CascadiaPHP 2024

pg_get_result

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

pg_get_result 取得异步查询结果

说明

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

pg_get_result() 从由 pg_send_query()pg_send_query_params()pg_send_execute() 执行的异步查询中获取 PgSql\Result 实例。

pg_send_query() 和其它异步查询函数可以向 PostgreSQL 服务器发送多个查询,而 pg_get_result() 则用来逐个获取查询结果。

参数

connection

PgSql\Connection 实例。

返回值

PgSql\Result 实例,或者没有更多查询结果,则返回 false

更新日志

版本 说明
8.1.0 现在返回 PgSql\Result 实例,之前返回 resource
8.1.0 现在 connection 参数接受 PgSql\Connection 实例,之前接受 resource

示例

示例 #1 pg_get_result() 示例

<?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";
?>

以上示例会输出:

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

参见

add a note

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
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.
up
0
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);
?>
up
-4
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.
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