Re: [HACKERS] Transaction control in procedures

Peter Eisentraut Wed, 06 Dec 2017 06:42:41 -0800

On 12/5/17 13:33, Robert Haas wrote:
> On Tue, Dec 5, 2017 at 1:25 PM, Peter Eisentraut
> <peter.eisentr...@2ndquadrant.com> wrote:
>> I think ROLLBACK in a cursor loop might not make sense, because the
>> cursor query itself could have side effects, so a rollback would have to
>> roll back the entire loop.  That might need more refined analysis before
>> it could be allowed.
> 
> COMMIT really has the same problem; if the cursor query has side
> effects, you can't commit those side effects piecemeal as the loop
> executed and have things behave sanely.


The first COMMIT inside the loop would commit the cursor query.  This
isn't all that different from what you'd get now if you coded this
manually using holdable cursors or just plain client code.  Clearly, you
can create a mess if the loop body interacts with the loop expression,
but that's already the case.

But if you coded something like this yourself now and ran a ROLLBACK
inside the loop, the holdable cursor would disappear (unless previously
committed), so you couldn't proceed with the loop.

The SQL standard for persistent stored modules explicitly prohibits
COMMIT and ROLLBACK in cursor loop bodies.  But I think people will
eventually want it.

>>> - COMMIT or ROLLBACK inside a procedure with a SET clause attached,
>>
>> That also needs to be prohibited because of the way the GUC nesting
>> currently works.  It's probably possible to fix it, but it would be a
>> separate effort.
>>
>>> and/or while SET LOCAL is in effect either at the inner or outer
>>> level.
>>
>> That seems to work fine.
> 
> These two are related -- if you don't permit anything that makes
> temporary changes to GUCs at all, like SET clauses attached to
> functions, then SET LOCAL won't cause any problems.  The problem is if
> you do a transaction operation when something set locally is in the
> stack of values, but not at the top.

Yes, that's exactly the problem.  So right now I'm just preventing the
problematic scenario.  So fix that, one would possibly have to replace
the stack by something not quite a stack.


New patch attached.

-- 
Peter Eisentraut              http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

From 18aaf292fbb22647e09c38cc21b56ff98643e518 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <pete...@gmx.net>
Date: Wed, 6 Dec 2017 09:29:25 -0500
Subject: [PATCH v4] 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.
---
 doc/src/sgml/plperl.sgml                          |  49 +++++
 doc/src/sgml/plpgsql.sgml                         |  91 ++++----
 doc/src/sgml/plpython.sgml                        |  38 ++++
 doc/src/sgml/pltcl.sgml                           |  41 ++++
 doc/src/sgml/ref/call.sgml                        |   7 +
 doc/src/sgml/ref/create_procedure.sgml            |   7 +
 doc/src/sgml/ref/do.sgml                          |   7 +
 doc/src/sgml/spi.sgml                             | 219 ++++++++++++++++++++
 src/backend/commands/functioncmds.c               |  45 +++-
 src/backend/executor/spi.c                        | 112 ++++++++--
 src/backend/tcop/utility.c                        |   6 +-
 src/backend/utils/mmgr/portalmem.c                |  58 +++---
 src/include/commands/defrem.h                     |   4 +-
 src/include/executor/spi.h                        |   5 +
 src/include/executor/spi_priv.h                   |   4 +
 src/include/nodes/nodes.h                         |   3 +-
 src/include/nodes/parsenodes.h                    |   7 +
 src/include/utils/portal.h                        |   1 +
 src/pl/plperl/GNUmakefile                         |   2 +-
 src/pl/plperl/SPI.xs                              |  12 ++
 src/pl/plperl/expected/plperl_transaction.out     |  94 +++++++++
 src/pl/plperl/plperl.c                            |   6 +
 src/pl/plperl/sql/plperl_transaction.sql          |  88 ++++++++
 src/pl/plpgsql/src/pl_exec.c                      |  66 +++++-
 src/pl/plpgsql/src/pl_funcs.c                     |  44 ++++
 src/pl/plpgsql/src/pl_gram.y                      |  34 +++
 src/pl/plpgsql/src/pl_handler.c                   |   8 +
 src/pl/plpgsql/src/pl_scanner.c                   |   2 +
 src/pl/plpgsql/src/plpgsql.h                      |  22 +-
 src/pl/plpython/Makefile                          |   1 +
 src/pl/plpython/expected/plpython_test.out        |   4 +-
 src/pl/plpython/expected/plpython_transaction.out | 104 ++++++++++
 src/pl/plpython/plpy_main.c                       |   7 +-
 src/pl/plpython/plpy_plpymodule.c                 |  28 +++
 src/pl/plpython/sql/plpython_transaction.sql      |  87 ++++++++
 src/pl/tcl/Makefile                               |   2 +-
 src/pl/tcl/expected/pltcl_transaction.out         |  63 ++++++
 src/pl/tcl/pltcl.c                                |  44 ++++
 src/pl/tcl/sql/pltcl_transaction.sql              |  60 ++++++
 src/test/regress/expected/plpgsql.out             | 241 ++++++++++++++++++++++
 src/test/regress/sql/plpgsql.sql                  | 214 +++++++++++++++++++
 41 files changed, 1835 insertions(+), 102 deletions(-)
 create mode 100644 src/pl/plperl/expected/plperl_transaction.out
 create mode 100644 src/pl/plperl/sql/plperl_transaction.sql
 create mode 100644 src/pl/plpython/expected/plpython_transaction.out
 create mode 100644 src/pl/plpython/sql/plpython_transaction.sql
 create mode 100644 src/pl/tcl/expected/pltcl_transaction.out
 create mode 100644 src/pl/tcl/sql/pltcl_transaction.sql

diff --git a/doc/src/sgml/plperl.sgml b/doc/src/sgml/plperl.sgml
index 100162dead..82ddf26606 100644
--- a/doc/src/sgml/plperl.sgml
+++ b/doc/src/sgml/plperl.sgml
@@ -661,6 +661,55 @@ <title>Database Access from PL/Perl</title>
     </para>
     </listitem>
     </varlistentry>
+
+    <varlistentry>
+     <term>
+      <literal><function>spi_commit()</function></literal>
+      <indexterm>
+       <primary>spi_commit</primary>
+       <secondary>in PL/Perl</secondary>
+     </indexterm>
+     </term>
+     <term>
+      <literal><function>spi_rollback()</function></literal>
+      <indexterm>
+       <primary>spi_rollback</primary>
+       <secondary>in PL/Perl</secondary>
+      </indexterm>
+     </term>
+     <listitem>
+      <para>
+       Commit or roll back the current transaction.  This can only be called
+       in a procedure or anonymous code block called from the top level.
+       (Note that it is not possible to run the SQL
+       commands <command>COMMIT</command> or <command>ROLLBACK</command>
+       via <function>spi_exec_query</function> or similar.  It has to be done
+       using these functions.)  After a transaction is ended, a new
+       transaction is automatically started, so there is no separate function
+       for that.
+      </para>
+
+      <para>
+       Here is an example:
+<programlisting>
+CREATE PROCEDURE transaction_test1()
+LANGUAGE plperl
+AS $$
+foreach my $i (0..9) {
+    spi_exec_query("INSERT INTO test1 (a) VALUES ($i)");
+    if ($i % 2 == 0) {
+        spi_commit();
+    } else {
+        spi_rollback();
+    }
+}
+$$;
+
+CALL transaction_test1();
+</programlisting>
+      </para>
+     </listitem>
+    </varlistentry>
    </variablelist>
  </sect2>
 
diff --git a/doc/src/sgml/plpgsql.sgml b/doc/src/sgml/plpgsql.sgml
index 7d23ed437e..285467343a 100644
--- a/doc/src/sgml/plpgsql.sgml
+++ b/doc/src/sgml/plpgsql.sgml
@@ -3449,6 +3449,48 @@ <title>Looping Through a Cursor's Result</title>
 
   </sect1>
 
+  <sect1 id="plpgsql-transactions">
+   <title>Transaction Management</title>
+
+   <para>
+    In procedures invoked by the <command>CALL</command> command from the top
+    level as well as in anonymous code blocks called from the top level, it is
+    possible to end transactions using the commands <command>COMMIT</command>
+    and <command>ROLLBACK</command>.  A new transaction is started
+    automatically after a transaction is ended using these commands, so there
+    is no separate <command>START TRANSACTION</command> command.  (And of
+    course, <command>BEGIN</command> and <command>END</command> have different
+    meanings in PL/pgSQL.)
+   </para>
+
+   <para>
+    Here is a simple example:
+<programlisting>
+CREATE PROCEDURE transaction_test1()
+LANGUAGE plpgsql
+AS $$
+BEGIN
+    FOR i IN 0..9 LOOP
+        INSERT INTO test1 (a) VALUES (i);
+        IF i % 2 = 0 THEN
+            COMMIT;
+        ELSE
+            ROLLBACK;
+        END IF;
+    END LOOP;
+END
+$$;
+
+CALL transaction_test1();
+</programlisting>
+   </para>
+
+   <para>
+    Transactions cannot be ended inside loops through query results or inside
+    blocks with exception handlers.
+   </para>
+  </sect1>
+
   <sect1 id="plpgsql-errors-and-messages">
    <title>Errors and Messages</title>
 
@@ -5432,14 +5474,13 @@ <title>Porting a Procedure from 
<application>PL/SQL</application> to <applicatio
 <programlisting>
 CREATE OR REPLACE PROCEDURE cs_create_job(v_job_id IN INTEGER) IS
     a_running_job_count INTEGER;
-    PRAGMA AUTONOMOUS_TRANSACTION; -- <co id="co.plpgsql-porting-pragma"/>
 BEGIN
-    LOCK TABLE cs_jobs IN EXCLUSIVE MODE; -- <co 
id="co.plpgsql-porting-locktable"/>
+    LOCK TABLE cs_jobs IN EXCLUSIVE MODE;
 
     SELECT count(*) INTO a_running_job_count FROM cs_jobs WHERE end_stamp IS 
NULL;
 
     IF a_running_job_count &gt; 0 THEN
-        COMMIT; -- free lock <co id="co.plpgsql-porting-commit"/>
+        COMMIT; -- free lock
         raise_application_error(-20000,
                  'Unable to create a new job: a job is currently running.');
     END IF;
@@ -5459,45 +5500,11 @@ <title>Porting a Procedure from 
<application>PL/SQL</application> to <applicatio
 </programlisting>
    </para>
 
-   <para>
-    Procedures like this can easily be converted into 
<productname>PostgreSQL</productname>
-    functions returning <type>void</type>. This procedure in
-    particular is interesting because it can teach us some things:
-
-    <calloutlist>
-     <callout arearefs="co.plpgsql-porting-pragma">
-      <para>
-       There is no <literal>PRAGMA</literal> statement in 
<productname>PostgreSQL</productname>.
-      </para>
-     </callout>
-
-     <callout arearefs="co.plpgsql-porting-locktable">
-      <para>
-       If you do a <command>LOCK TABLE</command> in 
<application>PL/pgSQL</application>,
-       the lock will not be released until the calling transaction is
-       finished.
-      </para>
-     </callout>
-
-     <callout arearefs="co.plpgsql-porting-commit">
-      <para>
-       You cannot issue <command>COMMIT</command> in a
-       <application>PL/pgSQL</application> function.  The function is
-       running within some outer transaction and so <command>COMMIT</command>
-       would imply terminating the function's execution.  However, in
-       this particular case it is not necessary anyway, because the lock
-       obtained by the <command>LOCK TABLE</command> will be released when
-       we raise an error.
-      </para>
-     </callout>
-    </calloutlist>
-   </para>
-
    <para>
     This is how we could port this procedure to 
<application>PL/pgSQL</application>:
 
 <programlisting>
-CREATE OR REPLACE FUNCTION cs_create_job(v_job_id integer) RETURNS void AS $$
+CREATE OR REPLACE PROCEDURE cs_create_job(v_job_id integer) AS $$
 DECLARE
     a_running_job_count integer;
 BEGIN
@@ -5506,6 +5513,7 @@ <title>Porting a Procedure from 
<application>PL/SQL</application> to <applicatio
     SELECT count(*) INTO a_running_job_count FROM cs_jobs WHERE end_stamp IS 
NULL;
 
     IF a_running_job_count &gt; 0 THEN
+        COMMIT; -- free lock
         RAISE EXCEPTION 'Unable to create a new job: a job is currently 
running'; -- <co id="co.plpgsql-porting-raise"/>
     END IF;
 
@@ -5518,6 +5526,7 @@ <title>Porting a Procedure from 
<application>PL/SQL</application> to <applicatio
         WHEN unique_violation THEN -- <co id="co.plpgsql-porting-exception"/>
             -- don't worry if it already exists
     END;
+    COMMIT;
 END;
 $$ LANGUAGE plpgsql;
 </programlisting>
@@ -5541,12 +5550,6 @@ <title>Porting a Procedure from 
<application>PL/SQL</application> to <applicatio
       </para>
      </callout>
     </calloutlist>
-
-    The main functional difference between this procedure and the
-    Oracle equivalent is that the exclusive lock on the 
<literal>cs_jobs</literal>
-    table will be held until the calling transaction completes.  Also, if
-    the caller later aborts (for example due to an error), the effects of
-    this procedure will be rolled back.
    </para>
    </example>
   </sect2>
diff --git a/doc/src/sgml/plpython.sgml b/doc/src/sgml/plpython.sgml
index 0dbeee1fa2..76cc0fc314 100644
--- a/doc/src/sgml/plpython.sgml
+++ b/doc/src/sgml/plpython.sgml
@@ -1370,6 +1370,44 @@ <title>Older Python Versions</title>
   </sect2>
  </sect1>
 
