPbZ4ch2RUwmW6PWzF38w@mail.gmail.com

Backpatch-through: 9.4
2018-11-26 19:41:29 -05:00
Andres Freund 578b229718 Remove WITH OIDS support, change oid catalog column visibility.
Previously tables declared WITH OIDS, including a significant fraction
of the catalog tables, stored the oid column not as a normal column,
but as part of the tuple header.

This special column was not shown by default, which was somewhat odd,
as it's often (consider e.g. pg_class.oid) one of the more important
parts of a row.  Neither pg_dump nor COPY included the contents of the
oid column by default.

The fact that the oid column was not an ordinary column necessitated a
significant amount of special case code to support oid columns. That
already was painful for the existing, but upcoming work aiming to make
table storage pluggable, would have required expanding and duplicating
that "specialness" significantly.

WITH OIDS has been deprecated since 2005 (commit ff02d0a05280e0).
Remove it.

Removing includes:
- CREATE TABLE and ALTER TABLE syntax for declaring the table to be
  WITH OIDS has been removed (WITH (oids[ = true]) will error out)
- pg_dump does not support dumping tables declared WITH OIDS and will
  issue a warning when dumping one (and ignore the oid column).
- restoring an pg_dump archive with pg_restore will warn when
  restoring a table with oid contents (and ignore the oid column)
- COPY will refuse to load binary dump that includes oids.
- pg_upgrade will error out when encountering tables declared WITH
  OIDS, they have to be altered to remove the oid column first.
- Functionality to access the oid of the last inserted row (like
  plpgsql's RESULT_OID, spi's SPI_lastoid, ...) has been removed.

The syntax for declaring a table WITHOUT OIDS (or WITH (oids = false)
for CREATE TABLE) is still supported. While that requires a bit of
support code, it seems unnecessary to break applications / dumps that
do not use oids, and are explicit about not using them.

The biggest user of WITH OID columns was postgres' catalog. This
commit changes all 'magic' oid columns to be columns that are normally
declared and stored. To reduce unnecessary query breakage all the
newly added columns are still named 'oid', even if a table's column
naming scheme would indicate 'reloid' or such.  This obviously
requires adapting a lot code, mostly replacing oid access via
HeapTupleGetOid() with access to the underlying Form_pg_*->oid column.

The bootstrap process now assigns oids for all oid columns in
genbki.pl that do not have an explicit value (starting at the largest
oid previously used), only oids assigned later by oids will be above
FirstBootstrapObjectId. As the oid column now is a normal column the
special bootstrap syntax for oids has been removed.

Oids are not automatically assigned during insertion anymore, all
backend code explicitly assigns oids with GetNewOidWithIndex(). For
the rare case that insertions into the catalog via SQL are called for
the new pg_nextoid() function can be used (which only works on catalog
tables).

The fact that oid columns on system tables are now normal columns
means that they will be included in the set of columns expanded
by * (i.e. SELECT * FROM pg_class will now include the table's oid,
previously it did not). It'd not technically be hard to hide oid
column by default, but that'd mean confusing behavior would either
have to be carried forward forever, or it'd cause breakage down the
line.

While it's not unlikely that further adjustments are needed, the
scope/invasiveness of the patch makes it worthwhile to get merge this
now. It's painful to maintain externally, too complicated to commit
after the code code freeze, and a dependency of a number of other
patches.

Catversion bump, for obvious reasons.

Author: Andres Freund, with contributions by John Naylor
Discussion: https://postgr.es/m/20180930034810.ywp2c7awz7opzcfr@alap3.anarazel.de
2018-11-20 16:00:17 -08:00
Tom Lane 15c7293477 Fix bugs in plpgsql's handling of CALL argument lists.
exec_stmt_call() tried to extract information out of a CALL statement's
argument list without using expand_function_arguments(), apparently in
the hope of saving a few nanoseconds by not processing defaulted
arguments.  It got that quite wrong though, leading to crashes with
named arguments, as well as failure to enforce writability of the
argument for a defaulted INOUT parameter.  Fix and simplify the logic
by using expand_function_arguments() before examining the list.

Also, move the argument-examination to just after producing the CALL
command's plan, before invoking the called procedure.  This ensures
that we'll track possible changes in the procedure's argument list
correctly, and avoids a hazard of the plan cache being flushed while
the procedure executes.

Also fix assorted falsehoods and omissions in associated documentation.

