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, PHP 8)
pg_get_result — 非同期クエリの結果を取得する
説明
pg_get_result(resource
$connection = ?): resourcepg_get_result() は、 pg_send_query()・pg_send_query_params() あるいは pg_send_execute() で実行した非同期クエリから結果リソースを取得します。
pg_send_query() およびその他の非同期クエリ関数は、 複数のクエリを PostgreSQL サーバーに送信することが可能です。クエリの結果を ひとつずつ取得するには、pg_get_result() を使用します。
パラメータ
-
connection -
PostgreSQL データベースの接続リソース。
返り値
結果 resource を返します。結果がもうない場合に false
を返します。
例
例1 pg_get_result() の例
<?php
$dbconn = pg_connect("dbname=publisher") or die("Could not connect");
if (!pg_connection_busy($dbconn)) {
pg_send_query($dbconn, "select * from authors; select count(*) from authors;");
}
$res1 = pg_get_result($dbconn);
echo "First call to pg_get_result(): $res1\n";
$rows1 = pg_num_rows($res1);
echo "$res1 has $rows1 records\n\n";
$res2 = pg_get_result($dbconn);
echo "Second call to pg_get_result(): $res2\n";
$rows2 = pg_num_rows($res2);
echo "$res2 has $rows2 records\n";
?>
上の例の出力は以下となります。
First call to pg_get_result(): Resource id #3 Resource id #3 has 3 records Second call to pg_get_result(): Resource id #4 Resource id #4 has 1 records
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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.
