PG_RETURN_DATUM(current_query(fcinfo));
}
+/*
+ * Retrieve async notifications for a connection.
+ *
+ * Returns an setof record of notifications, or an empty set if none recieved.
+ * Can optionally take a named connection as parameter, but uses the unnamed connection per default.
+ *
+ */
+#define DBLINK_NOTIFY_COLS 3
+
+PG_FUNCTION_INFO_V1(dblink_get_notify);
+Datum
+dblink_get_notify(PG_FUNCTION_ARGS)
+{
+ PGconn *conn = NULL;
+ remoteConn *rconn = NULL;
+ PGnotify *notify;
+ ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+ TupleDesc tupdesc;
+ Tuplestorestate *tupstore;
+ MemoryContext per_query_ctx;
+ MemoryContext oldcontext;
+
+ DBLINK_INIT;
+ if (PG_NARGS() == 1)
+ DBLINK_GET_NAMED_CONN;
+ else
+ conn = pconn->conn;
+
+ /* create the tuplestore */
+ per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
+ oldcontext = MemoryContextSwitchTo(per_query_ctx);
+
+ tupdesc = CreateTemplateTupleDesc(DBLINK_NOTIFY_COLS, false);
+ TupleDescInitEntry(tupdesc, (AttrNumber) 1, "notify_name",
+ TEXTOID, -1, 0);
+ TupleDescInitEntry(tupdesc, (AttrNumber) 2, "be_pid",
+ INT4OID, -1, 0);
+ TupleDescInitEntry(tupdesc, (AttrNumber) 3, "extra",
+ TEXTOID, -1, 0);
+
+ tupstore = tuplestore_begin_heap(true, false, work_mem);
+ rsinfo->returnMode = SFRM_Materialize;
+ rsinfo->setResult = tupstore;
+ rsinfo->setDesc = tupdesc;
+
+ MemoryContextSwitchTo(oldcontext);
+
+ PQconsumeInput(conn);
+ while ((notify = PQnotifies(conn)) != NULL)
+ {
+ Datum values[DBLINK_NOTIFY_COLS];
+ bool nulls[DBLINK_NOTIFY_COLS];
+
+ memset(values, 0, sizeof(values));
+ memset(nulls, 0, sizeof(nulls));
+
+ if (notify->relname != NULL)
+ values[0] = CStringGetTextDatum(notify->relname);
+ else
+ nulls[0] = true;
+
+ values[1] = Int32GetDatum(notify->be_pid);
+
+ if (notify->extra != NULL)
+ values[2] = CStringGetTextDatum(notify->extra);
+ else
+ nulls[2] = true;
+
+ /* switch to appropriate context while storing the tuple */
+ MemoryContextSwitchTo(per_query_ctx);
+ tuplestore_putvalues(tupstore, tupdesc, values, nulls);
+ MemoryContextSwitchTo(oldcontext);
+
+ PQfreemem(notify);
+ PQconsumeInput(conn);
+ }
+
+ /* clean up and return the tuplestore */
+ tuplestore_donestoring(tupstore);
+
+ return (Datum) 0;
+}
+
/*************************************************************
* internal functions
*/
extern Datum dblink_build_sql_delete(PG_FUNCTION_ARGS);
extern Datum dblink_build_sql_update(PG_FUNCTION_ARGS);
extern Datum dblink_current_query(PG_FUNCTION_ARGS);
+extern Datum dblink_get_notify(PG_FUNCTION_ARGS);
#endif /* DBLINK_H */
RETURNS text
AS 'MODULE_PATHNAME', 'dblink_error_message'
LANGUAGE C STRICT;
+
+CREATE OR REPLACE FUNCTION dblink_get_notify(
+ OUT notify_name TEXT,
+ OUT be_pid INT4,
+ OUT extra TEXT
+)
+RETURNS setof record
+AS 'MODULE_PATHNAME', 'dblink_get_notify'
+LANGUAGE C STRICT;
+
+CREATE OR REPLACE FUNCTION dblink_get_notify(
+ conname TEXT,
+ OUT notify_name TEXT,
+ OUT be_pid INT4,
+ OUT extra TEXT
+)
+RETURNS setof record
+AS 'MODULE_PATHNAME', 'dblink_get_notify'
+LANGUAGE C STRICT;
DROP USER MAPPING FOR public SERVER fdtest;
DROP SERVER fdtest;
DROP FOREIGN DATA WRAPPER postgresql;
+-- test asynchronous notifications
+SELECT dblink_connect('dbname=contrib_regression');
+ dblink_connect
+----------------
+ OK
+(1 row)
+
+--should return listen
+SELECT dblink_exec('LISTEN regression');
+ dblink_exec
+-------------
+ LISTEN
+(1 row)
+
+--should return listen
