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Neil Conway
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RESET SESSION, plus related new DDL commands. Patch from Marko Kreen,
reviewed by Neil Conway. This patch adds the following DDL command variants: RESET SESSION, RESET TEMP, RESET PLANS, CLOSE ALL, and DEALLOCATE ALL. RESET SESSION is intended for use by connection pool software and the like, in order to reset a client session to something close to its initial state. Note that while most of these command variants can be executed inside a transaction block (but are not transaction-aware!), RESET SESSION cannot. While this is inconsistent, it is intended to catch programmer mistakes: RESET SESSION in an open transaction block is probably unintended.
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‎doc/src/sgml/ref/close.sgml

Lines changed: 19 additions & 7 deletions
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
11
<!--
2-
$PostgreSQL: pgsql/doc/src/sgml/ref/close.sgml,v 1.24 2006/09/16 00:30:17 momjian Exp $
2+
$PostgreSQL: pgsql/doc/src/sgml/ref/close.sgml,v 1.25 2007/04/12 06:53:45 neilc Exp $
33
PostgreSQL documentation
44
-->
55

@@ -25,7 +25,7 @@ PostgreSQL documentation
2525

2626
<refsynopsisdiv>
2727
<synopsis>
28-
CLOSE <replaceable class="PARAMETER">name</replaceable>
28+
CLOSE { <replaceable class="PARAMETER">name</replaceable> | ALL }
2929
</synopsis>
3030
</refsynopsisdiv>
3131

@@ -44,10 +44,10 @@ CLOSE <replaceable class="PARAMETER">name</replaceable>
4444
transaction is terminated by <command>COMMIT</command> or
4545
<command>ROLLBACK</command>. A holdable cursor is implicitly
4646
closed if the transaction that created it aborts via
47-
<command>ROLLBACK</command>. If the creating transaction successfully
48-
commits, the holdable
49-
cursor remains open until an explicit <command>CLOSE</command> is
50-
executed, or the client disconnects.
47+
<command>ROLLBACK</command>. If the creating transaction
48+
successfully commits, the holdable cursor remains open until an
49+
explicit <command>CLOSE</command> is executed, or the client
50+
disconnects.
5151
</para>
5252
</refsect1>
5353

@@ -63,6 +63,16 @@ CLOSE <replaceable class="PARAMETER">name</replaceable>
6363
</para>
6464
</listitem>
6565
</varlistentry>
66+
67+
<varlistentry>
68+
<term><literal>ALL</literal></term>
69+
<listitem>
70+
<para>
71+
Close all open cursors.
72+
</para>
73+
</listitem>
74+
</varlistentry>
75+
6676
</variablelist>
6777
</refsect1>
6878

@@ -98,7 +108,9 @@ CLOSE liahona;
98108
<title>Compatibility</title>
99109

100110
<para>
101-
<command>CLOSE</command> is fully conforming with the SQL standard.
111+
<command>CLOSE</command> is fully conforming with the SQL
112+
standard. <command>CLOSE ALL</> is a <productname>PostgreSQL</>
113+
extension.
102114
</para>
103115
</refsect1>
104116

‎doc/src/sgml/ref/deallocate.sgml

Lines changed: 11 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
11
<!--
2-
$PostgreSQL: pgsql/doc/src/sgml/ref/deallocate.sgml,v 1.9 2006/09/16 00:30:18 momjian Exp $
2+
$PostgreSQL: pgsql/doc/src/sgml/ref/deallocate.sgml,v 1.10 2007/04/12 06:53:46 neilc Exp $
33
PostgreSQL documentation
44
-->
55

@@ -25,7 +25,7 @@ PostgreSQL documentation
2525

2626
<refsynopsisdiv>
2727
<synopsis>
28-
DEALLOCATE [ PREPARE ] <replaceable class="parameter">name</replaceable>
28+
DEALLOCATE [ PREPARE ] { <replaceable class="parameter">name</replaceable> | ALL }
2929
</synopsis>
3030
</refsynopsisdiv>
3131