Per bug #15477 from Alexey Stepanov.

Patch by me, with some help from Pavel Stehule.  Back-patch to v11.

Discussion: https://postgr.es/m/15477-86075b1d1d319e0a@postgresql.org
Discussion: https://postgr.es/m/CAFj8pRA6UsujpTs9Sdwmk-R6yQykPx46wgjj+YZ7zxm4onrDyw@mail.gmail.com
2018-11-04 13:25:39 -05:00
Peter Eisentraut 7ceb6fb84c doc: Clarify some wording in PL/pgSQL about transactions
Some text was still claiming that committing transactions was not
possible in PL/pgSQL.
2018-08-22 15:42:22 +02:00
Peter Eisentraut 0a63f996e0 Change PROCEDURE to FUNCTION in CREATE TRIGGER syntax
Since procedures are now a different thing from functions, change the
CREATE TRIGGER and CREATE EVENT TRIGGER syntax to use FUNCTION in the
clause that specifies the function.  PROCEDURE is still accepted for
compatibility.

pg_dump and ruleutils.c output is not changed yet, because that would
require a change in information_schema.sql and thus a catversion change.

Reported-by: Peter Geoghegan <pg@bowt.ie>
Reviewed-by: Jonathan S. Katz <jonathan.katz@excoventures.com>
2018-08-22 14:44:49 +02:00
Peter Eisentraut b19495772e doc: Update uses of the word "procedure"
Historically, the term procedure was used as a synonym for function in
Postgres/PostgreSQL.  Now we have procedures as separate objects from
functions, so we need to clean up the documentation to not mix those
terms.

In particular, mentions of "trigger procedures" are changed to "trigger
functions", and access method "support procedures" are changed to
"support functions".  (The latter already used FUNCTION in the SQL
syntax anyway.)  Also, the terminology in the SPI chapter has been
cleaned up.

A few tests, examples, and code comments are also adjusted to be
consistent with documentation changes, but not everything.

Reported-by: Peter Geoghegan <pg@bowt.ie>
Reviewed-by: Jonathan S. Katz <jonathan.katz@excoventures.com>
2018-08-22 14:44:49 +02:00
Tomas Vondra 167075be3a Add strict_multi_assignment and too_many_rows plpgsql checks
Until now shadowed_variables was the only plpgsql check supported by
plpgsql.extra_warnings and plpgsql.extra_errors.  This patch introduces
two new checks - strict_multi_assignment and too_many_rows.  Unlike
shadowed_variables, these new checks are enforced at run-time.

strict_multi_assignment checks that commands allowing multi-assignment
(for example SELECT INTO) have the same number of sources and targets.
too_many_rows checks that queries with an INTO clause return one row
exactly.

These checks are aimed at cases that are technically valid and allowed,
but are often a sign of a bug.  Therefore those checks are expected to
be enabled primarily in development and testing environments.

Author: Pavel Stehule
Reviewed-by: Stephen Frost, Tomas Vondra
Discussion: https://www.postgresql.org/message-id/flat/CAFj8pRA2kKRDKpUNwLY0GeG1OqOp+tLS2yQA1V41gzuSz-hCng@mail.gmail.com
2018-07-25 01:46:32 +02:00
Tom Lane 632b4ae92d Doc: minor improvement in pl/pgsql FETCH/MOVE documentation.
Explain that you can use any integer expression for the "count" in
pl/pgsql's versions of FETCH/MOVE, unlike the SQL versions which only
allow a constant.

Remove the duplicate version of this para under MOVE.  I don't see
a good reason to maintain two identical paras when we just said that
MOVE works exactly like FETCH.

Per Pavel Stehule, though I didn't use his text.

Discussion: https://postgr.es/m/CAFj8pRAcvSXcNdUGx43bOK1e3NNPbQny7neoTLN42af+8MYWEA@mail.gmail.com
2018-07-12 12:29:03 -04:00
Simon Riggs 08ea7a2291 Revert MERGE patch
This reverts commits d204ef6377,
83454e3c2b and a few more commits thereafter
(complete list at the end) related to MERGE feature.

While the feature was fully functional, with sufficient test coverage and
necessary documentation, it was felt that some parts of the executor and
parse-analyzer can use a different design and it wasn't possible to do that in
the available time. So it was decided to revert the patch for PG11 and retry
again in the future.

Thanks again to all reviewers and bug reporters.

