(PHP 4 >= 4.2.0, PHP 5, PHP 7, PHP 8)
pg_get_result — Obtém o resultado da consulta assíncrona
pg_get_result() obtém uma instância de PgSql\Result de uma consulta assíncrona executada por pg_send_query(), pg_send_query_params() ou pg_send_execute().
pg_send_query() e outras funções de consulta assíncrona podem enviar múltiplas consultas para um servidor PostgreSQL e pg_get_result() é usado para obter os resultados de cada consulta, um por um.
Uma instância PgSql\Result ou false se não houver mais resultados disponíveis.
| Versão | Descrição |
|---|---|
| 8.1.0 | Agora retorna uma instância de PgSql\Result; anteriormente, um resource era retornado. |
| 8.1.0 |
O parâmetro connection agora espera uma instância de PgSql\Connection;
anteriormente, um resource era esperado.
|
Exemplo #1 Exemplo de pg_get_result()
<?php
$dbconn = pg_connect("dbname=publisher") or die("Não foi possível conectar");
if (!pg_connection_busy($dbconn)) {
pg_send_query($dbconn, "select * from authors; select count(*) from authors;");
}
$res1 = pg_get_result($dbconn);
echo "Primeira chamada para pg_get_result(): $res1\n";
$rows1 = pg_num_rows($res1);
echo "$res1 has $rows1 records\n\n";
$res2 = pg_get_result($dbconn);
echo "Segunda chamada para pg_get_result(): $res2\n";
$rows2 = pg_num_rows($res2);
echo "$res2 has $rows2 records\n";
?>O exemplo acima produzirá:
Primeira chamada para pg_get_result(): Resource id #3 Resource id #3 has 3 records Segunda chamada para pg_get_result(): Resource id #4 Resource id #4 has 1 records
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.