PHP 7.0.6 Released

mysqli::poll

mysqli_poll

(PHP 5 >= 5.3.0, PHP 7)

mysqli::poll -- mysqli_pollPoll connections

Description

Object oriented style

public static int mysqli::poll ( array &$read , array &$error , array &$reject , int $sec [, int $usec ] )

Procedural style

int mysqli_poll ( array &$read , array &$error , array &$reject , int $sec [, int $usec ] )

Poll connections. Available only with mysqlnd. The method can be used as static.

Parameters

read

List of connections to check for outstanding results that can be read.

error

List of connections on which an error occured, for example, query failure or lost connection.

reject

List of connections rejected because no asynchronous query has been run on for which the function could poll results.

sec

Number of seconds to wait, must be non-negative.

usec

Number of microseconds to wait, must be non-negative.

Return Values

Returns number of ready connections upon success, FALSE otherwise.

Examples

Example #1 A mysqli_poll() example

<?php
$link1 
mysqli_connect();
$link1->query("SELECT 'test'"MYSQLI_ASYNC);
$all_links = array($link1);
$processed 0;
do {
    
$links $errors $reject = array();
    foreach (
$all_links as $link) {
        
$links[] = $errors[] = $reject[] = $link;
    }
    if (!
mysqli_poll($links$errors$reject1)) {
        continue;
    }
    foreach (
$links as $link) {
        if (
$result $link->reap_async_query()) {
            
print_r($result->fetch_row());
            if (
is_object($result))
                
mysqli_free_result($result);
        } else die(
sprintf("MySQLi Error: %s"mysqli_error($link)));
        
$processed++;
    }
} while (
$processed count($all_links));
?>

The above example will output:

Array
(
    [0] => test
)

See Also

User Contributed Notes

shestero at meta dot ua
3 months ago
Sometime it's not clear what does it mean as connection is "ready" . Does it mean the query completed or just some records ready to read?
Is it possible to use asynchronous (unblocking) and unbuffered SELECT-query? I.e. with both MYSQLI_ASYNC|MYSQLI_USE_RESULT

I want some poll-like code inside my loop that has four case-options:
1. Poll wait time-out is over but no records of result set is ready.
2. One or more records are ready to read (but the query still running).
3. Query is successfully over (completed; no more records).
4. Error.

Is it possible?

As I understood the operation of reading a record from unbuffered query is blocking if there are no ready records at the moment, and there is no functions to get out how much records are ready ?
l_sanczyk at hotmail dot com
1 year ago
You can use the following code to execute, for example, 10 simultaneous queries:

$query = "SELECT `field1`, `field2` FROM `table` WHERE `field1`='something'";

$all_links = array();
for($i=0; $i<10; $i++) {
    $link = mysqli_connect("your.mysql.server.here","your@user","pa$$w0rd",DataBase_Name");
    $link->query($query, MYSQLI_ASYNC);
    $all_links[] = $link;
}

$processed = 0;
do {
    $links = $errors = $reject = array();
    foreach ($all_links as $link) {
        $links[] = $errors[] = $reject[] = $link;
    }
    if (!mysqli_poll($links, $errors, $reject, 1)) {
        continue;
    }
    foreach ($links as $link) {
        if ($result = $link->reap_async_query()) {
            print_r($result->fetch_row());
            if (is_object($result))
                mysqli_free_result($result);
        } else die(sprintf("MySQLi Error: %s", mysqli_error($link)));
        $processed++;
    }
} while ($processed < count($all_links));

NOTE: If you get a "Warning: mysqli::query() expects parameter 2 to be long, string given" you have a mysqlnd installation or configuration issue.
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