List of commits reverted, in reverse chronological order:

 f1464c5380 Improve parse representation for MERGE
 ddb4158579 MERGE syntax diagram correction
 530e69e59b Allow cpluspluscheck to pass by renaming variable
 01b88b4df5 MERGE minor errata
 3af7b2b0d4 MERGE fix variable warning in non-assert builds
 a5d86181ec MERGE INSERT allows only one VALUES clause
 4b2d44031f MERGE post-commit review
 4923550c20 Tab completion for MERGE
 aa3faa3c7a WITH support in MERGE
 83454e3c2b New files for MERGE
 d204ef6377 MERGE SQL Command following SQL:2016

Author: Pavan Deolasee
Reviewed-by: Michael Paquier
2018-04-12 11:22:56 +01:00
Simon Riggs d204ef6377 MERGE SQL Command following SQL:2016
MERGE performs actions that modify rows in the target table
using a source table or query. MERGE provides a single SQL
statement that can conditionally INSERT/UPDATE/DELETE rows
a task that would other require multiple PL statements.
e.g.

MERGE INTO target AS t
USING source AS s
ON t.tid = s.sid
WHEN MATCHED AND t.balance > s.delta THEN
  UPDATE SET balance = t.balance - s.delta
WHEN MATCHED THEN
  DELETE
WHEN NOT MATCHED AND s.delta > 0 THEN
  INSERT VALUES (s.sid, s.delta)
WHEN NOT MATCHED THEN
  DO NOTHING;

MERGE works with regular and partitioned tables, including
column and row security enforcement, as well as support for
row, statement and transition triggers.

MERGE is optimized for OLTP and is parameterizable, though
also useful for large scale ETL/ELT. MERGE is not intended
to be used in preference to existing single SQL commands
for INSERT, UPDATE or DELETE since there is some overhead.
MERGE can be used statically from PL/pgSQL.

MERGE does not yet support inheritance, write rules,
RETURNING clauses, updatable views or foreign tables.
MERGE follows SQL Standard per the most recent SQL:2016.

Includes full tests and documentation, including full
isolation tests to demonstrate the concurrent behavior.

This version written from scratch in 2017 by Simon Riggs,
using docs and tests originally written in 2009. Later work
from Pavan Deolasee has been both complex and deep, leaving
the lead author credit now in his hands.
Extensive discussion of concurrency from Peter Geoghegan,
with thanks for the time and effort contributed.

Various issues reported via sqlsmith by Andreas Seltenreich

Authors: Pavan Deolasee, Simon Riggs
Reviewer: Peter Geoghegan, Amit Langote, Tomas Vondra, Simon Riggs

Discussion:
https://postgr.es/m/CANP8+jKitBSrB7oTgT9CY2i1ObfOt36z0XMraQc+Xrz8QB0nXA@mail.gmail.com
https://postgr.es/m/CAH2-WzkJdBuxj9PO=2QaO9-3h3xGbQPZ34kJH=HukRekwM-GZg@mail.gmail.com
2018-04-03 09:28:16 +01:00
Simon Riggs 7cf8a5c302 Revert "Modified files for MERGE"
This reverts commit 354f13855e.
2018-04-02 21:34:15 +01:00
Simon Riggs 354f13855e Modified files for MERGE 2018-04-02 21:12:47 +01:00
Peter Eisentraut 056a5a3f63 Allow committing inside cursor loop
Previously, committing or aborting inside a cursor loop was prohibited
because that would close and remove the cursor.  To allow that,
automatically convert such cursors to holdable cursors so they survive
commits or rollbacks.  Portals now have a new state "auto-held", which
means they have been converted automatically from pinned.  An auto-held
portal is kept on transaction commit or rollback, but is still removed
when returning to the main loop on error.

This supports all languages that have cursor loop constructs: PL/pgSQL,
PL/Python, PL/Perl.

Reviewed-by: Ildus Kurbangaliev <i.kurbangaliev@postgrespro.ru>
2018-03-28 19:03:26 -04:00
Peter Eisentraut d92bc83c48 PL/pgSQL: Nested CALL with transactions
So far, a nested CALL or DO in PL/pgSQL would not establish a context
where transaction control statements were allowed.  This fixes that by
handling CALL and DO specially in PL/pgSQL, passing the atomic/nonatomic
execution context through and doing the required management around
transaction boundaries.

