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.
pg_get_result
(PHP 4 >= 4.2.0, PHP 5, PHP 7)
pg_get_result — Pobiera wynik zapytania asynchroniczego
Opis
pg_get_result
([ resource
$polaczenie
] ) : resourcepg_get_result() zwraca wynik zapytania asynchronicznego uruchomionego przez pg_send_query(), pg_send_query_params() lub pg_send_execute().
pg_send_query() oraz inne funkcje zapytań asynchronicznych może wysyłać wiele zapytań do serwera PostgreSQL, natomiast pg_get_result() jest używana do pobierania wyników każdego zapytania po kolei.
Parametry
-
polaczenie -
Identyfikator połączenia z bazą PostgreSQL.
Zwracane wartości
Identyfikator wyniku (ang. resource), lub FALSE gdy brak więcej dostępnych wyników.
Przykłady
Przykład #1 pg_get_result() - przykład
<?php
$polaczenie = pg_connect("dbname=wydawca") or die("Nie można się połączyć");
if (!pg_connection_busy($polaczenie)) {
pg_send_query($polaczenie, "select * from autorzy; select count(*) from autorzy;");
}
$wyn1 = pg_get_result($polaczenie);
echo "Pierwsze wywołanie pg_get_result(): $wyn1\n";
$wiersze1 = pg_num_rows($wyn1);
echo "$wyn1 ma $wiersze1 rekordy(ów)\n\n";
$wyn2 = pg_get_result($polaczenie);
echo "Drugie wywołanie pg_get_result(): $wyn2\n";
$wiersze2 = pg_num_rows($wyn2);
echo "$wyn2 ma $wiersze2 rekordy(ów)\n";
?>
Powyższy przykład wyświetli:
Pierwsze wywołanie pg_get_result(): Resource id #3 Resource id #3 ma 3 rekordy(ów) Drugie wywołanie pg_get_result(): Resource id #4 Resource id #4 ma 1 rekordy(ów)
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User Contributed Notes 4 notes
william at 25thandClement dot com ¶
19 years ago
Ondej Bouda ¶
8 years ago
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.
gullevek at gullevek dot org ¶
10 years ago
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);
?>
Marko Tiikkaja ¶
15 years ago
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.
