(PHP 4 >= 4.2.0, PHP 5, PHP 7, PHP 8)
pg_get_result — Lee un resultado asíncrono de PostgreSQL
pg_get_result() recupera la instancia PgSql\Result de una consulta asíncrona ejecutada por pg_send_query(), pg_send_query_params(), o pg_send_execute().
pg_send_query() y otras funciones de consulta asíncrona pueden enviar múltiples consultas a un servidor PostgreSQL y pg_get_result() se utiliza para obtener cada resultado de consulta, uno por uno.
Una instancia de PgSql\Result, o false si no hay más resultados disponibles.
| Versión | Descripción |
|---|---|
| 8.1.0 | Ahora devuelve una instancia de PgSql\Result ; anteriormente, se devolvía un resource. |
| 8.1.0 |
El parámetro connection ahora espera una instancia de
PgSql\Connection ; anteriormente, se esperaba un resource.
|
Ejemplo #1 Ejemplo con pg_get_result()
<?php
$dbconn = pg_connect("dbname=publisher") or die("Conexión imposible");
if (!pg_connection_busy($dbconn)) {
pg_send_query($dbconn, "select * from autores; select count(*) from autores;");
}
$res1 = pg_get_result($dbconn);
echo "Primera llamada a pg_get_result(): $res1\n";
$rows1 = pg_num_rows($res1);
echo "$res1 tiene $rows1 registros\n\n";
$res2 = pg_get_result($dbconn);
echo "Segunda llamada a pg_get_result(): $res2\n";
$rows2 = pg_num_rows($res2);
echo "$res2 tiene $rows2 registros\n";
?>El ejemplo anterior mostrará :
Primera llamada a pg_get_result(): Resource id #3 Resource id #3 tiene 3 registros Segunda llamada a pg_get_result(): Resource id #4 Resource id #4 tiene 1 registros
There is no way to poll/wait for a notification to come in. You either have to enter a busy loop or sleep. Both options are horrible. It would be nice for PHP to provide access to PQsocket so one could select() on the socket connection. This is how it's done from C or Perl.It might seem that after calling pg_get_result() upon sending just a single query, the connection will not be busy. The correct way is, though, to call extra pg_get_result() in a loop until it returns false [1].
<?php
$conn = pg_connect('...', PGSQL_CONNECT_FORCE_NEW);
for ($i = 0; $i < 10000; $i++) {
$query = 'erroneous query';
if (pg_connection_busy($conn)) {
fprintf(STDERR, "Connection is busy\n");
exit(1);
}
pg_send_query($conn, $query);
$res = pg_get_result($conn);
if ($res === false) {
fprintf(STDERR, "A result was expected\n");
exit(1);
}
/* The following does not seem necessary for good queries, but is vital for erroneous queries.
Commenting the loop out leads to this script fail with the "Connection is busy" error. */
while (pg_get_result($conn));
// result processing...
}
?>
See http://www.postgresql.org/message-id/flat/gtitqq$26l3$1@news.hub.org#gtitqq$26l3$1@news.hub.org and https://bugs.php.net/bug.php?id=52750 for detailed information.
[1] Or, even better, use an asynchronous connection since PHP 5.6.To have a a simple wait output with async queries you can use the pg_connection_busy command:
<?php
$dbh = pg_connect("host=XXX user=XXX password=XXX dbname=XXX");
if (!$dbh)
{
print "Failed to connect";
exit;
}
$query = "SELECT pg_sleep(10)";
if (!pg_connection_busy($dbh))
{
$sent = pg_send_query($dbh, $query);
print "Sent query, waiting: ";
while (pg_connection_busy($dbh)
{
print ".";
flush();
}
$res = pg_get_result($dbh);
print "<br>"; // or \n
print "Result is: $res";
}
pg_close($dbh);
?>william at 25thandClement dot com said: "There is no way to poll/wait for a notification to come in. .."
Yes, there is. If there is a query in progress, pg_get_result() will block and return the result of that query when it's complete.