@@ -65,6 +65,15 @@ DEALLOCATE [ PREPARE ] <replaceable class="parameter">name</replaceable>
6565
</para>
6666
</listitem>
6767
</varlistentry>
68+
69+
<varlistentry>
70+
<term><literal>ALL</literal></term>
71+
<listitem>
72+
<para>
73+
Deallocate all prepared statements.
74+
</para>
75+
</listitem>
76+
</varlistentry>
6877
</variablelist>
6978
</refsect1>
7079

‎doc/src/sgml/ref/reset.sgml

Lines changed: 60 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
11
<!--
2-
$PostgreSQL: pgsql/doc/src/sgml/ref/reset.sgml,v 1.32 2006/09/16 00:30:19 momjian Exp $
2+
$PostgreSQL: pgsql/doc/src/sgml/ref/reset.sgml,v 1.33 2007/04/12 06:53:46 neilc Exp $
33
PostgreSQL documentation
44
-->
55

@@ -22,9 +22,10 @@ PostgreSQL documentation
2222
<synopsis>
2323
RESET <replaceable class="PARAMETER">configuration_parameter</replaceable>
2424
RESET ALL
25+
RESET { PLANS | SESSION | TEMP | TEMPORARY }
2526
</synopsis>
2627
</refsynopsisdiv>
27-
28+
2829
<refsect1>
2930
<title>Description</title>
3031

@@ -41,7 +42,7 @@ SET <replaceable class="parameter">configuration_parameter</replaceable> TO DEFA
4142

4243
<para>
4344
The default value is defined as the value that the parameter would
44-
have had, had no <command>SET</> ever been issued for it in the
45+
have had, if no <command>SET</> ever been issued for it in the
4546
current session. The actual source of this value might be a
4647
compiled-in default, the configuration file, command-line options,
4748
or per-database or per-user default settings. See <xref
@@ -52,6 +53,15 @@ SET <replaceable class="parameter">configuration_parameter</replaceable> TO DEFA
5253
See the <command>SET</> reference page for details on the
5354
transaction behavior of <command>RESET</>.
5455
</para>
56+
57+
<para>
58+
<command>RESET</> can also be used to release internal resources
59+
that are usually released at the end of session. <command>RESET
60+
TEMP</> drops all temporary tables created in the current session.
61+
<command>RESET PLANS</> releases all internally cached plans.
62+
<command>RESET SESSION</> releases all externally visible temporary
63+
resources associated with the current session.
64+
</para>
5565
</refsect1>
5666

5767
<refsect1>
@@ -76,9 +86,56 @@ SET <replaceable class="parameter">configuration_parameter</replaceable> TO DEFA
7686
</para>
7787
</listitem>
7888
</varlistentry>
89+
90+
<varlistentry>
91+
<term><literal>TEMP, TEMPORARY</literal></term>
92+
<listitem>
93+
<para>
94+
Drops all temporary tables created in the current session.
95+
</para>
96+
</listitem>
97+
</varlistentry>
98+
99+
<varlistentry>
100+
<term><literal>PLANS</literal></term>
101+
<listitem>
102+
<para>
103+
Releases all cached query plans.
104+
</para>
105+
</listitem>
106+
</varlistentry>
107+
108+
<varlistentry>
109+
<term><literal>SESSION</literal></term>
110+
<listitem>
111+
<para>
112+
Releases all temporary resources associated with the current
113+
session. This has the same effect as executing the following
114+
command sequence:
115+
<synopsis>
116+
SET SESSION AUTHORIZATION DEFAULT;
117+
RESET ALL;
118+
DEALLOCATE ALL;
119+
CLOSE ALL;
120+
UNLISTEN *;
121+
RESET PLANS;
122+
RESET TEMP;
123+
</synopsis>
124+
</para>
125+
</listitem>
126+
</varlistentry>
127+
79128
</variablelist>
80129
</refsect1>
81130