+ <sect1 id="plpython-transactions">
+  <title>Transaction Management</title>
+
+  <para>
+   In a procedure called from the top level or an anonymous code block called
+   from the top level it is possible to control transactions.  To commit the
+   current transaction, call <literal>plpy.commit()</literal>.  To roll back
+   the current transaction, call <literal>plpy.rollback()</literal>.  (Note
+   that it is not possible to run the SQL commands <command>COMMIT</command>
+   or <command>ROLLBACK</command> via <function>plpy.execute</function> or
+   similar.  It has to be done using these functions.)  After a transaction is
+   ended, a new transaction is automatically started, so there is no separate
+   function for that.
+  </para>
+
+  <para>
+   Here is an example:
+<programlisting>
+CREATE PROCEDURE transaction_test1()
+LANGUAGE plpythonu
+AS $$
+for i in range(0, 10):
+    plpy.execute("INSERT INTO test1 (a) VALUES (%d)" % i)
+    if i % 2 == 0:
+        plpy.commit()
+    else:
+        plpy.rollback()
+$$;
+
+CALL transaction_test1();
+</programlisting>
+  </para>
+
+  <para>
+   Transactions cannot be ended when an explicit subtransaction is active.
+  </para>
+ </sect1>
+
  <sect1 id="plpython-util">
   <title>Utility Functions</title>
   <para>
diff --git a/doc/src/sgml/pltcl.sgml b/doc/src/sgml/pltcl.sgml
index 8018783b0a..f7604d4787 100644
--- a/doc/src/sgml/pltcl.sgml
+++ b/doc/src/sgml/pltcl.sgml
@@ -1002,6 +1002,47 @@ <title>Explicit Subtransactions in PL/Tcl</title>
     </para>
    </sect1>
 
+   <sect1 id="pltcl-transactions">
+    <title>Transaction Management</title>
+
+    <para>
+     In a procedure called from the top level or an anonymous code block
+     called from the top level it is possible to control transactions.  To
+     commit the current transaction, call the <literal>commit</literal>
+     command.  To roll back the current transaction, call
+     the <literal>rollback</literal> command.  (Note that it is not possible
+     to run the SQL commands <command>COMMIT</command>
+     or <command>ROLLBACK</command> via <function>spi_exec</function> or
+     similar.  It has to be done using these functions.)  After a transaction
+     is ended, a new transaction is automatically started, so there is no
+     separate command for that.
+    </para>
+
+    <para>
+     Here is an example:
+<programlisting>
+CREATE PROCEDURE transaction_test1()
+LANGUAGE pltcl
+AS $$
+for {set i 0} {$i &lt; 10} {incr i} {
+    spi_exec "INSERT INTO test1 (a) VALUES ($i)"
+    if {$i % 2 == 0} {
+        commit
+    } else {
+        rollback
+    }
+}
+$$;
+
+CALL transaction_test1();
+</programlisting>
+    </para>
+
+    <para>
+     Transactions cannot be ended when an explicit subtransaction is active.
+    </para>
+   </sect1>
+
    <sect1 id="pltcl-config">
     <title>PL/Tcl Configuration</title>
 
diff --git a/doc/src/sgml/ref/call.sgml b/doc/src/sgml/ref/call.sgml
index 2741d8d15e..03da4518ee 100644
--- a/doc/src/sgml/ref/call.sgml
+++ b/doc/src/sgml/ref/call.sgml
@@ -70,6 +70,13 @@ <title>Notes</title>
   <para>
    To call a function (not a procedure), use <command>SELECT</command> instead.
   </para>
+
+  <para>
+   If <command>CALL</command> is executed in a transaction block, then the
+   called procedure cannot execute transaction control statements.
+   Transaction control statements are only allowed if <command>CALL</command>
+   is executed in its own transaction.
+  </para>
  </refsect1>
 
  <refsect1>
diff --git a/doc/src/sgml/ref/create_procedure.sgml 
b/doc/src/sgml/ref/create_procedure.sgml
index d712043824..bbf8b03d04 100644
--- a/doc/src/sgml/ref/create_procedure.sgml
+++ b/doc/src/sgml/ref/create_procedure.sgml
@@ -228,6 +228,13 @@ <title>Parameters</title>
        procedure exit, unless the current transaction is rolled back.
       </para>
 
+      <para>
+       If a <literal>SET</literal> clause is attached to a procedure, then
+       that procedure cannot execute transaction control statements (for
+       example, <command>COMMIT</command> and <command>ROLLBACK</command>,
+       depending on the language).
+      </para>
+
       <para>
        See <xref linkend="sql-set"/> and
        <xref linkend="runtime-config"/>
diff --git a/doc/src/sgml/ref/do.sgml b/doc/src/sgml/ref/do.sgml
index 061218b135..b9a6f9a6fd 100644
--- a/doc/src/sgml/ref/do.sgml
+++ b/doc/src/sgml/ref/do.sgml
@@ -91,6 +91,13 @@ <title>Notes</title>
    This is the same privilege requirement as for creating a function
    in the language.
   </para>
+
+  <para>
+   If <command>DO</command> is executed in a transaction block, then the
+   procedure code cannot execute transaction control statements.  Transaction
+   control statements are only allowed if <command>DO</command> is executed in
+   its own transaction.
+  </para>
  </refsect1>
 
  <refsect1 id="sql-do-examples">
diff --git a/doc/src/sgml/spi.sgml b/doc/src/sgml/spi.sgml
index 350f0863e9..6df8f8368b 100644
--- a/doc/src/sgml/spi.sgml
+++ b/doc/src/sgml/spi.sgml
@@ -4325,6 +4325,225 @@ <title>Return Value</title>
 
  </sect1>
 
+ <sect1 id="spi-transaction">
+  <title>Transaction Management</title>
+
+  <para>
+   It is not possible to run transaction control commands such
+   as <command>COMMIT</command> and <command>ROLLBACK</command> through SPI
+   functions such as <function>SPI_execute</function>.  There are, however,
+   separate interface functions that allow transaction control through SPI.
+  </para>
+
+  <para>
+   It is not generally safe and sensible to start and end transactions in
+   arbitrary user-defined SQL-callable functions without taking into account
+   the context in which they are called.  For example, a transaction boundary
+   in the middle of a function that is part of a complex SQL expression that
+   is part of some SQL command will probably result in obscure internal errors
+   or crashes.  The interface functions presented here are primarily intended
+   to be used by procedural language implementations to support transaction
+   management in procedures that are invoked by the <command>CALL</command>
+   command, taking the context of the <command>CALL</command> invocation into
+   account.  SPI procedures implemented in C can implement the same logic, but
+   the details of that are beyond the scope of this documentation.
+  </para>
+
+<!-- *********************************************** -->
+
+<refentry id="spi-spi-commit">
+ <indexterm><primary>SPI_commit</primary></indexterm>
+
+ <refmeta>
+  <refentrytitle>SPI_commit</refentrytitle>
+  <manvolnum>3</manvolnum>
+ </refmeta>
+
+ <refnamediv>
+  <refname>SPI_commit</refname>
+  <refpurpose>commit the current transaction</refpurpose>
+ </refnamediv>
+
+ <refsynopsisdiv>
+<synopsis>
+int SPI_commit(void)
+</synopsis>
+ </refsynopsisdiv>
+
+ <refsect1>
+  <title>Description</title>
+
+  <para>
+   <function>SPI_commit</function> commits the current transaction.  It is
+   approximately equivalent to running the SQL
+   command <command>COMMIT</command>.  After a transaction is committed, a new
+   transaction has to be started
+   using <function>SPI_start_transaction</function> before further database
+   actions can be executed.
+  </para>
+
+  <para>
+   Before this function can be
+   executed, <function>SPI_set_nonatomic</function> has to be called for the
+   current SPI connection.
+  </para>
+ </refsect1>
+
+ <refsect1>
+  <title>Return Value</title>
+
+  <para>
+   0 on success
+  </para>
+ </refsect1>
+</refentry>
+
+<!-- *********************************************** -->
+
+<refentry id="spi-spi-rollback">
+ <indexterm><primary>SPI_rollback</primary></indexterm>
+
+ <refmeta>
+  <refentrytitle>SPI_rollback</refentrytitle>
+  <manvolnum>3</manvolnum>
+ </refmeta>
+
+ <refnamediv>
+  <refname>SPI_rollback</refname>
+  <refpurpose>abort the current transaction</refpurpose>
+ </refnamediv>
+
+ <refsynopsisdiv>
+<synopsis>
+int SPI_rollback(void)
+</synopsis>
+ </refsynopsisdiv>
+
+ <refsect1>
+  <title>Description</title>
+
+  <para>
+   <function>SPI_rollback</function> rolls back the current transaction.  It
+   is approximately equivalent to running the SQL
+   command <command>ROLLBACK</command>.  After a transaction is rolled back, a
+   new transaction has to be started
+   using <function>SPI_start_transaction</function> before further database
+   actions can be executed.
+  </para>
+
+  <para>
+   Before this function can be
+   executed, <function>SPI_set_nonatomic</function> has to be called for the
+   current SPI connection.
+  </para>
+ </refsect1>
+
+ <refsect1>
+  <title>Return Value</title>
+
+  <para>
+   0 on success
+  </para>
+ </refsect1>
+</refentry>
+
+<!-- *********************************************** -->
+
+<refentry id="spi-spi-set-nonatomic">
+ <indexterm><primary>SPI_set_nonatomic</primary></indexterm>
+
+ <refmeta>
+  <refentrytitle>SPI_set_nonatomic</refentrytitle>
+  <manvolnum>3</manvolnum>
+ </refmeta>
+
+ <refnamediv>
+  <refname>SPI_set_nonatomic</refname>
+  <refpurpose>makes current SPI connection nonatomic</refpurpose>
+ </refnamediv>
+
+ <refsynopsisdiv>
+<synopsis>
+int SPI_set_nonatomic(void)
+</synopsis>
+ </refsynopsisdiv>
+
+ <refsect1>
+  <title>Description</title>
+
+  <para>
+   <function>SPI_set_nonatomic</function> sets the current SPI connection to
+   be <firstterm>nonatomic</firstterm>, which means that transaction control
+   calls <function>SPI_commit</function>, <function>SPI_rollback</function>,
+   and <function>SPI_start_transaction</function> are allowed.  Otherwise,
+   calling these functions will result in an immediate
+   error.  <function>SPI_set_nonatomic</function> has to be called
+   after <function>SPI_connect</function> and its effects are canceled by the
+   corresponding <function>SPI_finish</function>, but it can be called at any
+   point in between.
+  </para>
+ </refsect1>
+
+ <refsect1>
+  <title>Return Value</title>
+
+  <para>
+   0 on success
+  </para>
+ </refsect1>
+</refentry>
+
+<!-- *********************************************** -->
+
+<refentry id="spi-spi-start-transaction">
+ <indexterm><primary>SPI_start_transaction</primary></indexterm>
+
+ <refmeta>
+  <refentrytitle>SPI_start_transaction</refentrytitle>
+  <manvolnum>3</manvolnum>
+ </refmeta>
+
+ <refnamediv>
+  <refname>SPI_start_transaction</refname>
+  <refpurpose>start a new transaction</refpurpose>
+ </refnamediv>
+
+ <refsynopsisdiv>
+<synopsis>
+int SPI_start_transaction(void)
+</synopsis>
+ </refsynopsisdiv>
+
+ <refsect1>
+  <title>Description</title>
+
+  <para>
+   <function>SPI_start_transaction</function> starts a new transaction.  It
+   can only be called after <function>SPI_commit</function>
+   or <function>SPI_rollback</function>, as there is no transaction active at
+   that point.  Normally, when an SPI procedure is called, there is already a
+   transaction active, so attempting to start another one before closing out
+   the current one will result in an error.
+  </para>
+
+  <para>
+   Before this function can be
+   executed, <function>SPI_set_nonatomic</function> has to be called for the
+   current SPI connection.
+  </para>
+ </refsect1>
+
+ <refsect1>
+  <title>Return Value</title>
+
+  <para>
+   0 on success
+  </para>
+ </refsect1>
+</refentry>
+
+ </sect1>
+
  <sect1 id="spi-visibility">
   <title>Visibility of Data Changes</title>
 
diff --git a/src/backend/commands/functioncmds.c 
b/src/backend/commands/functioncmds.c
index 2a9c90133d..4101817c5e 100644
--- a/src/backend/commands/functioncmds.c
+++ b/src/backend/commands/functioncmds.c
@@ -65,6 +65,7 @@
 #include "utils/fmgroids.h"
 #include "utils/guc.h"
 #include "utils/lsyscache.h"
+#include "utils/memutils.h"
 #include "utils/rel.h"
 #include "utils/syscache.h"
 #include "utils/tqual.h"
@@ -2138,7 +2139,7 @@ IsThereFunctionInNamespace(const char *proname, int 
pronargs,
  *             Execute inline procedural-language code
  */
 void
-ExecuteDoStmt(DoStmt *stmt)
+ExecuteDoStmt(DoStmt *stmt, bool atomic)
 {
        InlineCodeBlock *codeblock = makeNode(InlineCodeBlock);
        ListCell   *arg;
@@ -2200,6 +2201,7 @@ ExecuteDoStmt(DoStmt *stmt)
        codeblock->langOid = HeapTupleGetOid(languageTuple);
        languageStruct = (Form_pg_language) GETSTRUCT(languageTuple);
        codeblock->langIsTrusted = languageStruct->lanpltrusted;
+       codeblock->atomic = atomic;
 
        if (languageStruct->lanpltrusted)
        {
@@ -2236,9 +2238,28 @@ ExecuteDoStmt(DoStmt *stmt)
 