Reviewed-by: Tomas Vondra <tomas.vondra@2ndquadrant.com>
2018-03-28 13:31:27 -04:00
Tom Lane b6cbe9ea1a Doc: typo fix, "PG_" should be "TG_" here.
Too much PG on the brain in commit 769159fd3, evidently.
Noted by marcelhuberfoo@gmail.com.

Discussion: https://postgr.es/m/152154834496.11957.17112112802418832865@wrigleys.postgresql.org
2018-03-20 11:34:25 -04:00
Peter Eisentraut 33803f67f1 Support INOUT arguments in procedures
In a top-level CALL, the values of INOUT arguments will be returned as a
result row.  In PL/pgSQL, the values are assigned back to the input
arguments.  In other languages, the same convention as for return a
record from a function is used.  That does not require any code changes
in the PL implementations.

Reviewed-by: Pavel Stehule <pavel.stehule@gmail.com>
2018-03-14 12:07:28 -04:00
Tom Lane 4b93f57999 Make plpgsql use its DTYPE_REC code paths for composite-type variables.
Formerly, DTYPE_REC was used only for variables declared as "record";
variables of named composite types used DTYPE_ROW, which is faster for
some purposes but much less flexible.  In particular, the ROW code paths
are entirely incapable of dealing with DDL-caused changes to the number
or data types of the columns of a row variable, once a particular plpgsql
function has been parsed for the first time in a session.  And, since the
stored representation of a ROW isn't a tuple, there wasn't any easy way
to deal with variables of domain-over-composite types, since the domain
constraint checking code would expect the value to be checked to be a
tuple.  A lesser, but still real, annoyance is that ROW format cannot
represent a true NULL composite value, only a row of per-field NULL
values, which is not exactly the same thing.

Hence, switch to using DTYPE_REC for all composite-typed variables,
whether "record", named composite type, or domain over named composite
type.  DTYPE_ROW remains but is used only for its native purpose, to
represent a fixed-at-compile-time list of variables, for instance the
targets of an INTO clause.

To accomplish this without taking significant performance losses, introduce
infrastructure that allows storing composite-type variables as "expanded
objects", similar to the "expanded array" infrastructure introduced in
commit 1dc5ebc90.  A composite variable's value is thereby kept (most of
the time) in the form of separate Datums, so that field accesses and
updates are not much more expensive than they were in the ROW format.
This holds the line, more or less, on performance of variables of named
composite types in field-access-intensive microbenchmarks, and makes
variables declared "record" perform much better than before in similar
tests.  In addition, the logic involved with enforcing composite-domain
constraints against updates of individual fields is in the expanded
record infrastructure not plpgsql proper, so that it might be reusable
for other purposes.

In further support of this, introduce a typcache feature for assigning a
unique-within-process identifier to each distinct tuple descriptor of
interest; in particular, DDL alterations on composite types result in a new
identifier for that type.  This allows very cheap detection of the need to
refresh tupdesc-dependent data.  This improves on the "tupDescSeqNo" idea
I had in commit 687f096ea: that assigned identifying sequence numbers to
successive versions of individual composite types, but the numbers were not
unique across different types, nor was there support for assigning numbers
to registered record types.

In passing, allow plpgsql functions to accept as well as return type
"record".  There was no good reason for the old restriction, and it
was out of step with most of the other PLs.

Tom Lane, reviewed by Pavel Stehule

Discussion: https://postgr.es/m/8962.1514399547@sss.pgh.pa.us
2018-02-13 18:52:21 -05:00
Peter Eisentraut 8561e4840c Transaction control in PL procedures
In each of the supplied procedural languages (PL/pgSQL, PL/Perl,
PL/Python, PL/Tcl), add language-specific commit and rollback
functions/commands to control transactions in procedures in that
language.  Add similar underlying functions to SPI.  Some additional
cleanup so that transaction commit or abort doesn't blow away data
structures still used by the procedure call.  Add execution context
tracking to CALL and DO statements so that transaction control commands
can only be issued in top-level procedure and block calls, not function
calls or other procedure or block calls.

- SPI

Add a new function SPI_connect_ext() that is like SPI_connect() but
allows passing option flags.  The only option flag right now is
SPI_OPT_NONATOMIC.  A nonatomic SPI connection can execute transaction
control commands, otherwise it's not allowed.  This is meant to be
passed down from CALL and DO statements which themselves know in which
context they are called.  A nonatomic SPI connection uses different
memory management.  A normal SPI connection allocates its memory in
TopTransactionContext.  For nonatomic connections we use PortalContext
instead.  As the comment in SPI_connect_ext() (previously SPI_connect())
indicates, one could potentially use PortalContext in all cases, but it
seems safest to leave the existing uses alone, because this stuff is
complicated enough already.