131+
<refsect1>
132+
<title>Notes</title>
133+
134+
<para>
135+
<command>RESET SESSION</> cannot be executed inside a transaction block.
136+
</para>
137+
</refsect1>
138+
82139
<refsect1>
83140
<title>Examples</title>
84141

‎src/backend/catalog/namespace.c

Lines changed: 21 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -13,7 +13,7 @@
1313
* Portions Copyright (c) 1994, Regents of the University of California
1414
*
1515
* IDENTIFICATION
16-
* $PostgreSQL: pgsql/src/backend/catalog/namespace.c,v 1.93 2007/03/23 19:53:51 tgl Exp $
16+
* $PostgreSQL: pgsql/src/backend/catalog/namespace.c,v 1.94 2007/04/12 06:53:46 neilc Exp $
1717
*
1818
*-------------------------------------------------------------------------
1919
*/
@@ -1940,6 +1940,26 @@ InitTempTableNamespace(void)
19401940
baseSearchPathValid = false; /* need to rebuild list */
19411941
}
19421942

1943+
/*
1944+
* Remove all temp tables from the temporary namespace.
1945+
*/
1946+
void
1947+
ResetTempTableNamespace(void)
1948+
{
1949+
char namespaceName[NAMEDATALEN];
1950+
Oid namespaceId;
1951+
1952+
/* find oid */
1953+
snprintf(namespaceName, sizeof(namespaceName), "pg_temp_%d", MyBackendId);
1954+
namespaceId = GetSysCacheOid(NAMESPACENAME,
1955+
CStringGetDatum(namespaceName),
1956+
0, 0, 0);
1957+
1958+
/* clean if exists */
1959+
if (OidIsValid(namespaceId))
1960+
RemoveTempRelations(namespaceId);
1961+
}
1962+
19431963
/*
19441964
* End-of-transaction cleanup for namespaces.
19451965
*/

‎src/backend/commands/async.c

Lines changed: 2 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
* Portions Copyright (c) 1994, Regents of the University of California
88
*
99
* IDENTIFICATION
10-
* $PostgreSQL: pgsql/src/backend/commands/async.c,v 1.135 2007/01/05 22:19:25 momjian Exp $
10+
* $PostgreSQL: pgsql/src/backend/commands/async.c,v 1.136 2007/04/12 06:53:46 neilc Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -127,7 +127,6 @@ static bool unlistenExitRegistered = false;
127127
bool Trace_notify = false;
128128

129129

130-
static void Async_UnlistenAll(void);
131130
static void Async_UnlistenOnExit(int code, Datum arg);
132131
static void ProcessIncomingNotify(void);
133132
static void NotifyMyFrontEnd(char *relname, int32 listenerPID);
@@ -335,7 +334,7 @@ Async_Unlisten(const char *relname)
335334
*
336335
*--------------------------------------------------------------
337336
*/
338-
static void
337+
void
339338
Async_UnlistenAll(void)
340339
{
341340
Relation lRel;

‎src/backend/commands/portalcmds.c

Lines changed: 9 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -14,7 +14,7 @@
1414
*
1515
*
1616
* IDENTIFICATION
17-
* $PostgreSQL: pgsql/src/backend/commands/portalcmds.c,v 1.62 2007/03/13 00:33:39 tgl Exp $
17+
* $PostgreSQL: pgsql/src/backend/commands/portalcmds.c,v 1.63 2007/04/12 06:53:46 neilc Exp $
1818
*
1919
*-------------------------------------------------------------------------
2020
*/
@@ -236,11 +236,18 @@ PerformPortalClose(const char *name)
236236
{
237237
Portal portal;
238238