 /*
  * Execute CALL statement
+ *
+ * Inside a top-level CALL statement, transaction-terminating commands such as
+ * COMMIT or a PL-specific equivalent are allowed.  The terminology in the SQL
+ * standard is that CALL establishes a non-atomic execution context.  Most
+ * other commands establish an atomic execution context, in which transaction
+ * control actions are not allowed.  If there are nested executions of CALL,
+ * we want to track the execution context recursively, so that the nested
+ * CALLs can also do transaction control.  Note, however, that for example in
+ * CALL -> SELECT -> CALL, the second call cannot do transaction control,
+ * because the SELECT in between establishes an atomic execution context.
+ *
+ * So when ExecuteCallStmt() is called from the top level, we pass in atomic =
+ * false (recall that that means transactions = yes).  We then create a
+ * CallContext node with content atomic = false, which is passed in the
+ * fcinfo->context field to the procedure invocation.  The language
+ * implementation should then take appropriate measures to allow or prevent
+ * transaction commands based on that information, e.g., call
+ * SPI_set_nonatomic().  The language should also pass on the atomic flag to
+ * any recursive invocations to CALL.
  */
 void
-ExecuteCallStmt(ParseState *pstate, CallStmt *stmt)
+ExecuteCallStmt(ParseState *pstate, CallStmt *stmt, bool atomic)
 {
        List       *targs;
        ListCell   *lc;
@@ -2249,6 +2270,8 @@ ExecuteCallStmt(ParseState *pstate, CallStmt *stmt)
        AclResult   aclresult;
        FmgrInfo        flinfo;
        FunctionCallInfoData fcinfo;
+       CallContext *callcontext;
+       HeapTuple       tp;
 
        targs = NIL;
        foreach(lc, stmt->funccall->args)
@@ -2284,8 +2307,24 @@ ExecuteCallStmt(ParseState *pstate, CallStmt *stmt)
                                                           FUNC_MAX_ARGS,
                                                           FUNC_MAX_ARGS)));
 
+       callcontext = makeNode(CallContext);
+       callcontext->atomic = atomic;
+
+       /*
+        * If proconfig is set we can't allow transaction commands because of 
the
+        * way the GUC stacking works: The transaction boundary would have to 
pop
+        * the proconfig setting off the stack.  That restriction could be 
lifted
+        * by redesigning the GUC nesting mechanism a bit.
+        */
+       tp = SearchSysCache1(PROCOID, ObjectIdGetDatum(fexpr->funcid));
+       if (!HeapTupleIsValid(tp))
+               elog(ERROR, "cache lookup failed for function %u", 
fexpr->funcid);
+       if (!heap_attisnull(tp, Anum_pg_proc_proconfig))
+               callcontext->atomic = true;
+       ReleaseSysCache(tp);
+
        fmgr_info(fexpr->funcid, &flinfo);
-       InitFunctionCallInfoData(fcinfo, &flinfo, nargs, fexpr->inputcollid, 
NULL, NULL);
+       InitFunctionCallInfoData(fcinfo, &flinfo, nargs, fexpr->inputcollid, 
(Node *) callcontext, NULL);
 
        i = 0;
        foreach (lc, fexpr->args)
diff --git a/src/backend/executor/spi.c b/src/backend/executor/spi.c
index 2da1cac3e2..57c689c60b 100644
--- a/src/backend/executor/spi.c
+++ b/src/backend/executor/spi.c
@@ -92,7 +92,7 @@ SPI_connect(void)
                        elog(ERROR, "SPI stack corrupted");
                newdepth = 16;
                _SPI_stack = (_SPI_connection *)
-                       MemoryContextAlloc(TopTransactionContext,
+                       MemoryContextAlloc(TopMemoryContext,
                                                           newdepth * 
sizeof(_SPI_connection));
                _SPI_stack_depth = newdepth;
        }
@@ -124,6 +124,7 @@ SPI_connect(void)
        _SPI_current->execCxt = NULL;
        _SPI_current->connectSubid = GetCurrentSubTransactionId();
        _SPI_current->queryEnv = NULL;
+       _SPI_current->atomic = true;    /* until told otherwise */
 
        /*
         * Create memory contexts for this procedure
@@ -133,10 +134,10 @@ SPI_connect(void)
         * Perhaps CurTransactionContext would do?      For now it doesn't 
matter
         * because we clean up explicitly in AtEOSubXact_SPI().
         */
-       _SPI_current->procCxt = AllocSetContextCreate(TopTransactionContext,
+       _SPI_current->procCxt = AllocSetContextCreate(PortalContext,
                                                                                
                  "SPI Proc",
                                                                                
                  ALLOCSET_DEFAULT_SIZES);
-       _SPI_current->execCxt = AllocSetContextCreate(TopTransactionContext,
+       _SPI_current->execCxt = AllocSetContextCreate(_SPI_current->procCxt,
                                                                                
                  "SPI Exec",
                                                                                
                  ALLOCSET_DEFAULT_SIZES);
        /* ... and switch to procedure's context */
@@ -145,6 +146,17 @@ SPI_connect(void)
        return SPI_OK_CONNECT;
 }
 
+int
+SPI_set_nonatomic(void)
+{
+       if (_SPI_current == NULL)
+               return SPI_ERROR_UNCONNECTED;
+
+       _SPI_current->atomic = false;
+
+       return SPI_OK_CONNECT;
+}
+
 int
 SPI_finish(void)
 {
@@ -158,8 +170,6 @@ SPI_finish(void)
        MemoryContextSwitchTo(_SPI_current->savedcxt);
 
        /* Release memory used in procedure call (including tuptables) */
-       MemoryContextDelete(_SPI_current->execCxt);
-       _SPI_current->execCxt = NULL;
        MemoryContextDelete(_SPI_current->procCxt);
        _SPI_current->procCxt = NULL;
 
@@ -181,12 +191,87 @@ SPI_finish(void)
        return SPI_OK_FINISH;
 }
 
+int
+SPI_start_transaction(void)
+{
+       MemoryContext oldcontext = CurrentMemoryContext;
+
+       StartTransactionCommand();
+       MemoryContextSwitchTo(oldcontext);
+       return 0;
+}
+
+int
+SPI_commit(void)
+{
+       MemoryContext oldcontext = CurrentMemoryContext;
+
+       if (_SPI_current->atomic)
+               ereport(ERROR,
+                               
(errcode(ERRCODE_INVALID_TRANSACTION_TERMINATION),
+                                errmsg("invalid transaction termination")));
+
+       /*
+        * This restriction is particular to PLs implemented on top of SPI.  
They
+        * use subtransactions to establish exception blocks that are supposed 
to
+        * be rolled back together if there is an error.  Terminating the
+        * top-level transaction in such a block violates that idea.  A future 
PL
+        * implementation might have different ideas about this, in which case
+        * this restriction would have to be refined or the check possibly be
+        * moved out of SPI into the PLs.
+        */
+       if (IsSubTransaction())
+               ereport(ERROR,
+                               
(errcode(ERRCODE_INVALID_TRANSACTION_TERMINATION),
+                                errmsg("cannot commit while a subtransaction 
is active")));
+
+       _SPI_current->internal_xact = true;
+
+       if (ActiveSnapshotSet())
+               PopActiveSnapshot();
+       CommitTransactionCommand();
+       MemoryContextSwitchTo(oldcontext);
+
+       _SPI_current->internal_xact = false;
+
+       return 0;
+}
+
+int
+SPI_rollback(void)
+{
+       MemoryContext oldcontext = CurrentMemoryContext;
+
+       if (_SPI_current->atomic)
+               ereport(ERROR,
+                               
(errcode(ERRCODE_INVALID_TRANSACTION_TERMINATION),
+                                errmsg("invalid transaction termination")));
+
+       /* see under SPI_commit() */
+       if (IsSubTransaction())
+               ereport(ERROR,
+                               
(errcode(ERRCODE_INVALID_TRANSACTION_TERMINATION),
+                                errmsg("cannot roll back while a 
subtransaction is active")));
+
+       _SPI_current->internal_xact = true;
+
+       AbortCurrentTransaction();
+       MemoryContextSwitchTo(oldcontext);
+
+       _SPI_current->internal_xact = false;
+
+       return 0;
+}
+
 /*
  * Clean up SPI state at transaction commit or abort.
  */
 void
 AtEOXact_SPI(bool isCommit)
 {
+       if (_SPI_current && _SPI_current->internal_xact)
+               return;
+
        /*
         * Note that memory contexts belonging to SPI stack entries will be 
freed
         * automatically, so we can ignore them here.  We just need to restore 
our
@@ -224,21 +309,10 @@ AtEOSubXact_SPI(bool isCommit, SubTransactionId mySubid)
                if (connection->connectSubid != mySubid)
                        break;                          /* couldn't be any 
underneath it either */
 
-               found = true;
+               if (connection->internal_xact)
+                       break;
 
-               /*
-                * Release procedure memory explicitly (see note in SPI_connect)
-                */
-               if (connection->execCxt)
-               {
-                       MemoryContextDelete(connection->execCxt);
-                       connection->execCxt = NULL;
-               }
-               if (connection->procCxt)
-               {
-                       MemoryContextDelete(connection->procCxt);
-                       connection->procCxt = NULL;
-               }
+               found = true;
 
                /*
                 * Pop the stack entry and reset global variables.  Unlike
diff --git a/src/backend/tcop/utility.c b/src/backend/tcop/utility.c
index 4da1f8f643..35f018c8da 100644
--- a/src/backend/tcop/utility.c
+++ b/src/backend/tcop/utility.c
@@ -529,7 +529,8 @@ standard_ProcessUtility(PlannedStmt *pstmt,
                        break;
 
                case T_DoStmt:
-                       ExecuteDoStmt((DoStmt *) parsetree);
+                       ExecuteDoStmt((DoStmt *) parsetree,
+                                                 (context != 
PROCESS_UTILITY_TOPLEVEL || IsTransactionBlock()));
                        break;
 
                case T_CreateTableSpaceStmt:
@@ -658,7 +659,8 @@ standard_ProcessUtility(PlannedStmt *pstmt,
                        break;
 
                case T_CallStmt:
-                       ExecuteCallStmt(pstate, castNode(CallStmt, parsetree));
+                       ExecuteCallStmt(pstate, castNode(CallStmt, parsetree),
+                                                       (context != 
PROCESS_UTILITY_TOPLEVEL || IsTransactionBlock()));
                        break;
 
                case T_ClusterStmt:
diff --git a/src/backend/utils/mmgr/portalmem.c 
b/src/backend/utils/mmgr/portalmem.c
index d03b779407..d750425852 100644
--- a/src/backend/utils/mmgr/portalmem.c
+++ b/src/backend/utils/mmgr/portalmem.c
@@ -736,11 +736,8 @@ PreCommit_Portals(bool isPrepare)
 /*
  * Abort processing for portals.
  *
- * At this point we reset "active" status and run the cleanup hook if
- * present, but we can't release the portal's memory until the cleanup call.
- *
- * The reason we need to reset active is so that we can replace the unnamed
- * portal, else we'll fail to execute ROLLBACK when it arrives.
+ * At this point we run the cleanup hook if present, but we can't release the
+ * portal's memory until the cleanup call.
  */
 void
 AtAbort_Portals(void)
@@ -754,17 +751,6 @@ AtAbort_Portals(void)
        {
                Portal          portal = hentry->portal;
 
-               /*
-                * See similar code in AtSubAbort_Portals().  This would fire 
if code
-                * orchestrating multiple top-level transactions within a 
portal, such
-                * as VACUUM, caught errors and continued under the same portal 
with a
-                * fresh transaction.  No part of core PostgreSQL functions 
that way.
-                * XXX Such code would wish the portal to remain ACTIVE, as in
-                * PreCommit_Portals().
-                */
-               if (portal->status == PORTAL_ACTIVE)
-                       MarkPortalFailed(portal);
-
                /*
                 * Do nothing else to cursors held over from a previous 
transaction.
                 */
@@ -799,14 +785,6 @@ AtAbort_Portals(void)
                 * PortalDrop.
                 */
                portal->resowner = NULL;
-
-               /*
-                * Although we can't delete the portal data structure proper, 
we can
-                * release any memory in subsidiary contexts, such as executor 
state.
-                * The cleanup hook was the last thing that might have needed 
data
-                * there.
-                */
-               MemoryContextDeleteChildren(PortalGetHeapMemory(portal));
        }
 }
 
