Received: from malur.postgresql.org ([217.196.149.56])
	by arkaria.postgresql.org with esmtps
 (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256)
	(Exim 4.92)
	(envelope-from <pgsql-docs-owner+archive@lists.postgresql.org>)
	id 1kAeE8-0001ro-2q
	for pgsql-docs@arkaria.postgresql.org; Tue, 25 Aug 2020 19:03:24 +0000
Received: from localhost ([127.0.0.1] helo=malur.postgresql.org)
	by malur.postgresql.org with esmtp (Exim 4.92)
	(envelope-from <pgsql-docs-owner+archive@lists.postgresql.org>)
	id 1kAeE6-0000wi-VW
	for pgsql-docs@arkaria.postgresql.org; Tue, 25 Aug 2020 19:03:22 +0000
Received: from makus.postgresql.org ([2001:4800:3e1:1::229])
	by malur.postgresql.org with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256)
	(Exim 4.92)
	(envelope-from <bruce@momjian.us>)
	id 1kAeE6-0000wb-PI
	for pgsql-docs@lists.postgresql.org; Tue, 25 Aug 2020 19:03:22 +0000
Received: from momjian.us ([72.94.173.45])
	by makus.postgresql.org with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256)
	(Exim 4.92)
	(envelope-from <bruce@momjian.us>)
	id 1kAeE0-0007iF-CE
	for pgsql-docs@lists.postgresql.org; Tue, 25 Aug 2020 19:03:21 +0000
Received: from bruce by momjian.us with local (Exim 4.92)
	(envelope-from <bruce@momjian.us>)
	id 1kAeDx-0003FP-Sb; Tue, 25 Aug 2020 15:03:13 -0400
Date: Tue, 25 Aug 2020 15:03:13 -0400
From: Bruce Momjian <bruce@momjian.us>
To: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
Cc: Pavel Stehule <pavel.stehule@gmail.com>,
	"David G. Johnston" <david.g.johnston@gmail.com>,
	Robin Abbi <robin.abbi@downley.net>,
	Dave Cramer <davecramer@postgres.rocks>,
	Pg Docs <pgsql-docs@lists.postgresql.org>
Subject: Re: Procedures
Message-ID: <20200825190313.GE26852@momjian.us>
References: 
 <CAKFQuwaEnUAaF=rPhsLymWDsGg71CXAswVRNnhxV+h=3q+3pDg@mail.gmail.com>
 <20200822171447.GF26781@momjian.us>
 <CAKFQuwbbfW01BGT=X6buQySXMr08P98yhG-cja22_rPfravE2g@mail.gmail.com>
 <20200824150056.GI26781@momjian.us>
 <CAFj8pRAMRsC8r0bBsqRz_hiVH+TxOrTa0_0F+c5qBwbNis7=uQ@mail.gmail.com>
 <20200824153557.GK26781@momjian.us>
 <20200824153847.GL26781@momjian.us>
 <CAFj8pRCZOa6739u88_vMV5uqB2kWFST3DCU0Y6wPx1b9DFfbUg@mail.gmail.com>
 <20200824160023.GM26781@momjian.us>
 <bdf3066b-8779-b76e-ea49-5866dbf6cbcb@2ndquadrant.com>
MIME-Version: 1.0
Content-Type: multipart/mixed; boundary="vGgW1X5XWziG23Ko"
Content-Disposition: inline
In-Reply-To: <bdf3066b-8779-b76e-ea49-5866dbf6cbcb@2ndquadrant.com>
User-Agent: Mutt/1.10.1 (2018-07-13)
List-Id: <pgsql-docs.lists.postgresql.org>
List-Help: <https://lists.postgresql.org/manage/>
List-Subscribe: <https://lists.postgresql.org/manage/>
List-Post: <mailto:pgsql-docs@lists.postgresql.org>
List-Owner: <mailto:pgsql-docs-owner@lists.postgresql.org>
List-Archive: <https://www.postgresql.org/list/pgsql-docs>
Precedence: bulk


--vGgW1X5XWziG23Ko
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline

On Tue, Aug 25, 2020 at 08:38:11PM +0200, Peter Eisentraut wrote:
> On 2020-08-24 18:00, Bruce Momjian wrote:
> > -    command, a procedure is called explicitly using
> > -    the <xref linkend="sql-call"/> statement.
> > +    command, a procedure is called in isolation using
> > +    the <xref linkend="sql-call"/> command.  If the CALL command is not
> > +    part of an explicit transaction, a procedure can commit, rollback,
> > +    and begin new transactions during its execution, which is not possible
> > +    in functions.
> 
> There are additional conditions for when a procedure can do transaction
> control, and it also depends on the language.  It's not clear how much
> detail we should give in a general section like this.  Often people read
> this and then wonder why it doesn't work.

I have updated the patch to mention it is dependend on the server-side
language.

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EnterpriseDB                             https://enterprisedb.com

  The usefulness of a cup is in its emptiness, Bruce Lee


--vGgW1X5XWziG23Ko
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment; filename="proc.diff"

diff --git a/doc/src/sgml/xfunc.sgml b/doc/src/sgml/xfunc.sgml
index 6de464c654..732d935521 100644
--- a/doc/src/sgml/xfunc.sgml
+++ b/doc/src/sgml/xfunc.sgml
@@ -84,8 +84,11 @@
     A procedure is a database object similar to a function.  The difference is
     that a procedure does not return a value, so there is no return type
     declaration.  While a function is called as part of a query or DML
-    command, a procedure is called explicitly using
-    the <xref linkend="sql-call"/> statement.
+    command, a procedure is called in isolation using
+    the <xref linkend="sql-call"/> command.  If the CALL command is not
+    part of an explicit transaction, a procedure in many server-side
+    languages can commit, rollback, and begin new transactions during
+    its execution, which is not possible in functions.
    </para>
 
    <para>

--vGgW1X5XWziG23Ko--