SPI also gets new functions SPI_start_transaction(), SPI_commit(), and
SPI_rollback(), which can be used by PLs to implement their transaction
control logic.

- portalmem.c

Some adjustments were made in the code that cleans up portals at
transaction abort.  The portal code could already handle a command
*committing* a transaction and continuing (e.g., VACUUM), but it was not
quite prepared for a command *aborting* a transaction and continuing.

In AtAbort_Portals(), remove the code that marks an active portal as
failed.  As the comment there already predicted, this doesn't work if
the running command wants to keep running after transaction abort.  And
it's actually not necessary, because pquery.c is careful to run all
portal code in a PG_TRY block and explicitly runs MarkPortalFailed() if
there is an exception.  So the code in AtAbort_Portals() is never used
anyway.

In AtAbort_Portals() and AtCleanup_Portals(), we need to be careful not
to clean up active portals too much.  This mirrors similar code in
PreCommit_Portals().

- PL/Perl

Gets new functions spi_commit() and spi_rollback()

- PL/pgSQL

Gets new commands COMMIT and ROLLBACK.

Update the PL/SQL porting example in the documentation to reflect that
transactions are now possible in procedures.

- PL/Python

Gets new functions plpy.commit and plpy.rollback.

- PL/Tcl

Gets new commands commit and rollback.

Reviewed-by: Andrew Dunstan <andrew.dunstan@2ndquadrant.com>
2018-01-22 08:43:06 -05:00
Tom Lane 3c1e9fd232 Fix sample INSTR() functions in the plpgsql documentation.
These functions are stated to be Oracle-compatible, but they weren't.
Yugo Nagata noticed that while our code returns zero for a zero or
negative fourth parameter (occur_index), Oracle throws an error.
Further testing by me showed that there was also a discrepancy in the
interpretation of a negative third parameter (beg_index): Oracle thinks
that a negative beg_index indicates the last place where the target
substring can *begin*, whereas our code thinks it is the last place
where the target can *end*.

Adjust the sample code to behave like Oracle in both these respects.
Also change it to be a CDATA[] section, simplifying copying-and-pasting
out of the documentation source file.  And fix minor problems in the
introductory comment, which wasn't very complete or accurate.

Back-patch to all supported branches.  Although this patch only touches
documentation, we should probably call it out as a bug fix in the next
minor release notes, since users who have adopted the functions will
likely want to update their versions.

Yugo Nagata and Tom Lane

Discussion: https://postgr.es/m/20171229191705.c0b43a8c.nagata@sraoss.co.jp
2018-01-10 17:13:47 -05:00
Peter Eisentraut e4128ee767 SQL procedures
This adds a new object type "procedure" that is similar to a function
but does not have a return type and is invoked by the new CALL statement
instead of SELECT or similar.  This implementation is aligned with the
SQL standard and compatible with or similar to other SQL implementations.

This commit adds new commands CALL, CREATE/ALTER/DROP PROCEDURE, as well
as ALTER/DROP ROUTINE that can refer to either a function or a
procedure (or an aggregate function, as an extension to SQL).  There is
also support for procedures in various utility commands such as COMMENT
and GRANT, as well as support in pg_dump and psql.  Support for defining
procedures is available in all the languages supplied by the core
distribution.

While this commit is mainly syntax sugar around existing functionality,
future features will rely on having procedures as a separate object
type.

Reviewed-by: Andrew Dunstan <andrew.dunstan@2ndquadrant.com>
2017-11-30 11:03:20 -05:00
Peter Eisentraut 3c49c6facb Convert documentation to DocBook XML
Since some preparation work had already been done, the only source
changes left were changing empty-element tags like <xref linkend="foo">
to <xref linkend="foo"/>, and changing the DOCTYPE.

The source files are still named *.sgml, but they are actually XML files
now.  Renaming could be considered later.

In the build system, the intermediate step to convert from SGML to XML
is removed.  Everything is build straight from the source files again.
The OpenSP (or the old SP) package is no longer needed.

The documentation toolchain instructions are updated and are much
simpler now.