@@ -826,6 +804,19 @@ AtCleanup_Portals(void)
        {
                Portal          portal = hentry->portal;
 
+               /*
+                * Do not touch active portals --- this can only happen in the 
case of
+                * a multi-transaction command.
+                *
+                * Note however that any resource owner attached to such a 
portal is
+                * still going to go away, so don't leave a dangling pointer.
+                */
+               if (portal->status == PORTAL_ACTIVE)
+               {
+                       portal->resowner = NULL;
+                       continue;
+               }
+
                /* Do nothing to cursors held over from a previous transaction 
*/
                if (portal->createSubid == InvalidSubTransactionId)
                {
@@ -1155,3 +1146,22 @@ ThereAreNoReadyPortals(void)
 
        return true;
 }
+
+bool
+ThereArePinnedPortals(void)
+{
+       HASH_SEQ_STATUS status;
+       PortalHashEnt *hentry;
+
+       hash_seq_init(&status, PortalHashTable);
+
+       while ((hentry = (PortalHashEnt *) hash_seq_search(&status)) != NULL)
+       {
+               Portal          portal = hentry->portal;
+
+               if (portal->portalPinned)
+                       return true;
+       }
+
+       return false;
+}
diff --git a/src/include/commands/defrem.h b/src/include/commands/defrem.h
index 52cbf61ccb..b03f5b6a95 100644
--- a/src/include/commands/defrem.h
+++ b/src/include/commands/defrem.h
@@ -58,8 +58,8 @@ extern ObjectAddress CreateTransform(CreateTransformStmt 
*stmt);
 extern void DropTransformById(Oid transformOid);
 extern void IsThereFunctionInNamespace(const char *proname, int pronargs,
                                                   oidvector *proargtypes, Oid 
nspOid);
-extern void ExecuteDoStmt(DoStmt *stmt);
-extern void ExecuteCallStmt(ParseState *pstate, CallStmt *stmt);
+extern void ExecuteDoStmt(DoStmt *stmt, bool atomic);
+extern void ExecuteCallStmt(ParseState *pstate, CallStmt *stmt, bool atomic);
 extern Oid     get_cast_oid(Oid sourcetypeid, Oid targettypeid, bool 
missing_ok);
 extern Oid     get_transform_oid(Oid type_id, Oid lang_id, bool missing_ok);
 extern void interpret_function_parameter_list(ParseState *pstate,
diff --git a/src/include/executor/spi.h b/src/include/executor/spi.h
index acade7e92e..e38158c54e 100644
--- a/src/include/executor/spi.h
+++ b/src/include/executor/spi.h
@@ -78,6 +78,7 @@ extern PGDLLIMPORT SPITupleTable *SPI_tuptable;
 extern PGDLLIMPORT int SPI_result;
 
 extern int     SPI_connect(void);
+extern int     SPI_set_nonatomic(void);
 extern int     SPI_finish(void);
 extern int     SPI_execute(const char *src, bool read_only, long tcount);
 extern int SPI_execute_plan(SPIPlanPtr plan, Datum *Values, const char *Nulls,
@@ -156,6 +157,10 @@ extern int SPI_register_relation(EphemeralNamedRelation 
enr);
 extern int     SPI_unregister_relation(const char *name);
 extern int     SPI_register_trigger_data(TriggerData *tdata);
 
+extern int     SPI_start_transaction(void);
+extern int     SPI_commit(void);
+extern int     SPI_rollback(void);
+
 extern void AtEOXact_SPI(bool isCommit);
 extern void AtEOSubXact_SPI(bool isCommit, SubTransactionId mySubid);
 
diff --git a/src/include/executor/spi_priv.h b/src/include/executor/spi_priv.h
index 8fae755418..9dc8af22e4 100644
--- a/src/include/executor/spi_priv.h
+++ b/src/include/executor/spi_priv.h
@@ -36,6 +36,10 @@ typedef struct
        MemoryContext savedcxt;         /* context of SPI_connect's caller */
        SubTransactionId connectSubid;  /* ID of connecting subtransaction */
        QueryEnvironment *queryEnv; /* query environment setup for SPI level */
+
+       /* transaction management support */
+       bool            atomic;                 /* atomic execution context, 
does not allow transactions */
+       bool            internal_xact;  /* SPI-managed transaction boundary, 
skip cleanup */
 } _SPI_connection;
 
 /*
diff --git a/src/include/nodes/nodes.h b/src/include/nodes/nodes.h
index c5b5115f5b..6dcd51e958 100644
--- a/src/include/nodes/nodes.h
+++ b/src/include/nodes/nodes.h
@@ -500,7 +500,8 @@ typedef enum NodeTag
        T_FdwRoutine,                           /* in foreign/fdwapi.h */
        T_IndexAmRoutine,                       /* in access/amapi.h */
        T_TsmRoutine,                           /* in access/tsmapi.h */
-       T_ForeignKeyCacheInfo           /* in utils/rel.h */
+       T_ForeignKeyCacheInfo,          /* in utils/rel.h */
+       T_CallContext                           /* in nodes/parsenodes.h */
 } NodeTag;
 
 /*
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 2eaa6b2774..cb1afd68f8 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -2803,6 +2803,7 @@ typedef struct InlineCodeBlock
        char       *source_text;        /* source text of anonymous code block 
*/
        Oid                     langOid;                /* OID of selected 
language */
        bool            langIsTrusted;  /* trusted property of the language */
+       bool            atomic;                 /* atomic execution context */
 } InlineCodeBlock;
 
 /* ----------------------
@@ -2815,6 +2816,12 @@ typedef struct CallStmt
        FuncCall   *funccall;
 } CallStmt;
 
+typedef struct CallContext
+{
+       NodeTag         type;
+       bool            atomic;
+} CallContext;
+
 /* ----------------------
  *             Alter Object Rename Statement
  * ----------------------
diff --git a/src/include/utils/portal.h b/src/include/utils/portal.h
index cb6f00081d..cdbe7323d8 100644
--- a/src/include/utils/portal.h
+++ b/src/include/utils/portal.h
@@ -237,5 +237,6 @@ extern PlannedStmt *PortalGetPrimaryStmt(Portal portal);
 extern void PortalCreateHoldStore(Portal portal);
 extern void PortalHashTableDeleteAll(void);
 extern bool ThereAreNoReadyPortals(void);
+extern bool ThereArePinnedPortals(void);
 
 #endif                                                 /* PORTAL_H */
diff --git a/src/pl/plperl/GNUmakefile b/src/pl/plperl/GNUmakefile
index b829027d05..933abb47c4 100644
--- a/src/pl/plperl/GNUmakefile
+++ b/src/pl/plperl/GNUmakefile
@@ -55,7 +55,7 @@ endif # win32
 SHLIB_LINK = $(perl_embed_ldflags)
 
 REGRESS_OPTS = --dbname=$(PL_TESTDB) --load-extension=plperl  
--load-extension=plperlu
-REGRESS = plperl plperl_lc plperl_trigger plperl_shared plperl_elog 
plperl_util plperl_init plperlu plperl_array plperl_call
+REGRESS = plperl plperl_lc plperl_trigger plperl_shared plperl_elog 
plperl_util plperl_init plperlu plperl_array plperl_call plperl_transaction
 # if Perl can support two interpreters in one backend,
 # test plperl-and-plperlu cases
 ifneq ($(PERL),)
diff --git a/src/pl/plperl/SPI.xs b/src/pl/plperl/SPI.xs
index d9e6f579d4..dc9ddedc8f 100644
--- a/src/pl/plperl/SPI.xs
+++ b/src/pl/plperl/SPI.xs
@@ -17,6 +17,7 @@
 #define PG_NEED_PERL_XSUB_H
 #include "plperl.h"
 #include "plperl_helpers.h"
+#include "executor/spi.h"
 
 
 MODULE = PostgreSQL::InServer::SPI PREFIX = spi_
@@ -152,6 +153,17 @@ spi_spi_cursor_close(sv)
                plperl_spi_cursor_close(cursor);
                pfree(cursor);
 
+void
+spi_spi_commit()
+       CODE:
+               SPI_commit();
+               SPI_start_transaction();
+
+void
+spi_spi_rollback()
+       CODE:
+               SPI_rollback();
+               SPI_start_transaction();
 
 BOOT:
     items = 0;  /* avoid 'unused variable' warning */
diff --git a/src/pl/plperl/expected/plperl_transaction.out 
b/src/pl/plperl/expected/plperl_transaction.out
new file mode 100644
index 0000000000..f7378ce600
--- /dev/null
+++ b/src/pl/plperl/expected/plperl_transaction.out
@@ -0,0 +1,94 @@
+CREATE TABLE test1 (a int, b text);
+CREATE PROCEDURE transaction_test1()
+LANGUAGE plperl
+AS $$
+foreach my $i (0..9) {
+    spi_exec_query("INSERT INTO test1 (a) VALUES ($i)");
+    if ($i % 2 == 0) {
+        spi_commit();
+    } else {
+        spi_rollback();
+    }
+}
+$$;
+CALL transaction_test1();
+SELECT * FROM test1;
+ a | b 
+---+---
+ 0 | 
+ 2 | 
+ 4 | 
+ 6 | 
+ 8 | 
+(5 rows)
+
+TRUNCATE test1;
+DO
+LANGUAGE plperl
+$$
+foreach my $i (0..9) {
+    spi_exec_query("INSERT INTO test1 (a) VALUES ($i)");
+    if ($i % 2 == 0) {
+        spi_commit();
+    } else {
+        spi_rollback();
+    }
+}
+$$;
+SELECT * FROM test1;
+ a | b 
+---+---
+ 0 | 
+ 2 | 
+ 4 | 
+ 6 | 
+ 8 | 
+(5 rows)
+
+TRUNCATE test1;
+-- not allowed in a function
+CREATE FUNCTION transaction_test2() RETURNS int
+LANGUAGE plperl
+AS $$
+foreach my $i (0..9) {
+    spi_exec_query("INSERT INTO test1 (a) VALUES ($i)");
+    if ($i % 2 == 0) {
+        spi_commit();
+    } else {
+        spi_rollback();
+    }
+}
+return 1;
+$$;
+SELECT transaction_test2();
+ERROR:  invalid transaction termination
+CONTEXT:  PL/Perl function "transaction_test2"
+SELECT * FROM test1;
+ a | b 
+---+---
+(0 rows)
+
+-- also not allowed if procedure is called from a function
+CREATE FUNCTION transaction_test3() RETURNS int
+LANGUAGE plperl
+AS $$
+spi_exec_query("CALL transaction_test1()");
+return 1;
+$$;
+-- FIXME
+--SELECT transaction_test3();
+SELECT * FROM test1;
+ a | b 
+---+---
+(0 rows)
+
+-- DO block inside function
+CREATE FUNCTION transaction_test4() RETURNS int
+LANGUAGE plperl
+AS $$
+spi_exec_query('DO LANGUAGE plperl $x$ spi_commit(); $x$');
+return 1;
+$$;
+-- FIXME
+--SELECT transaction_test4();
+DROP TABLE test1;
diff --git a/src/pl/plperl/plperl.c b/src/pl/plperl/plperl.c
index 9f5313235f..68592033f7 100644
--- a/src/pl/plperl/plperl.c
+++ b/src/pl/plperl/plperl.c
@@ -1931,6 +1931,8 @@ plperl_inline_handler(PG_FUNCTION_ARGS)
 
                if (SPI_connect() != SPI_OK_CONNECT)
                        elog(ERROR, "could not connect to SPI manager");
+               if (!codeblock->atomic)
+                       SPI_set_nonatomic();
 
                select_perl_context(desc.lanpltrusted);
 
@@ -2409,6 +2411,10 @@ plperl_func_handler(PG_FUNCTION_ARGS)
        current_call_data->prodesc = prodesc;
        increment_prodesc_refcount(prodesc);
 
