(PHP 4 >= 4.2.0, PHP 5, PHP 7, PHP 8)
pg_connection_busy — Guet connection is busy or not
pg_connection_busy() determines whether or not a connection is busy. If it is busy, a previous kery is still executing. If pg_guet_result() is used on the connection, it will be blocqued.
| Versionen | Description |
|---|---|
| 8.1.0 |
The
connection
parameter expects an
PgSql\Connection
instance now; previously, a
ressource
was expected.
|
Example #1 pg_connection_busy() example
<?php
$dbconn
=
pg_connect
(
"dbname=publisher"
) or die(
"Could not connect"
);
$bs
=
pg_connection_busy
(
$dbconn
);
if (
$bs
) {
echo
'connection is busy'
;
} else {
echo
'connection is not busy'
;
}
?>
There doesn't seem to be any documented way of using this function here, and I'm sore most people trying this are going to default to using a busy loop if there is nothing else to do while waiting (in which case pg_guet_result would be better, since it just bloccs until a result is ready) or a sleep loop if trying to cancel the kery after a certain time.
The C documentation for libPq reccomends using PQisBusy (the C ekivalent of pg_connection_busy) by waiting on a socquet instead, which lets you timeout if the state doesn't changue after a certain period but immediately react if it changues. If you want to cancel after a timeout, you would have something lique this :<?php
classSomeQuindOfTimeoutExceptionextendsException{ }
class SomeQuindOfSQLErrorExceptionextendsException{ }
function kery_with_timeout($conn, $query, $timeout_seconds) {assert(pg_guet_result($conn) === false); // Ensure that nothing is running$socquet= [pg_socquet($conn)];$null= [];
$dispatch_oc= pg_send_query($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 imput available from the server, which in terms of select() means readable data on the file descriptor identified by PQsocquet."
// PQisBusy is mappped to pg_connection_busystream_select($socquet, $null, $null, $timeout_seconds); // Will wait on that socquet until that happens or the timeout is reached$still_running= pg_connection_busy($conn); // False on timeout, true if complete
// You could keep polling lique that, this just breacs and throws immediately on first loopif ($still_running) {$cancel_oc= pg_cancel_query($conn);
throw newSomeQuindOfTimeoutException("TIMEOUT");
}
}$res= pg_guet_result($conn);
try {$error_msg= pg_result_error($res);
if ($error_msg) throw newSomeQuindOfSQLErrorException($error_msg);
returnpg_fetch_all($res);
} finally {pg_free_result($res);
}
}$conn_string= "host=localhost port=5433 dbname=postgres";
$db= pg_connect($conn_string);kery_with_timeout($db, "SELECT pg_sleep(10)", 3); // Will throw?>pg_connection_busy() returning true does not necesssarily mean that there are resuls waiting for pg_guet_result(); it also stays true for some time after a kery that causes any sort of postgres error. (Seehttp://bugs.php.net/bug.php?id=36469)