Peter Eisentraut, Alexander Lakhin, Jürgen Purtz
2017-11-23 09:44:28 -05:00
Peter Eisentraut c29c578908 Don't use SGML empty tags
For DocBook XML compatibility, don't use SGML empty tags (</>) anymore,
replace by the full tag name.  Add a warning option to catch future
occurrences.

Alexander Lakhin, Jürgen Purtz
2017-10-17 15:10:33 -04:00
Tom Lane 936df5ba80 Doc: add example of transition table use in a trigger.
I noticed that there were exactly no complete examples of use of
a transition table in a trigger function, and no clear description
of just how you'd do it either.  Improve that.
2017-09-16 15:31:26 -04:00
Peter Eisentraut 1c53f612bc Escape < and & in SGML
This is not required in SGML, but will be in XML, so this is a step to
prepare for the conversion to XML.  (It is still not required to escape
>, but we did it here in some cases for symmetry.)

Add a command-line option to osx/onsgmls calls to warn about unescaped
occurrences in the future.

Author: Alexander Law <exclusion@gmail.com>
Author: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
2017-09-06 11:22:43 -04:00
Tom Lane 533463307b Doc: explain dollar quoting in the intro part of the pl/pgsql chapter.
We're throwing people into the guts of the syntax with not much context;
let's back up one step and point out that this goes inside a literal in
a CREATE FUNCTION command.  Per suggestion from Kurt Kartaltepe.

Discussion: https://postgr.es/m/CACawnnyWAmH+au8nfZhLiFfWKjXy4d0kY+eZWfcxPRnjVfaa_Q@mail.gmail.com
2017-07-17 16:43:06 -04:00
Robert Haas 8e709a612f doc: Remove unnecessary RETURN statements from example.
Paul Jungwirth, reviewed by Ashutosh Bapat.

Discussion: http://postgr.es/m/e24a6a6d-5670-739b-00f3-41a226a80f25@illuminatedcomputing.com
2017-05-16 11:36:47 -04:00
Peter Eisentraut afd79873a0 Capitalize names of PLs consistently
Author: Daniel Gustafsson <daniel@yesql.se>
2017-04-05 00:38:25 -04:00
Peter Eisentraut 47b55d4174 doc: Put callouts in SQL comments
This makes copy-and-pasting the SQL code easier.

From: Thomas Munro <thomas.munro@enterprisedb.com>
2017-03-03 15:03:03 -05:00
Tom Lane ade64d05a0 Doc: improve discussion of plpgsql's GET DIAGNOSTICS, other minor fixes.
9.4 added a second description of GET DIAGNOSTICS that was totally
independent of the existing one, resulting in each description lying to the
extent that it claimed the set of status items it described was complete.
Fix that, and do some minor markup improvement.

Also some other small fixes per bug #14258 from Dilian Palauzov.

Discussion: <20160718181437.1414.40802@wrigleys.postgresql.org>
2016-07-18 16:52:06 -04:00
Tom Lane 769159fd39 Docs: minor improvements for documentation about plpgsql triggers.
Fabien Coelho, some further wordsmithing by me
2016-07-08 13:23:09 -04:00
Tom Lane 23f11dc21b In examples of Oracle PL/SQL code, use varchar2 not varchar.
Oracle recommends using VARCHAR2 not VARCHAR, allegedly because they might
someday change VARCHAR to be spec-compliant about distinguishing null from
empty string.  (I'm not holding my breath, though.)  Our examples of PL/SQL
code were using VARCHAR, which while not wrong is missing the pedagogical
opportunity to talk about converting Oracle type names to Postgres.  So
switch the examples to use VARCHAR2, and add some text about what to do
with common Oracle type names like VARCHAR2 and NUMBER.  (There is probably
more to be said here, but those are the ones I'm sure about offhand.)
Per suggestion from rapg12@gmail.com.

Discussion: <20160521140046.22591.24672@wrigleys.postgresql.org>
2016-05-24 13:30:40 -04:00
Peter Eisentraut 122b99478a doc: Small wording change for clarity
From: Martín Marqués <martin@2ndquadrant.com>
2016-05-12 08:32:12 -04:00
Peter Eisentraut 741ccd5015 Use gender-neutral language in documentation
Based on patch by Thomas Munro <thomas.munro@enterprisedb.com>, although
I rephrased most of the initial work.
2015-09-21 22:57:29 -04:00