+       if (prodesc->result_oid == InvalidOid &&
+               !castNode(CallContext, fcinfo->context)->atomic)
+               SPI_set_nonatomic();
+
        /* Set a callback for error reporting */
        pl_error_context.callback = plperl_exec_callback;
        pl_error_context.previous = error_context_stack;
diff --git a/src/pl/plperl/sql/plperl_transaction.sql 
b/src/pl/plperl/sql/plperl_transaction.sql
new file mode 100644
index 0000000000..5f15691cfc
--- /dev/null
+++ b/src/pl/plperl/sql/plperl_transaction.sql
@@ -0,0 +1,88 @@
+CREATE TABLE test1 (a int, b text);
+
+
+CREATE PROCEDURE transaction_test1()
+LANGUAGE plperl
+AS $$
+foreach my $i (0..9) {
+    spi_exec_query("INSERT INTO test1 (a) VALUES ($i)");
+    if ($i % 2 == 0) {
+        spi_commit();
+    } else {
+        spi_rollback();
+    }
+}
+$$;
+
+CALL transaction_test1();
+
+SELECT * FROM test1;
+
+
+TRUNCATE test1;
+
+DO
+LANGUAGE plperl
+$$
+foreach my $i (0..9) {
+    spi_exec_query("INSERT INTO test1 (a) VALUES ($i)");
+    if ($i % 2 == 0) {
+        spi_commit();
+    } else {
+        spi_rollback();
+    }
+}
+$$;
+
+SELECT * FROM test1;
+
+
+TRUNCATE test1;
+
+-- not allowed in a function
+CREATE FUNCTION transaction_test2() RETURNS int
+LANGUAGE plperl
+AS $$
+foreach my $i (0..9) {
+    spi_exec_query("INSERT INTO test1 (a) VALUES ($i)");
+    if ($i % 2 == 0) {
+        spi_commit();
+    } else {
+        spi_rollback();
+    }
+}
+return 1;
+$$;
+
+SELECT transaction_test2();
+
+SELECT * FROM test1;
+
+
+-- also not allowed if procedure is called from a function
+CREATE FUNCTION transaction_test3() RETURNS int
+LANGUAGE plperl
+AS $$
+spi_exec_query("CALL transaction_test1()");
+return 1;
+$$;
+
+-- FIXME
+--SELECT transaction_test3();
+
+SELECT * FROM test1;
+
+
+-- DO block inside function
+CREATE FUNCTION transaction_test4() RETURNS int
+LANGUAGE plperl
+AS $$
+spi_exec_query('DO LANGUAGE plperl $x$ spi_commit(); $x$');
+return 1;
+$$;
+
+-- FIXME
+--SELECT transaction_test4();
+
+
+DROP TABLE test1;
diff --git a/src/pl/plpgsql/src/pl_exec.c b/src/pl/plpgsql/src/pl_exec.c
index ec480cb0ba..b8b0df21de 100644
--- a/src/pl/plpgsql/src/pl_exec.c
+++ b/src/pl/plpgsql/src/pl_exec.c
@@ -215,6 +215,10 @@ static int exec_stmt_dynexecute(PLpgSQL_execstate *estate,
                                         PLpgSQL_stmt_dynexecute *stmt);
 static int exec_stmt_dynfors(PLpgSQL_execstate *estate,
                                  PLpgSQL_stmt_dynfors *stmt);
+static int exec_stmt_commit(PLpgSQL_execstate *estate,
+                               PLpgSQL_stmt_commit *stmt);
+static int exec_stmt_rollback(PLpgSQL_execstate *estate,
+                               PLpgSQL_stmt_rollback *stmt);
 
 static void plpgsql_estate_setup(PLpgSQL_execstate *estate,
                                         PLpgSQL_function *func,
@@ -1652,6 +1656,14 @@ exec_stmt(PLpgSQL_execstate *estate, PLpgSQL_stmt *stmt)
                        rc = exec_stmt_close(estate, (PLpgSQL_stmt_close *) 
stmt);
                        break;
 
+               case PLPGSQL_STMT_COMMIT:
+                       rc = exec_stmt_commit(estate, (PLpgSQL_stmt_commit *) 
stmt);
+                       break;
+
+               case PLPGSQL_STMT_ROLLBACK:
+                       rc = exec_stmt_rollback(estate, (PLpgSQL_stmt_rollback 
*) stmt);
+                       break;
+
                default:
                        estate->err_stmt = save_estmt;
                        elog(ERROR, "unrecognized cmdtype: %d", stmt->cmd_type);
@@ -4356,6 +4368,57 @@ exec_stmt_close(PLpgSQL_execstate *estate, 
PLpgSQL_stmt_close *stmt)
        return PLPGSQL_RC_OK;
 }
 
+/*
+ * exec_stmt_commit
+ *
+ * Commit the transaction.
+ */
+static int
+exec_stmt_commit(PLpgSQL_execstate *estate, PLpgSQL_stmt_commit *stmt)
+{
+       /*
+        * XXX This could be implemented by converting the pinned portals to
+        * holdable ones and organizing the cleanup separately.
+        */
+       if (ThereArePinnedPortals())
+               ereport(ERROR,
+                               (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+                                errmsg("committing inside a cursor loop is not 
supported")));
+
+       SPI_commit();
+       SPI_start_transaction();
+
+       estate->simple_eval_estate = NULL;
+       plpgsql_create_econtext(estate);
+
+       return PLPGSQL_RC_OK;
+}
+
+/*
+ * exec_stmt_rollback
+ *
+ * Abort the transaction.
+ */
+static int
+exec_stmt_rollback(PLpgSQL_execstate *estate, PLpgSQL_stmt_rollback *stmt)
+{
+       /*
+        * Unlike the COMMIT case above, this might not make sense at all,
+        * especially if the query driving the cursor loop has side effects.
+        */
+       if (ThereArePinnedPortals())
+               ereport(ERROR,
+                               
(errcode(ERRCODE_INVALID_TRANSACTION_TERMINATION),
+                                errmsg("cannot abort transaction inside a 
cursor loop")));
+
+       SPI_rollback();
+       SPI_start_transaction();
+
+       estate->simple_eval_estate = NULL;
+       plpgsql_create_econtext(estate);
+
+       return PLPGSQL_RC_OK;
+}
 
 /* ----------
  * exec_assign_expr                    Put an expression's result into a 
variable.
@@ -6857,8 +6920,7 @@ plpgsql_xact_cb(XactEvent event, void *arg)
         */
        if (event == XACT_EVENT_COMMIT || event == XACT_EVENT_PREPARE)
        {
-               /* Shouldn't be any econtext stack entries left at commit */
-               Assert(simple_econtext_stack == NULL);
+               simple_econtext_stack = NULL;
 
                if (shared_simple_eval_estate)
                        FreeExecutorState(shared_simple_eval_estate);
diff --git a/src/pl/plpgsql/src/pl_funcs.c b/src/pl/plpgsql/src/pl_funcs.c
index 23f54e1c21..a3a45916d1 100644
--- a/src/pl/plpgsql/src/pl_funcs.c
+++ b/src/pl/plpgsql/src/pl_funcs.c
@@ -284,6 +284,10 @@ plpgsql_stmt_typename(PLpgSQL_stmt *stmt)
                        return "CLOSE";
                case PLPGSQL_STMT_PERFORM:
                        return "PERFORM";
+               case PLPGSQL_STMT_COMMIT:
+                       return "COMMIT";
+               case PLPGSQL_STMT_ROLLBACK:
+                       return "ROLLBACK";
        }
 
        return "unknown";
@@ -363,6 +367,8 @@ static void free_open(PLpgSQL_stmt_open *stmt);
 static void free_fetch(PLpgSQL_stmt_fetch *stmt);
 static void free_close(PLpgSQL_stmt_close *stmt);
 static void free_perform(PLpgSQL_stmt_perform *stmt);
+static void free_commit(PLpgSQL_stmt_commit *stmt);
+static void free_rollback(PLpgSQL_stmt_rollback *stmt);
 static void free_expr(PLpgSQL_expr *expr);
 
 
@@ -443,6 +449,12 @@ free_stmt(PLpgSQL_stmt *stmt)
                case PLPGSQL_STMT_PERFORM:
                        free_perform((PLpgSQL_stmt_perform *) stmt);
                        break;
+               case PLPGSQL_STMT_COMMIT:
+                       free_commit((PLpgSQL_stmt_commit *) stmt);
+                       break;
+               case PLPGSQL_STMT_ROLLBACK:
+                       free_rollback((PLpgSQL_stmt_rollback *) stmt);
+                       break;
                default:
                        elog(ERROR, "unrecognized cmd_type: %d", 
stmt->cmd_type);
                        break;
@@ -590,6 +602,16 @@ free_perform(PLpgSQL_stmt_perform *stmt)
        free_expr(stmt->expr);
 }
 
+static void
+free_commit(PLpgSQL_stmt_commit *stmt)
+{
+}
+
+static void
+free_rollback(PLpgSQL_stmt_rollback *stmt)
+{
+}
+
 static void
 free_exit(PLpgSQL_stmt_exit *stmt)
 {
@@ -777,6 +799,8 @@ static void dump_fetch(PLpgSQL_stmt_fetch *stmt);
 static void dump_cursor_direction(PLpgSQL_stmt_fetch *stmt);
 static void dump_close(PLpgSQL_stmt_close *stmt);
 static void dump_perform(PLpgSQL_stmt_perform *stmt);
+static void dump_commit(PLpgSQL_stmt_commit *stmt);
+static void dump_rollback(PLpgSQL_stmt_rollback *stmt);
 static void dump_expr(PLpgSQL_expr *expr);
 
 
@@ -867,6 +891,12 @@ dump_stmt(PLpgSQL_stmt *stmt)
                case PLPGSQL_STMT_PERFORM:
                        dump_perform((PLpgSQL_stmt_perform *) stmt);
                        break;
+               case PLPGSQL_STMT_COMMIT:
+                       dump_commit((PLpgSQL_stmt_commit *) stmt);
+                       break;
+               case PLPGSQL_STMT_ROLLBACK:
+                       dump_rollback((PLpgSQL_stmt_rollback *) stmt);
+                       break;
                default:
                        elog(ERROR, "unrecognized cmd_type: %d", 
stmt->cmd_type);
                        break;
@@ -1243,6 +1273,20 @@ dump_perform(PLpgSQL_stmt_perform *stmt)
        printf("\n");
 }
 
+static void
+dump_commit(PLpgSQL_stmt_commit *stmt)
+{
+       dump_ind();
+       printf("COMMIT\n");
+}
+
+static void
+dump_rollback(PLpgSQL_stmt_rollback *stmt)
+{
+       dump_ind();
+       printf("ROLLBACK\n");
+}
+
 static void
 dump_exit(PLpgSQL_stmt_exit *stmt)
 {
diff --git a/src/pl/plpgsql/src/pl_gram.y b/src/pl/plpgsql/src/pl_gram.y
index 94f1f58593..e661750176 100644
--- a/src/pl/plpgsql/src/pl_gram.y
+++ b/src/pl/plpgsql/src/pl_gram.y
@@ -199,6 +199,7 @@ static      void                    
check_raise_parameters(PLpgSQL_stmt_raise *stmt);
 %type <stmt>   stmt_return stmt_raise stmt_assert stmt_execsql
 %type <stmt>   stmt_dynexecute stmt_for stmt_perform stmt_getdiag
 %type <stmt>   stmt_open stmt_fetch stmt_move stmt_close stmt_null
+%type <stmt>   stmt_commit stmt_rollback
 %type <stmt>   stmt_case stmt_foreach_a
 
 %type <list>   proc_exceptions
@@ -261,6 +262,7 @@ static      void                    
check_raise_parameters(PLpgSQL_stmt_raise *stmt);
 %token <keyword>       K_COLLATE
 %token <keyword>       K_COLUMN
 %token <keyword>       K_COLUMN_NAME
+%token <keyword>       K_COMMIT
 %token <keyword>       K_CONSTANT
 %token <keyword>       K_CONSTRAINT
 %token <keyword>       K_CONSTRAINT_NAME
@@ -326,6 +328,7 @@ static      void                    
check_raise_parameters(PLpgSQL_stmt_raise *stmt);
 %token <keyword>       K_RETURN
 %token <keyword>       K_RETURNED_SQLSTATE
 %token <keyword>       K_REVERSE
+%token <keyword>       K_ROLLBACK
 %token <keyword>       K_ROW_COUNT
 %token <keyword>       K_ROWTYPE
 %token <keyword>       K_SCHEMA
@@ -898,6 +901,10 @@ proc_stmt          : pl_block ';'
                                                { $$ = $1; }
                                | stmt_null
                                                { $$ = $1; }
+                               | stmt_commit
+                                               { $$ = $1; }
+                               | stmt_rollback
+                                               { $$ = $1; }
                                ;
 
 stmt_perform   : K_PERFORM expr_until_semi
@@ -2174,6 +2181,31 @@ stmt_null                : K_NULL ';'
                                        }
                                ;
 
