note 123961 added to function.pg-connection-busy

There doesn't seem to be any documented way of using this function here, and I'm sore most people trying this are going to default to using a busy loop if there is nothing else to do while waiting (in which case pg_get_result would be better, since it just blocks until a result is ready) or a sleep loop if trying to cancel the query after a certain time. The C documentation for libPq reccomends using PQisBusy (the C equivalent of pg_connection_busy) by waiting on a socket instead, which lets you timeout if the state doesn't change after a certain period but immediately react if it changes. If you want to cancel after a timeout, you would have something like this : <?php class SomeKindOfTimeoutException extends Exception { } class SomeKindOfSQLErrorException extends Exception { } function query_with_timeout($conn, $query, $timeout_seconds) { assert(pg_get_result($conn) === false); // Ensure that nothing is running $socket = [pg_socket($conn)]; $null = []; $dispatch_ok = pg_send_query($conn, $query); $still_running = pg_connection_busy($conn); while($still_running) { // https://www.postgresql.org/docs/current/libpq-async.html // "A typical application using these functions will have a main loop that uses select() or poll() to wait for all the conditions that it must respond to." // "One of the conditions will be input available from the server, which in terms of select() means readable data on the file descriptor identified by PQsocket." // PQisBusy is mapped to pg_connection_busy stream_select($socket, $null, $null, $timeout_seconds); // Will wait on that socket until that happens or the timeout is reached $still_running = pg_connection_busy($conn); // False on timeout, true if complete // You could keep polling like that, this just breaks and throws immediately on first loop if ($still_running) { $cancel_ok = pg_cancel_query($conn); throw new SomeKindOfTimeoutException("TIMEOUT"); } } $res = pg_get_result($conn); try { $error_msg = pg_result_error($res); if ($error_msg) throw new SomeKindOfSQLErrorException($error_msg); return pg_fetch_all($res); } finally { pg_free_result($res); } } $conn_string = "host=localhost port=5433 dbname=postgres"; $db = pg_connect($conn_string); query_with_timeout($db, "SELECT pg_sleep(10)", 3); // Will throw ?> ---- Server IP: 208.43.231.9 Probable Submitter: 82.199.157.34 (proxied: 207.96.202.138) ---- Manual Page -- http://php.net/manual/en/function.pg-connection-busy.php Edit -- https://master.php.net/note/edit/123961 Del: integrated -- https://master.php.net/note/delete/123961/integrated Del: useless -- https://master.php.net/note/delete/123961/useless Del: bad code -- https://master.php.net/note/delete/123961/bad+code Del: spam -- https://master.php.net/note/delete/123961/spam Del: non-english -- https://master.php.net/note/delete/123961/non-english Del: in docs -- https://master.php.net/note/delete/123961/in+docs Del: other reasons-- https://master.php.net/note/delete/123961 Reject -- https://master.php.net/note/reject/123961 Search -- https://master.php.net/manage/user-notes.php