Function dumpDatabaseConfig

src/bin/pg_dump/pg_dump.c:3710–3785

* Collect any database-specific or role-and-database-specific SET options * for this database, and append them to outbuf. */

 * for this database, and append them to outbuf.
 */
static void
dumpDatabaseConfig(Archive *AH, PQExpBuffer outbuf,
				   const char *dbname, Oid dboid)
{
	PGconn	   *conn = GetConnection(AH);
	PQExpBuffer buf = createPQExpBuffer();
	PGresult   *res;
	int			count = 1;

	/*
	 * First collect database-specific options.  Pre-8.4 server versions lack
	 * unnest(), so we do this the hard way by querying once per subscript.
	 */
	for (;;)
	{
		if (AH->remoteVersion >= 90000)
			printfPQExpBuffer(buf, "SELECT setconfig[%d] FROM pg_db_role_setting "
							  "WHERE setrole = 0 AND setdatabase = '%u'::oid",
							  count, dboid);
		else
			printfPQExpBuffer(buf, "SELECT datconfig[%d] FROM pg_database WHERE oid = '%u'::oid", count, dboid);

		res = ExecuteSqlQuery(AH, buf->data, PGRES_TUPLES_OK);

		if (PQntuples(res) == 1 &&
			!PQgetisnull(res, 0, 0))
		{
			makeAlterConfigCommand(conn, PQgetvalue(res, 0, 0),
								   "DATABASE", dbname, NULL, NULL,
								   outbuf);
			PQclear(res);
			count++;
		}
		else
		{
			PQclear(res);
			break;
		}
	}

	/* Now look for role-and-database-specific options */
	if (AH->remoteVersion >= 90000)
	{
		/* Here we can assume we have unnest() */
		printfPQExpBuffer(buf, "SELECT rolname, unnest(setconfig) "
						  "FROM pg_db_role_setting s, pg_roles r "
						  "WHERE setrole = r.oid AND setdatabase = '%u'::oid",
						  dboid);

		res = ExecuteSqlQuery(AH, buf->data, PGRES_TUPLES_OK);

		if (PQntuples(res) > 0)
		{
			int			i;

			for (i = 0; i < PQntuples(res); i++)
				makeAlterConfigCommand(conn, PQgetvalue(res, i, 1),
									   "ROLE", PQgetvalue(res, i, 0),