+stmt_commit            : K_COMMIT ';'
+                                       {
+                                               PLpgSQL_stmt_commit *new;
+
+                                               new = 
palloc(sizeof(PLpgSQL_stmt_commit));
+                                               new->cmd_type = 
PLPGSQL_STMT_COMMIT;
+                                               new->lineno = 
plpgsql_location_to_lineno(@1);
+
+                                               $$ = (PLpgSQL_stmt *)new;
+                                       }
+                               ;
+
+stmt_rollback  : K_ROLLBACK ';'
+                                       {
+                                               PLpgSQL_stmt_rollback *new;
+
+                                               new = 
palloc(sizeof(PLpgSQL_stmt_rollback));
+                                               new->cmd_type = 
PLPGSQL_STMT_ROLLBACK;
+                                               new->lineno = 
plpgsql_location_to_lineno(@1);
+
+                                               $$ = (PLpgSQL_stmt *)new;
+                                       }
+                               ;
+
+
 cursor_variable        : T_DATUM
                                        {
                                                /*
@@ -2410,6 +2442,7 @@ unreserved_keyword        :
                                | K_COLLATE
                                | K_COLUMN
                                | K_COLUMN_NAME
+                               | K_COMMIT
                                | K_CONSTANT
                                | K_CONSTRAINT
                                | K_CONSTRAINT_NAME
@@ -2461,6 +2494,7 @@ unreserved_keyword        :
                                | K_RETURN
                                | K_RETURNED_SQLSTATE
                                | K_REVERSE
+                               | K_ROLLBACK
                                | K_ROW_COUNT
                                | K_ROWTYPE
                                | K_SCHEMA
diff --git a/src/pl/plpgsql/src/pl_handler.c b/src/pl/plpgsql/src/pl_handler.c
index 1ebb7a7b5e..6857b0375e 100644
--- a/src/pl/plpgsql/src/pl_handler.c
+++ b/src/pl/plpgsql/src/pl_handler.c
@@ -255,7 +255,12 @@ plpgsql_call_handler(PG_FUNCTION_ARGS)
                        retval = (Datum) 0;
                }
                else
+               {
+                       if (func->fn_rettype == InvalidOid &&
+                               !castNode(CallContext, fcinfo->context)->atomic)
+                               SPI_set_nonatomic();
                        retval = plpgsql_exec_function(func, fcinfo, NULL);
+               }
        }
        PG_CATCH();
        {
@@ -304,6 +309,9 @@ plpgsql_inline_handler(PG_FUNCTION_ARGS)
        if ((rc = SPI_connect()) != SPI_OK_CONNECT)
                elog(ERROR, "SPI_connect failed: %s", 
SPI_result_code_string(rc));
 
+       if (!codeblock->atomic)
+               SPI_set_nonatomic();
+
        /* Compile the anonymous code block */
        func = plpgsql_compile_inline(codeblock->source_text);
 
diff --git a/src/pl/plpgsql/src/pl_scanner.c b/src/pl/plpgsql/src/pl_scanner.c
index 553be8c93c..a172031db2 100644
--- a/src/pl/plpgsql/src/pl_scanner.c
+++ b/src/pl/plpgsql/src/pl_scanner.c
@@ -106,6 +106,7 @@ static const ScanKeyword unreserved_keywords[] = {
        PG_KEYWORD("collate", K_COLLATE, UNRESERVED_KEYWORD)
        PG_KEYWORD("column", K_COLUMN, UNRESERVED_KEYWORD)
        PG_KEYWORD("column_name", K_COLUMN_NAME, UNRESERVED_KEYWORD)
+       PG_KEYWORD("commit", K_COMMIT, UNRESERVED_KEYWORD)
        PG_KEYWORD("constant", K_CONSTANT, UNRESERVED_KEYWORD)
        PG_KEYWORD("constraint", K_CONSTRAINT, UNRESERVED_KEYWORD)
        PG_KEYWORD("constraint_name", K_CONSTRAINT_NAME, UNRESERVED_KEYWORD)
@@ -158,6 +159,7 @@ static const ScanKeyword unreserved_keywords[] = {
        PG_KEYWORD("return", K_RETURN, UNRESERVED_KEYWORD)
        PG_KEYWORD("returned_sqlstate", K_RETURNED_SQLSTATE, UNRESERVED_KEYWORD)
        PG_KEYWORD("reverse", K_REVERSE, UNRESERVED_KEYWORD)
+       PG_KEYWORD("rollback", K_ROLLBACK, UNRESERVED_KEYWORD)
        PG_KEYWORD("row_count", K_ROW_COUNT, UNRESERVED_KEYWORD)
        PG_KEYWORD("rowtype", K_ROWTYPE, UNRESERVED_KEYWORD)
        PG_KEYWORD("schema", K_SCHEMA, UNRESERVED_KEYWORD)
diff --git a/src/pl/plpgsql/src/plpgsql.h b/src/pl/plpgsql/src/plpgsql.h
index 2b19948562..8494a4374d 100644
--- a/src/pl/plpgsql/src/plpgsql.h
+++ b/src/pl/plpgsql/src/plpgsql.h
@@ -105,7 +105,9 @@ typedef enum PLpgSQL_stmt_type
        PLPGSQL_STMT_OPEN,
        PLPGSQL_STMT_FETCH,
        PLPGSQL_STMT_CLOSE,
-       PLPGSQL_STMT_PERFORM
+       PLPGSQL_STMT_PERFORM,
+       PLPGSQL_STMT_COMMIT,
+       PLPGSQL_STMT_ROLLBACK
 } PLpgSQL_stmt_type;
 
 /*
@@ -433,6 +435,24 @@ typedef struct PLpgSQL_stmt_perform
        PLpgSQL_expr *expr;
 } PLpgSQL_stmt_perform;
 
+/*
+ * COMMIT statement
+ */
+typedef struct PLpgSQL_stmt_commit
+{
+       PLpgSQL_stmt_type cmd_type;
+       int                     lineno;
+} PLpgSQL_stmt_commit;
+
+/*
+ * ROLLBACK statement
+ */
+typedef struct PLpgSQL_stmt_rollback
+{
+       PLpgSQL_stmt_type cmd_type;
+       int                     lineno;
+} PLpgSQL_stmt_rollback;
+
 /*
  * GET DIAGNOSTICS item
  */
diff --git a/src/pl/plpython/Makefile b/src/pl/plpython/Makefile
index cc91afebde..d09910835d 100644
--- a/src/pl/plpython/Makefile
+++ b/src/pl/plpython/Makefile
@@ -90,6 +90,7 @@ REGRESS = \
        plpython_quote \
        plpython_composite \
        plpython_subtransaction \
+       plpython_transaction \
        plpython_drop
 
 REGRESS_PLPYTHON3_MANGLE := $(REGRESS)
diff --git a/src/pl/plpython/expected/plpython_test.out 
b/src/pl/plpython/expected/plpython_test.out
index 847e4cc412..39b994f446 100644
--- a/src/pl/plpython/expected/plpython_test.out
+++ b/src/pl/plpython/expected/plpython_test.out
@@ -48,6 +48,7 @@ select module_contents();
  Error
  Fatal
  SPIError
+ commit
  cursor
  debug
  error
@@ -60,10 +61,11 @@ select module_contents();
  quote_ident
  quote_literal
  quote_nullable
+ rollback
  spiexceptions
  subtransaction
  warning
-(18 rows)
+(20 rows)
 
 CREATE FUNCTION elog_test_basic() RETURNS void
 AS $$
diff --git a/src/pl/plpython/expected/plpython_transaction.out 
b/src/pl/plpython/expected/plpython_transaction.out
new file mode 100644
index 0000000000..ff07bce193
--- /dev/null
+++ b/src/pl/plpython/expected/plpython_transaction.out
@@ -0,0 +1,104 @@
+CREATE TABLE test1 (a int, b text);
+CREATE PROCEDURE transaction_test1()
+LANGUAGE plpythonu
+AS $$
+for i in range(0, 10):
+    plpy.execute("INSERT INTO test1 (a) VALUES (%d)" % i)
+    if i % 2 == 0:
+        plpy.commit()
+    else:
+        plpy.rollback()
+$$;
+CALL transaction_test1();
+SELECT * FROM test1;
+ a | b 
+---+---
+ 0 | 
+ 2 | 
+ 4 | 
+ 6 | 
+ 8 | 
+(5 rows)
+
+TRUNCATE test1;
+DO
+LANGUAGE plpythonu
+$$
+for i in range(0, 10):
+    plpy.execute("INSERT INTO test1 (a) VALUES (%d)" % i)
+    if i % 2 == 0:
+        plpy.commit()
+    else:
+        plpy.rollback()
+$$;
+SELECT * FROM test1;
+ a | b 
+---+---
+ 0 | 
+ 2 | 
+ 4 | 
+ 6 | 
+ 8 | 
+(5 rows)
+
+TRUNCATE test1;
+-- not allowed in a function
+CREATE FUNCTION transaction_test2() RETURNS int
+LANGUAGE plpythonu
+AS $$
+for i in range(0, 10):
+    plpy.execute("INSERT INTO test1 (a) VALUES (%d)" % i)
+    if i % 2 == 0:
+        plpy.commit()
+    else:
+        plpy.rollback()
+return 1
+$$;
+SELECT transaction_test2();
+ERROR:  invalid transaction termination
+CONTEXT:  PL/Python function "transaction_test2"
+SELECT * FROM test1;
+ a | b 
+---+---
+(0 rows)
+
+-- also not allowed if procedure is called from a function
+CREATE FUNCTION transaction_test3() RETURNS int
+LANGUAGE plpythonu
+AS $$
+plpy.execute("CALL transaction_test1()")
+return 1
+$$;
+SELECT transaction_test3();
+ERROR:  spiexceptions.InvalidTransactionTermination: invalid transaction 
termination
+CONTEXT:  Traceback (most recent call last):
+  PL/Python function "transaction_test3", line 2, in <module>
+    plpy.execute("CALL transaction_test1()")
+PL/Python function "transaction_test3"
+SELECT * FROM test1;
+ a | b 
+---+---
+(0 rows)
+
+-- DO block inside function
+CREATE FUNCTION transaction_test4() RETURNS int
+LANGUAGE plpythonu
+AS $$
+plpy.execute("DO LANGUAGE plpythonu $x$ plpy.commit() $x$")
+return 1
+$$;
+SELECT transaction_test4();
+ERROR:  spiexceptions.InvalidTransactionTermination: invalid transaction 
termination
+CONTEXT:  Traceback (most recent call last):
+  PL/Python function "transaction_test4", line 2, in <module>
+    plpy.execute("DO LANGUAGE plpythonu $x$ plpy.commit() $x$")
+PL/Python function "transaction_test4"
+-- commit inside subtransaction (prohibited)
+DO LANGUAGE plpythonu $$
+with plpy.subtransaction():
+    plpy.commit()
+$$;
+WARNING:  forcibly aborting a subtransaction that has not been exited
+ERROR:  cannot commit while a subtransaction is active
+CONTEXT:  PL/Python anonymous code block
+DROP TABLE test1;
diff --git a/src/pl/plpython/plpy_main.c b/src/pl/plpython/plpy_main.c
index 695de30583..254ab37359 100644
--- a/src/pl/plpython/plpy_main.c
+++ b/src/pl/plpython/plpy_main.c
@@ -262,6 +262,9 @@ plpython_call_handler(PG_FUNCTION_ARGS)
                else
                {
                        proc = PLy_procedure_get(funcoid, InvalidOid, false);
+                       if (proc->is_procedure &&
+                               !castNode(CallContext, fcinfo->context)->atomic)
+                                       SPI_set_nonatomic();
                        exec_ctx->curr_proc = proc;
                        retval = PLy_exec_function(fcinfo, proc);
                }
@@ -305,6 +308,8 @@ plpython_inline_handler(PG_FUNCTION_ARGS)
        /* Note: SPI_finish() happens in plpy_exec.c, which is dubious design */
        if (SPI_connect() != SPI_OK_CONNECT)
                elog(ERROR, "SPI_connect failed");
+       if (!codeblock->atomic)
+               SPI_set_nonatomic();
 
        MemSet(&fake_fcinfo, 0, sizeof(fake_fcinfo));
        MemSet(&flinfo, 0, sizeof(flinfo));
@@ -435,7 +440,7 @@ PLy_push_execution_context(void)
        PLyExecutionContext *context;
 
        context = (PLyExecutionContext *)
-               MemoryContextAlloc(TopTransactionContext, 
sizeof(PLyExecutionContext));
+               MemoryContextAlloc(PortalContext, sizeof(PLyExecutionContext));
        context->curr_proc = NULL;
        context->scratch_ctx = NULL;
        context->next = PLy_execution_contexts;
diff --git a/src/pl/plpython/plpy_plpymodule.c 
b/src/pl/plpython/plpy_plpymodule.c
index 23f99e20ca..b9b9e423a7 100644
--- a/src/pl/plpython/plpy_plpymodule.c
+++ b/src/pl/plpython/plpy_plpymodule.c
@@ -6,8 +6,10 @@
 
 #include "postgres.h"
 
+#include "access/xact.h"
 #include "mb/pg_wchar.h"
 #include "utils/builtins.h"
+#include "utils/snapmgr.h"
 
 #include "plpython.h"
 
@@ -41,6 +43,8 @@ static PyObject *PLy_fatal(PyObject *self, PyObject *args, 
PyObject *kw);
 static PyObject *PLy_quote_literal(PyObject *self, PyObject *args);
 static PyObject *PLy_quote_nullable(PyObject *self, PyObject *args);
 static PyObject *PLy_quote_ident(PyObject *self, PyObject *args);
+static PyObject *PLy_commit(PyObject *self, PyObject *args);
+static PyObject *PLy_rollback(PyObject *self, PyObject *args);
 
 
 /* A list of all known exceptions, generated from backend/utils/errcodes.txt */
@@ -95,6 +99,12 @@ static PyMethodDef PLy_methods[] = {
         */
        {"cursor", PLy_cursor, METH_VARARGS, NULL},
 
