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); $socket = [pg_socket($conn)];
$null = [];
$dispatch_ok = pg_send_query($conn, $query);
$still_running = pg_connection_busy($conn);
while($still_running) {
stream_select($socket, $null, $null, $timeout_seconds); $still_running = pg_connection_busy($conn); 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); ?>