+SELECT dblink_exec('LISTEN foobar');
+ dblink_exec
+-------------
+ LISTEN
+(1 row)
+
+SELECT dblink_exec('NOTIFY regression');
+ dblink_exec
+-------------
+ NOTIFY
+(1 row)
+
+SELECT dblink_exec('NOTIFY foobar');
+ dblink_exec
+-------------
+ NOTIFY
+(1 row)
+
+SELECT notify_name, be_pid = (select t.be_pid from dblink('select pg_backend_pid()') as t(be_pid int)) AS is_self_notify, extra from dblink_get_notify();
+ notify_name | is_self_notify | extra
+-------------+----------------+-------
+ regression | t |
+ foobar | t |
+(2 rows)
+
+SELECT * from dblink_get_notify();
+ notify_name | be_pid | extra
+-------------+--------+-------
+(0 rows)
+
+SELECT dblink_disconnect();
+ dblink_disconnect
+-------------------
+ OK
+(1 row)
+
DROP USER MAPPING FOR public SERVER fdtest;
DROP SERVER fdtest;
DROP FOREIGN DATA WRAPPER postgresql;
+
+-- test asynchronous notifications
+SELECT dblink_connect('dbname=contrib_regression');
+
+--should return listen
+SELECT dblink_exec('LISTEN regression');
+--should return listen
+SELECT dblink_exec('LISTEN foobar');
+
+SELECT dblink_exec('NOTIFY regression');
+SELECT dblink_exec('NOTIFY foobar');
+
+SELECT notify_name, be_pid = (select t.be_pid from dblink('select pg_backend_pid()') as t(be_pid int)) AS is_self_notify, extra from dblink_get_notify();
+
+SELECT * from dblink_get_notify();
+
+SELECT dblink_disconnect();
DROP FUNCTION dblink_is_busy(text);
DROP FUNCTION dblink_send_query(text, text);
+
+DROP FUNCTION dblink_get_notify();
+
+DROP FUNCTION dblink_get_notify(text);
</refsect1>
</refentry>
+ <refentry id="CONTRIB-DBLINK-GET-NOTIFY">
+ <refnamediv>
+ <refname>dblink_get_notify</refname>
+ <refpurpose>retrieve async notifications on a connection</refpurpose>
+ </refnamediv>
+
+ <refsynopsisdiv>
+ <synopsis>
+ dblink_get_notify() returns setof (notify_name text, be_pid int, extra text)
+ dblink_get_notify(text connname) returns setof (notify_name text, be_pid int, extra text)
+ </synopsis>
+ </refsynopsisdiv>
+
+ <refsect1>
+ <title>Description</title>
+
+ <para>
+ <function>dblink_get_notify</> retrieves notifications on either
+ the unnamed connection, or on a named connection if specified.
+ To receive notifications via dblink, <function>LISTEN</> must
+ first be issued, using <function>dblink_exec</>.
+ For details see <xref linkend="sql-listen"> and <xref linkend="sql-notify">.
+ </para>
+
+ </refsect1>
+
+ <refsect1>
+ <title>Arguments</title>
+
+ <variablelist>
+ <varlistentry>
+ <term><parameter>conname</parameter></term>
+ <listitem>
+ <para>
+ The name of a named connection to get notifications on.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>Return Value</title>
+ <para>Returns setof (notify_name text, be_pid int, extra text), or an empty set if none.</para>
+ </refsect1>
+
+ <refsect1>
+ <title>Example</title>
+
+ <programlisting>
+test=# SELECT dblink_exec('LISTEN virtual');
+ dblink_exec
+-------------
+ LISTEN
+(1 row)
+
+test=# SELECT * FROM dblink_get_notify();
+ notify_name | be_pid | extra
+-------------+--------+-------
+(0 rows)
+
+test=# NOTIFY virtual;
+NOTIFY
+
+SELECT * FROM dblink_get_notify();
+ notify_name | be_pid | extra
+-------------+--------+-------
+ virtual | 1229 |
+(1 row)
+ </programlisting>
+ </refsect1>
+ </refentry>
+
<refentry id="CONTRIB-DBLINK-GET-RESULT">
<refmeta>
<refentrytitle>dblink_get_result</refentrytitle>
projects / users / simon / postgres.git / commitdiff