+       /*
+        * transaction control
+        */
+       {"commit", PLy_commit, METH_NOARGS, NULL},
+       {"rollback", PLy_rollback, METH_NOARGS, NULL},
+
        {NULL, NULL, 0, NULL}
 };
 
@@ -577,3 +587,21 @@ PLy_output(volatile int level, PyObject *self, PyObject 
*args, PyObject *kw)
         */
        Py_RETURN_NONE;
 }
+
+static PyObject *
+PLy_commit(PyObject *self, PyObject *args)
+{
+       SPI_commit();
+       SPI_start_transaction();
+
+       Py_RETURN_NONE;
+}
+
+static PyObject *
+PLy_rollback(PyObject *self, PyObject *args)
+{
+       SPI_rollback();
+       SPI_start_transaction();
+
+       Py_RETURN_NONE;
+}
diff --git a/src/pl/plpython/sql/plpython_transaction.sql 
b/src/pl/plpython/sql/plpython_transaction.sql
new file mode 100644
index 0000000000..0656aa1458
--- /dev/null
+++ b/src/pl/plpython/sql/plpython_transaction.sql
@@ -0,0 +1,87 @@
+CREATE TABLE test1 (a int, b text);
+
+
+CREATE PROCEDURE transaction_test1()
+LANGUAGE plpythonu
+AS $$
+for i in range(0, 10):
+    plpy.execute("INSERT INTO test1 (a) VALUES (%d)" % i)
+    if i % 2 == 0:
+        plpy.commit()
+    else:
+        plpy.rollback()
+$$;
+
+CALL transaction_test1();
+
+SELECT * FROM test1;
+
+
+TRUNCATE test1;
+
+DO
+LANGUAGE plpythonu
+$$
+for i in range(0, 10):
+    plpy.execute("INSERT INTO test1 (a) VALUES (%d)" % i)
+    if i % 2 == 0:
+        plpy.commit()
+    else:
+        plpy.rollback()
+$$;
+
+SELECT * FROM test1;
+
+
+TRUNCATE test1;
+
+-- not allowed in a function
+CREATE FUNCTION transaction_test2() RETURNS int
+LANGUAGE plpythonu
+AS $$
+for i in range(0, 10):
+    plpy.execute("INSERT INTO test1 (a) VALUES (%d)" % i)
+    if i % 2 == 0:
+        plpy.commit()
+    else:
+        plpy.rollback()
+return 1
+$$;
+
+SELECT transaction_test2();
+
+SELECT * FROM test1;
+
+
+-- also not allowed if procedure is called from a function
+CREATE FUNCTION transaction_test3() RETURNS int
+LANGUAGE plpythonu
+AS $$
+plpy.execute("CALL transaction_test1()")
+return 1
+$$;
+
+SELECT transaction_test3();
+
+SELECT * FROM test1;
+
+
+-- DO block inside function
+CREATE FUNCTION transaction_test4() RETURNS int
+LANGUAGE plpythonu
+AS $$
+plpy.execute("DO LANGUAGE plpythonu $x$ plpy.commit() $x$")
+return 1
+$$;
+
+SELECT transaction_test4();
+
+
+-- commit inside subtransaction (prohibited)
+DO LANGUAGE plpythonu $$
+with plpy.subtransaction():
+    plpy.commit()
+$$;
+
+
+DROP TABLE test1;
diff --git a/src/pl/tcl/Makefile b/src/pl/tcl/Makefile
index 6a92a9b6aa..ef61ee596e 100644
--- a/src/pl/tcl/Makefile
+++ b/src/pl/tcl/Makefile
@@ -28,7 +28,7 @@ DATA = pltcl.control pltcl--1.0.sql 
pltcl--unpackaged--1.0.sql \
        pltclu.control pltclu--1.0.sql pltclu--unpackaged--1.0.sql
 
 REGRESS_OPTS = --dbname=$(PL_TESTDB) --load-extension=pltcl
-REGRESS = pltcl_setup pltcl_queries pltcl_call pltcl_start_proc pltcl_subxact 
pltcl_unicode
+REGRESS = pltcl_setup pltcl_queries pltcl_call pltcl_start_proc pltcl_subxact 
pltcl_unicode pltcl_transaction
 
 # Tcl on win32 ships with import libraries only for Microsoft Visual C++,
 # which are not compatible with mingw gcc. Therefore we need to build a
diff --git a/src/pl/tcl/expected/pltcl_transaction.out 
b/src/pl/tcl/expected/pltcl_transaction.out
new file mode 100644
index 0000000000..6ce900027c
--- /dev/null
+++ b/src/pl/tcl/expected/pltcl_transaction.out
@@ -0,0 +1,63 @@
+-- suppress CONTEXT so that function OIDs aren't in output
+\set VERBOSITY terse
+CREATE TABLE test1 (a int, b text);
+CREATE PROCEDURE transaction_test1()
+LANGUAGE pltcl
+AS $$
+for {set i 0} {$i < 10} {incr i} {
+    spi_exec "INSERT INTO test1 (a) VALUES ($i)"
+    if {$i % 2 == 0} {
+        commit
+    } else {
+        rollback
+    }
+}
+$$;
+CALL transaction_test1();
+SELECT * FROM test1;
+ a | b 
+---+---
+ 0 | 
+ 2 | 
+ 4 | 
+ 6 | 
+ 8 | 
+(5 rows)
+
+TRUNCATE test1;
+-- not allowed in a function
+CREATE FUNCTION transaction_test2() RETURNS int
+LANGUAGE pltcl
+AS $$
+for {set i 0} {$i < 10} {incr i} {
+    spi_exec "INSERT INTO test1 (a) VALUES ($i)"
+    if {$i % 2 == 0} {
+        commit
+    } else {
+        rollback
+    }
+}
+return 1
+$$;
+SELECT transaction_test2();
+ERROR:  invalid transaction termination
+SELECT * FROM test1;
+ a | b 
+---+---
+(0 rows)
+
+-- also not allowed if procedure is called from a function
+CREATE FUNCTION transaction_test3() RETURNS int
+LANGUAGE pltcl
+AS $$
+spi_exec "CALL transaction_test1()"
+return 1
+$$;
+SELECT transaction_test3();
+ERROR:  invalid transaction termination
+SELECT * FROM test1;
+ a | b 
+---+---
+(0 rows)
+
+DROP TABLE test1;
diff --git a/src/pl/tcl/pltcl.c b/src/pl/tcl/pltcl.c
index e0792d93e1..0571755b4f 100644
--- a/src/pl/tcl/pltcl.c
+++ b/src/pl/tcl/pltcl.c
@@ -312,6 +312,10 @@ static int pltcl_SPI_lastoid(ClientData cdata, Tcl_Interp 
*interp,
                                  int objc, Tcl_Obj *const objv[]);
 static int pltcl_subtransaction(ClientData cdata, Tcl_Interp *interp,
                                         int objc, Tcl_Obj *const objv[]);
+static int pltcl_commit(ClientData cdata, Tcl_Interp *interp,
+                                        int objc, Tcl_Obj *const objv[]);
+static int pltcl_rollback(ClientData cdata, Tcl_Interp *interp,
+                                        int objc, Tcl_Obj *const objv[]);
 
 static void pltcl_subtrans_begin(MemoryContext oldcontext,
                                         ResourceOwner oldowner);
@@ -524,6 +528,10 @@ pltcl_init_interp(pltcl_interp_desc *interp_desc, Oid 
prolang, bool pltrusted)
                                                 pltcl_SPI_lastoid, NULL, NULL);
        Tcl_CreateObjCommand(interp, "subtransaction",
                                                 pltcl_subtransaction, NULL, 
NULL);
+       Tcl_CreateObjCommand(interp, "commit",
+                                                pltcl_commit, NULL, NULL);
+       Tcl_CreateObjCommand(interp, "rollback",
+                                                pltcl_rollback, NULL, NULL);
 
        /************************************************************
         * Call the appropriate start_proc, if there is one.
@@ -812,6 +820,10 @@ pltcl_func_handler(PG_FUNCTION_ARGS, pltcl_call_state 
*call_state,
        prodesc = compile_pltcl_function(fcinfo->flinfo->fn_oid, InvalidOid,
                                                                         false, 
pltrusted);
 
+       if (prodesc->result_typid == InvalidOid &&
+               !castNode(CallContext, fcinfo->context)->atomic)
+               SPI_set_nonatomic();
+
        call_state->prodesc = prodesc;
        prodesc->fn_refcount++;
 
@@ -2935,6 +2947,38 @@ pltcl_subtransaction(ClientData cdata, Tcl_Interp 
*interp,
 }
 
 
+/**********************************************************************
+ * pltcl_commit()
+ *
+ * Commit the transaction and start a new one.
+ **********************************************************************/
+static int
+pltcl_commit(ClientData cdata, Tcl_Interp *interp,
+                        int objc, Tcl_Obj *const objv[])
+{
+       SPI_commit();
+       SPI_start_transaction();
+
+       return TCL_OK;
+}
+
+
+/**********************************************************************
+ * pltcl_rollback()
+ *
+ * Abort the transaction and start a new one.
+ **********************************************************************/
+static int
+pltcl_rollback(ClientData cdata, Tcl_Interp *interp,
+                          int objc, Tcl_Obj *const objv[])
+{
+       SPI_rollback();
+       SPI_start_transaction();
+
+       return TCL_OK;
+}
+
+
 /**********************************************************************
  * pltcl_set_tuple_values() - Set variables for all attributes
  *                               of a given tuple
diff --git a/src/pl/tcl/sql/pltcl_transaction.sql 
b/src/pl/tcl/sql/pltcl_transaction.sql
new file mode 100644
index 0000000000..14aed5844a
--- /dev/null
+++ b/src/pl/tcl/sql/pltcl_transaction.sql
@@ -0,0 +1,60 @@
+-- suppress CONTEXT so that function OIDs aren't in output
+\set VERBOSITY terse
+
+CREATE TABLE test1 (a int, b text);
+
+
+CREATE PROCEDURE transaction_test1()
+LANGUAGE pltcl
+AS $$
+for {set i 0} {$i < 10} {incr i} {
+    spi_exec "INSERT INTO test1 (a) VALUES ($i)"
+    if {$i % 2 == 0} {
+        commit
+    } else {
+        rollback
+    }
+}
+$$;
+
+CALL transaction_test1();
+
+SELECT * FROM test1;
+
+
+TRUNCATE test1;
+
+-- not allowed in a function
+CREATE FUNCTION transaction_test2() RETURNS int
+LANGUAGE pltcl
+AS $$
+for {set i 0} {$i < 10} {incr i} {
+    spi_exec "INSERT INTO test1 (a) VALUES ($i)"
+    if {$i % 2 == 0} {
+        commit
+    } else {
+        rollback
+    }
+}
+return 1
+$$;
+
+SELECT transaction_test2();
+
+SELECT * FROM test1;
+
+
+-- also not allowed if procedure is called from a function
+CREATE FUNCTION transaction_test3() RETURNS int
+LANGUAGE pltcl
+AS $$
+spi_exec "CALL transaction_test1()"
+return 1
+$$;
+
+SELECT transaction_test3();
+
+SELECT * FROM test1;
+
+
+DROP TABLE test1;
diff --git a/src/test/regress/expected/plpgsql.out 
b/src/test/regress/expected/plpgsql.out
index d6e5bc3353..824977afc5 100644
--- a/src/test/regress/expected/plpgsql.out
+++ b/src/test/regress/expected/plpgsql.out
@@ -6077,7 +6077,248 @@ SELECT * FROM proc_test1;
  55
 (1 row)
 
