pg_connect_poll

(PHP 5 >= 5.6.0, PHP 7, PHP 8)

pg_connect_poll — 正在进行尝试轮询 PostgreSQL 链接状态。

说明

pg_connect_poll(resource $connection = ?): int

pg_connect_poll() 轮询使用 pg_connect() 创建的 PostgreSQL 链接状态，根据 PGSQL_CONNECT_ASYNC 选项

参数

connection: PostgreSQL 数据库链接资源

返回值

返回常量 PGSQL_POLLING_FAILED, PGSQL_POLLING_READING, PGSQL_POLLING_WRITING, PGSQL_POLLING_OK, 或者 PGSQL_POLLING_ACTIVE.

add a note

User Contributed Notes 1 note

down

VLroyrenn ¶

3 years ago


So the documentation on this function is pretty barebones (as is the case for a lot of thin PHP wrappers around C functions), but from what I've gathered by reading the libpq doc and trying various things, you should probably know the following :

* Polling the connection while the underlying socket is busy will cause the connection (or at least the polling, I'm not sure) to fail.
* As stated by the libpq documentation, "do not assume that the socket remains the same across PQconnectPoll calls"
* The socket will become ready after every change in connection status, so the connection must be polled multiple times until the function returns "polling_ok" or "polling_failed".
* "polling_active" can never be returned by libpq and has literally never been used anywhere ever, it has been an unused constant since day 1.

What you need to do is use pg_socket get a PHP stream object corresponding to the current socket and wait after it before polling, like so:

<?php
function pg_wait_connection_ready($conn) {
    assert(is_resource($conn));
    assert(get_resource_type($conn) === "pgsql link" || get_resource_type($conn) === "pgsql link persistent");

    // "On the first iteration, i.e. if you have yet to call PQconnectPoll, behave as if it last returned PGRES_POLLING_WRITING."
    $poll_outcome = PGSQL_POLLING_WRITING;

    while (true) {
        $socket = [pg_socket($conn)]; // "Caution: do not assume that the socket remains the same across PQconnectPoll calls."
        $null = [];

        if ($poll_outcome === PGSQL_POLLING_READING) {
            stream_select($socket, $null, $null, 5);
            $poll_outcome = pg_connect_poll($conn);
        } else if ($poll_outcome === PGSQL_POLLING_WRITING) {
            stream_select($null, $socket, $null, 5);
            $poll_outcome = pg_connect_poll($conn);
        } else {
            break;
        }
    }
}

$db = pg_connect($conn_string, PGSQL_CONNECT_ASYNC);
// Do things while the connection is getting ready
pg_wait_connection_ready($db);
pg_query($sql);
?>

add a note

官方地址：https://www.php.net/manual/en/function.pg-connect-poll.php

有任何技术问题请点击这里网站运营推广招聘

IT PHP 编程语言 Linux 开发编程科技 Elasticsearch HTML/CSS/XML 网络 JAVA NoSQL 数据库面试 C/C++ Golang Git 算法操作系统正则表达式 Redis 互联网 MySql JavaScript 运维软件国际架构设计 Mac OS TCP/IP Excel Vim Windows Socket Oracle VR MongoDB Python 运营 MemCache 商业硬件电子娱乐设计 nginx 摄影游戏 WordPress HTTP 团建数码电器

php7 安装fileinfo扩展 preg_split — 通过一个正则表达式分隔字符串 php位值,解决 PHP 中 usort 在值相同时改变原始位置的问题 [PHP] inet_pton/inet_ntop IP地址转换函数 array_multisort() 多字段排序 PHPMailer设置utf8 PHPMailer字符集CharSet ADORecordSet对象 adodb手册 PHP 8.1 [鸟哥]PHP_INT_MIN 和 -9223372036854775808 opcache预加载 Composer的Packagist资源 mysql面试题 [鸟哥]PHP FFI详解 - 一种全新的PHP扩展方式 PHP7添加redis扩展 PHP mkdir()写出来的权限与mode值不符合 Packagist / Composer 中国全量镜像 php中几种注释规范利用php soap实现web service PHP获取指定函数定义在哪个文件中及行号

略微加速

PHP官方手册 - 互联网笔记

pg_connect_poll

说明

参数

返回值

User Contributed Notes 1 note