239+
/* NULL means CLOSE ALL */
240+
if (name == NULL)
241+
{
242+
PortalHashTableDeleteAll();
243+
return;
244+
}
245+
239246
/*
240247
* Disallow empty-string cursor name (conflicts with protocol-level
241248
* unnamed portal).
242249
*/
243-
if (!name || name[0] == '\0')
250+
if (name[0] == '\0')
244251
ereport(ERROR,
245252
(errcode(ERRCODE_INVALID_CURSOR_NAME),
246253
errmsg("invalid cursor name: must not be empty")));

‎src/backend/commands/prepare.c

Lines changed: 30 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -10,7 +10,7 @@
1010
* Copyright (c) 2002-2007, PostgreSQL Global Development Group
1111
*
1212
* IDENTIFICATION
13-
* $PostgreSQL: pgsql/src/backend/commands/prepare.c,v 1.70 2007/03/13 00:33:39 tgl Exp $
13+
* $PostgreSQL: pgsql/src/backend/commands/prepare.c,v 1.71 2007/04/12 06:53:46 neilc Exp $
1414
*
1515
*-------------------------------------------------------------------------
1616
*/
@@ -575,7 +575,10 @@ FetchPreparedStatementTargetList(PreparedStatement *stmt)
575575
void
576576
DeallocateQuery(DeallocateStmt *stmt)
577577
{
578-
DropPreparedStatement(stmt->name, true);
578+
if (stmt->name)
579+
DropPreparedStatement(stmt->name, true);
580+
else
581+
DropAllPreparedStatements();
579582
}
580583

581584
/*
@@ -601,6 +604,31 @@ DropPreparedStatement(const char *stmt_name, bool showError)
601604
}
602605
}
603606

607+
/*
608+
* Drop all cached statements.
609+
*/
610+
void
611+
DropAllPreparedStatements(void)
612+
{
613+
HASH_SEQ_STATUS seq;
614+
PreparedStatement *entry;
615+
616+
/* nothing cached */
617+
if (!prepared_queries)
618+
return;
619+
620+
/* walk over cache */
621+
hash_seq_init(&seq, prepared_queries);
622+
while ((entry = hash_seq_search(&seq)) != NULL)
623+
{
624+
/* Release the plancache entry */
625+
DropCachedPlan(entry->plansource);
626+
627+
/* Now we can remove the hash table entry */
628+
hash_search(prepared_queries, entry->stmt_name, HASH_REMOVE, NULL);
629+
}
630+
}
631+
604632
/*
605633
* Implements the 'EXPLAIN EXECUTE' utility statement.
606634
*/

‎src/backend/parser/gram.y

Lines changed: 19 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -11,7 +11,7 @@
1111
*
1212
*
1313
* IDENTIFICATION
14-
* $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.587 2007/04/08 00:26:34 momjian Exp $
14+
* $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.588 2007/04/12 06:53:46 neilc Exp $
1515
*
1616
* HISTORY
1717
* AUTHOR DATE MAJOR EVENT
@@ -1667,6 +1667,12 @@ ClosePortalStmt:
16671667
n->portalname = $2;
16681668
$$ = (Node *)n;
16691669
}
1670+
| CLOSE ALL
1671+
{
1672+
ClosePortalStmt *n = makeNode(ClosePortalStmt);
1673+
n->portalname = NULL;
1674+
$$ = (Node *)n;
1675+
}
16701676
;
16711677

16721678

@@ -5591,6 +5597,18 @@ DeallocateStmt: DEALLOCATE name
55915597
n->name = $3;
55925598
$$ = (Node *) n;
55935599
}
5600+
| DEALLOCATE ALL
5601+
{
5602+
DeallocateStmt *n = makeNode(DeallocateStmt);
5603+
n->name = NULL;
5604+
$$ = (Node *) n;
5605+
}
5606+
| DEALLOCATE PREPARE ALL
5607+
{
5608+
DeallocateStmt *n = makeNode(DeallocateStmt);
5609+
n->name = NULL;
5610+
$$ = (Node *) n;
5611+
}
55945612
;
55955613

55965614
/*****************************************************************************

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