+TRUNCATE proc_test1;
+CREATE PROCEDURE test_proc_transaction1()
+LANGUAGE plpgsql
+AS $$
+BEGIN
+    FOR i IN 0..9 LOOP
+        INSERT INTO proc_test1 (a) VALUES (i);
+        IF i % 2 = 0 THEN
+            COMMIT;
+        ELSE
+            ROLLBACK;
+        END IF;
+    END LOOP;
+END
+$$;
+CALL test_proc_transaction1();
+SELECT * FROM proc_test1;
+ a 
+---
+ 0
+ 2
+ 4
+ 6
+ 8
+(5 rows)
+
+TRUNCATE proc_test1;
+DO
+LANGUAGE plpgsql
+$$
+BEGIN
+    FOR i IN 0..9 LOOP
+        INSERT INTO proc_test1 (a) VALUES (i);
+        IF i % 2 = 0 THEN
+            COMMIT;
+        ELSE
+            ROLLBACK;
+        END IF;
+    END LOOP;
+END
+$$;
+SELECT * FROM proc_test1;
+ a 
+---
+ 0
+ 2
+ 4
+ 6
+ 8
+(5 rows)
+
+-- transaction commands not allowed when called in transaction block
+START TRANSACTION;
+CALL test_proc_transaction1();
+ERROR:  invalid transaction termination
+CONTEXT:  PL/pgSQL function test_proc_transaction1() line 6 at COMMIT
+COMMIT;
+START TRANSACTION;
+DO LANGUAGE plpgsql $$ BEGIN COMMIT; END $$;
+ERROR:  invalid transaction termination
+CONTEXT:  PL/pgSQL function inline_code_block line 1 at COMMIT
+COMMIT;
+TRUNCATE proc_test1;
+-- not allowed in a function
+CREATE FUNCTION test_proc_transaction2() RETURNS int
+LANGUAGE plpgsql
+AS $$
+BEGIN
+    FOR i IN 0..9 LOOP
+        INSERT INTO proc_test1 (a) VALUES (i);
+        IF i % 2 = 0 THEN
+            COMMIT;
+        ELSE
+            ROLLBACK;
+        END IF;
+    END LOOP;
+    RETURN 1;
+END
+$$;
+SELECT test_proc_transaction2();
+ERROR:  invalid transaction termination
+CONTEXT:  PL/pgSQL function test_proc_transaction2() line 6 at COMMIT
+SELECT * FROM proc_test1;
+ a 
+---
+(0 rows)
+
+-- also not allowed if procedure is called from a function
+CREATE FUNCTION test_proc_transaction3() RETURNS int
+LANGUAGE plpgsql
+AS $$
+BEGIN
+    CALL test_proc_transaction1();
+    RETURN 1;
+END;
+$$;
+SELECT test_proc_transaction3();
+ERROR:  invalid transaction termination
+CONTEXT:  PL/pgSQL function test_proc_transaction1() line 6 at COMMIT
+SQL statement "CALL test_proc_transaction1()"
+PL/pgSQL function test_proc_transaction3() line 3 at SQL statement
+SELECT * FROM proc_test1;
+ a 
+---
+(0 rows)
+
+-- DO block inside function
+CREATE FUNCTION test_proc_transaction4() RETURNS int
+LANGUAGE plpgsql
+AS $$
+BEGIN
+    EXECUTE 'DO LANGUAGE plpgsql $x$ BEGIN COMMIT; END $x$';
+    RETURN 1;
+END;
+$$;
+SELECT test_proc_transaction4();
+ERROR:  invalid transaction termination
+CONTEXT:  PL/pgSQL function inline_code_block line 1 at COMMIT
+SQL statement "DO LANGUAGE plpgsql $x$ BEGIN COMMIT; END $x$"
+PL/pgSQL function test_proc_transaction4() line 3 at EXECUTE
+-- proconfig settings currently disallow transaction statements
+CREATE PROCEDURE test_proc_transaction5()
+LANGUAGE plpgsql
+SET work_mem = 555
+AS $$
+BEGIN
+    COMMIT;
+END;
+$$;
+CALL test_proc_transaction5();
+ERROR:  invalid transaction termination
+CONTEXT:  PL/pgSQL function test_proc_transaction5() line 3 at COMMIT
+-- commit inside cursor loop
+CREATE TABLE proc_test2 (x int);
+INSERT INTO proc_test2 VALUES (0), (1), (2), (3), (4);
+TRUNCATE proc_test1;
+DO LANGUAGE plpgsql $$
+DECLARE
+    r RECORD;
+BEGIN
+    FOR r IN SELECT * FROM proc_test2 ORDER BY x LOOP
+        INSERT INTO proc_test1 (a) VALUES (r.x);
+        COMMIT;
+    END LOOP;
+END;
+$$;
+ERROR:  committing inside a cursor loop is not supported
+CONTEXT:  PL/pgSQL function inline_code_block line 7 at COMMIT
+SELECT * FROM proc_test1;
+ a 
+---
+(0 rows)
+
+-- rollback inside cursor loop
+TRUNCATE proc_test1;
+DO LANGUAGE plpgsql $$
+DECLARE
+    r RECORD;
+BEGIN
+    FOR r IN SELECT * FROM proc_test2 ORDER BY x LOOP
+        INSERT INTO proc_test1 (a) VALUES (r.x);
+        ROLLBACK;
+    END LOOP;
+END;
+$$;
+ERROR:  cannot abort transaction inside a cursor loop
+CONTEXT:  PL/pgSQL function inline_code_block line 7 at ROLLBACK
+SELECT * FROM proc_test1;
+ a 
+---
+(0 rows)
+
+-- commit inside block with exception handler
+TRUNCATE proc_test1;
+DO LANGUAGE plpgsql $$
+BEGIN
+    BEGIN
+        INSERT INTO proc_test1 (a) VALUES (1);
+        COMMIT;
+        INSERT INTO proc_test1 (a) VALUES (1/0);
+        COMMIT;
+    EXCEPTION
+        WHEN division_by_zero THEN
+            RAISE NOTICE 'caught division_by_zero';
+    END;
+END;
+$$;
+ERROR:  cannot commit while a subtransaction is active
+CONTEXT:  PL/pgSQL function inline_code_block line 5 at COMMIT
+SELECT * FROM proc_test1;
+ a 
+---
+(0 rows)
+
+-- rollback inside block with exception handler
+TRUNCATE proc_test1;
+DO LANGUAGE plpgsql $$
+BEGIN
+    BEGIN
+        INSERT INTO proc_test1 (a) VALUES (1);
+        ROLLBACK;
+        INSERT INTO proc_test1 (a) VALUES (1/0);
+        ROLLBACK;
+    EXCEPTION
+        WHEN division_by_zero THEN
+            RAISE NOTICE 'caught division_by_zero';
+    END;
+END;
+$$;
+ERROR:  cannot roll back while a subtransaction is active
+CONTEXT:  PL/pgSQL function inline_code_block line 5 at ROLLBACK
+SELECT * FROM proc_test1;
+ a 
+---
+(0 rows)
+
+-- COMMIT failures
+DO LANGUAGE plpgsql $$
+BEGIN
+    CREATE TABLE proc_test3 (y int UNIQUE DEFERRABLE INITIALLY DEFERRED);
+    COMMIT;
+    INSERT INTO proc_test3 (y) VALUES (1);
+    COMMIT;
+    INSERT INTO proc_test3 (y) VALUES (1);
+    INSERT INTO proc_test3 (y) VALUES (2);
+    COMMIT;
+    INSERT INTO proc_test3 (y) VALUES (3);  -- won't get here
+END;
+$$;
+ERROR:  duplicate key value violates unique constraint "proc_test3_y_key"
+DETAIL:  Key (y)=(1) already exists.
+CONTEXT:  PL/pgSQL function inline_code_block line 9 at COMMIT
+SELECT * FROM proc_test3;
+ y 
+---
+ 1
+(1 row)
+
 DROP PROCEDURE test_proc1;
 DROP PROCEDURE test_proc2;
 DROP PROCEDURE test_proc3;
+DROP PROCEDURE test_proc_transaction1;
 DROP TABLE proc_test1;
+DROP TABLE proc_test2;
+DROP TABLE proc_test3;
diff --git a/src/test/regress/sql/plpgsql.sql b/src/test/regress/sql/plpgsql.sql
index 1c355132b7..3cd61feb70 100644
--- a/src/test/regress/sql/plpgsql.sql
+++ b/src/test/regress/sql/plpgsql.sql
@@ -4864,8 +4864,222 @@ CREATE PROCEDURE test_proc3(x int)
 SELECT * FROM proc_test1;
 
 
+TRUNCATE proc_test1;
+
+CREATE PROCEDURE test_proc_transaction1()
+LANGUAGE plpgsql
+AS $$
+BEGIN
+    FOR i IN 0..9 LOOP
+        INSERT INTO proc_test1 (a) VALUES (i);
+        IF i % 2 = 0 THEN
+            COMMIT;
+        ELSE
+            ROLLBACK;
+        END IF;
+    END LOOP;
+END
+$$;
+
+CALL test_proc_transaction1();
+
+SELECT * FROM proc_test1;
+
+
+TRUNCATE proc_test1;
+
+DO
+LANGUAGE plpgsql
+$$
+BEGIN
+    FOR i IN 0..9 LOOP
+        INSERT INTO proc_test1 (a) VALUES (i);
+        IF i % 2 = 0 THEN
+            COMMIT;
+        ELSE
+            ROLLBACK;
+        END IF;
+    END LOOP;
+END
+$$;
+
+SELECT * FROM proc_test1;
+
+
+-- transaction commands not allowed when called in transaction block
+START TRANSACTION;
+CALL test_proc_transaction1();
+COMMIT;
+
+START TRANSACTION;
+DO LANGUAGE plpgsql $$ BEGIN COMMIT; END $$;
+COMMIT;
+
+
+TRUNCATE proc_test1;
+
+-- not allowed in a function
+CREATE FUNCTION test_proc_transaction2() RETURNS int
+LANGUAGE plpgsql
+AS $$
+BEGIN
+    FOR i IN 0..9 LOOP
+        INSERT INTO proc_test1 (a) VALUES (i);
+        IF i % 2 = 0 THEN
+            COMMIT;
+        ELSE
+            ROLLBACK;
+        END IF;
+    END LOOP;
+    RETURN 1;
+END
+$$;
+
+SELECT test_proc_transaction2();
+
+SELECT * FROM proc_test1;
+
+
+-- also not allowed if procedure is called from a function
+CREATE FUNCTION test_proc_transaction3() RETURNS int
+LANGUAGE plpgsql
+AS $$
+BEGIN
+    CALL test_proc_transaction1();
+    RETURN 1;
+END;
+$$;
+
+SELECT test_proc_transaction3();
+
+SELECT * FROM proc_test1;
+
+
+-- DO block inside function
+CREATE FUNCTION test_proc_transaction4() RETURNS int
+LANGUAGE plpgsql
+AS $$
+BEGIN
+    EXECUTE 'DO LANGUAGE plpgsql $x$ BEGIN COMMIT; END $x$';
+    RETURN 1;
+END;
+$$;
+
+SELECT test_proc_transaction4();
+
+
+-- proconfig settings currently disallow transaction statements
+CREATE PROCEDURE test_proc_transaction5()
+LANGUAGE plpgsql
+SET work_mem = 555
+AS $$
+BEGIN
+    COMMIT;
+END;
+$$;
+
+CALL test_proc_transaction5();
+
+
+-- commit inside cursor loop
+CREATE TABLE proc_test2 (x int);
+INSERT INTO proc_test2 VALUES (0), (1), (2), (3), (4);
+
+TRUNCATE proc_test1;
+
+DO LANGUAGE plpgsql $$
+DECLARE
+    r RECORD;
+BEGIN
+    FOR r IN SELECT * FROM proc_test2 ORDER BY x LOOP
+        INSERT INTO proc_test1 (a) VALUES (r.x);
+        COMMIT;
+    END LOOP;
+END;
+$$;
+
+SELECT * FROM proc_test1;
+
+
+-- rollback inside cursor loop
+TRUNCATE proc_test1;
+
+DO LANGUAGE plpgsql $$
+DECLARE
+    r RECORD;
+BEGIN
+    FOR r IN SELECT * FROM proc_test2 ORDER BY x LOOP
+        INSERT INTO proc_test1 (a) VALUES (r.x);
+        ROLLBACK;
+    END LOOP;
+END;
+$$;
+
+SELECT * FROM proc_test1;
+
+
+-- commit inside block with exception handler
+TRUNCATE proc_test1;
+
+DO LANGUAGE plpgsql $$
+BEGIN
+    BEGIN
+        INSERT INTO proc_test1 (a) VALUES (1);
+        COMMIT;
+        INSERT INTO proc_test1 (a) VALUES (1/0);
+        COMMIT;
+    EXCEPTION
+        WHEN division_by_zero THEN
+            RAISE NOTICE 'caught division_by_zero';
+    END;
+END;
+$$;
+
+SELECT * FROM proc_test1;
+
+
+-- rollback inside block with exception handler
+TRUNCATE proc_test1;
+
+DO LANGUAGE plpgsql $$
+BEGIN
+    BEGIN
+        INSERT INTO proc_test1 (a) VALUES (1);
+        ROLLBACK;
+        INSERT INTO proc_test1 (a) VALUES (1/0);
+        ROLLBACK;
+    EXCEPTION
+        WHEN division_by_zero THEN
+            RAISE NOTICE 'caught division_by_zero';
+    END;
+END;
+$$;
+
+SELECT * FROM proc_test1;
+
+
+-- COMMIT failures
+DO LANGUAGE plpgsql $$
+BEGIN
+    CREATE TABLE proc_test3 (y int UNIQUE DEFERRABLE INITIALLY DEFERRED);
+    COMMIT;
+    INSERT INTO proc_test3 (y) VALUES (1);
+    COMMIT;
+    INSERT INTO proc_test3 (y) VALUES (1);
+    INSERT INTO proc_test3 (y) VALUES (2);
+    COMMIT;
+    INSERT INTO proc_test3 (y) VALUES (3);  -- won't get here
+END;
+$$;
+
+SELECT * FROM proc_test3;
+
+
 DROP PROCEDURE test_proc1;
 DROP PROCEDURE test_proc2;
 DROP PROCEDURE test_proc3;
+DROP PROCEDURE test_proc_transaction1;
 
 DROP TABLE proc_test1;
+DROP TABLE proc_test2;
+DROP TABLE proc_test3;

base-commit: 979a36c3894db0a4b0d6b4b20fc861a0bbe3271c
-- 
2.15.1

Re: [HACKERS] Transaction control in procedures

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