ConFoo 2025

pg_get_result

(PHP 4 >= 4.2.0, PHP 5, PHP 7, PHP 8)

pg_get_result Get asynchronous query result

Açıklama

pg_get_result(PgSql\Connection $connection): PgSql\Result|false

pg_get_result() gets an PgSql\Result instance from an asynchronous query executed by pg_send_query(), pg_send_query_params() or pg_send_execute().

pg_send_query() and the other asynchronous query functions can send multiple queries to a PostgreSQL server and pg_get_result() is used to get each query's results, one by one.

Bağımsız Değişkenler

connection

PostgreSQL veritabanı bağlantısı özkaynağı.

Dönen Değerler

An PgSql\Result instance, or false if no more results are available.

Sürüm Bilgisi

Sürüm: Açıklama
8.1.0 Artık PgSql\Result nesnesi dönüyor; evvelce bir özkaynak dönerdi.
8.1.0 bağlantı bağımsız değişkeni artık PgSql\Connection nesnesi kabul ediyor, evvelce bir özkaynak kabul ederdi.

Örnekler

Örnek 1 pg_get_result() example

<?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";
?>

Yukarıdaki örneğin çıktısı:

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

Ayrıca Bakınız

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User Contributed Notes 4 notes

up
6
william at 25thandClement dot com
19 years ago
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.
up
0
Ondej Bouda
9 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.
up
0
gullevek at gullevek dot org
11 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);
?>
up
-4
Marko Tiikkaja
16 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.
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