mysqli::poll

mysqli_poll

(PHP 5 >= 5.3.0, PHP 7, PHP 8)

mysqli::poll -- mysqli_pollVérifie l'état de la connexion

Description

Style orienté objet

public static mysqli::poll(
    ?array &$read,
    ?array &$error,
    array &$reject,
    int $seconds,
    int $microseconds = 0
): int|false

Style procédural

mysqli_poll(
    ?array &$read,
    ?array &$error,
    array &$reject,
    int $seconds,
    int $microseconds = 0
): int|false

Vérifie l'état de la connexion. La méthode peut être utilisée comme statique.

Note:

Disponible uniquement avec mysqlnd.

Liste de paramètres

read

Liste des connexions à vérifier pour les résultats exceptionnels qui peuvent être lus.

error

Liste des connexions sur lesquelles une erreur est survenue, par exemple, des échecs de requêtes, ou des pertes de connexion.

reject

Liste des connexions rejetées car des requêtes non-asynchrones y ont été exécutées et pour lesquelles la fonction pourrait sortir des résultats.

seconds

Nombre de secondes d'attente maximale, doit être positif.

microseconds

Nombre de micro-secondes d'attente maximale, doit être positif.

Valeurs de retour

Retourne le nombre de connexions disponibles en cas de succès, false sinon.

Erreurs / Exceptions

Une ValueError est lancée lorsque ni l'argument read ni l'argument error ne sont transmis.

Historique

Version Description
8.3.0 Lance désormais une exception ValueError lorsque ni l'argument read ni l'argument error ne sont transmis.

Exemples

Exemple #1 Exemple avec mysqli_poll()

<?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, $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("Erreur MySQLi : %s", mysqli_error($link)));
$processed++;
}
} while (
$processed < count($all_links));
?>

L'exemple ci-dessus va afficher :

Array
(
    [0] => test
)

Voir aussi

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User Contributed Notes 4 notes

up
6
l_sanczyk at hotmail dot com
9 years 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.
up
4
shestero at meta dot ua
8 years 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 ?
up
0
ekalashnikov at gmail dot com
6 years ago
Improved version of using polling to check for slow query,
"KILL #ID" does not work if id of the myqsli link is the same as the one that kills it,
so you have to disconnect from mysqli and connect again with new link to
kill the #ID.
<?php
// Slow SQL Query
     
$SelectSql = 'SELECT * FROM SLOW_QUERY';
     
$link = mysqli_connect('localhost','user','pass','database');
     
mysqli_query($SelectSql, MYSQLI_ASYNC);
     
$thread_id = mysqli_thread_id($link);
     
// Ignore user abort so we can kill the query
     
ignore_user_abort(true);
     
$MaxTime = 5; // seconds
     
$Overtime = false;
     
$StartTime = time();
      do
      {
         
// Poll MySQL
       
$links = $errors = $reject = array($link);
       
$poll = mysqli_poll($links, $errors, $reject, 0, 500000);
        
// Check if the connection is aborted and the query was killed
       
if (connection_aborted()) {
         
$link_new = mysqli_connect('localhost','user','pass','database');
         
mysqli_kill($link_new, $thread_id);
         
$kill = mysqli_kill($link_new, $thread_id);
          if (
$kill)
          {
            die();
          }
        }
       
$EndTime = time();
       
// Check overtime, kill if detected overtime
       
if ($EndTime - $StartTime > $MaxTime)
        {
         
$link_new = mysqli_connect('localhost','user','pass','database');
         
mysqli_kill($link_new, $thread_id);
         
$Overtime = true;
          echo
'Error: Query took over '.$Overtime.'.';
        }
      } while (!
$poll && $Overtime == false);
?>
up
-1
ekalashnikov at gmail dot com
6 years ago
This is how you can test and terminate slow query with polling.

<?php
// Slow SQL Query
     
$SelectSql = 'SELECT * FROM SLOW_QUERY';
     
$link = mysqli_connect('localhost','user','pass','database');
     
mysqli_query($SelectSql, MYSQLI_ASYNC);
     
$thread_id = mysqli_thread_id($link);
     
// Ignore user abort so we can kill the query
     
ignore_user_abort(true);
     
$MaxTime = 5; // seconds
     
$Overtime = false;
     
$StartTime = time();
      do
      {
         
// Poll MySQL
       
$links = $errors = $reject = array($link);
       
$poll = mysqli_poll($links, $errors, $reject, 0, 500000);
        
// Check if the connection is aborted and the query was killed
       
if (connection_aborted() && mysqli_kill($link, $thread_id)) {
            die();
        }
       
$EndTime = time();
       
// Check overtime, kill if detected overtime
       
if ($EndTime - $StartTime > $MaxTime)
        {
         
mysqli_kill($link, $thread_id);
         
$Overtime = true;
          echo
'Error: Query took over '.$Overtime.'.';
        }
      } while (!
$poll && $Overtime == false);
?>
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