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($all_links));
NOTE: If you get a "Warning: mysqli::query() expects parameter 2 to be long, string given" you have a mysqlnd installation or configuration issue.
mysqli::poll
mysqli_poll
(PHP 5 >= 5.3.0)
mysqli::poll -- mysqli_poll — Poll connections
Beskrivelse
Object oriented style
public int mysqli::poll
( array
&$read
, array &$error
, array &$reject
, int $sec
[, int $usec
] )Procedural style
int mysqli_poll
( array
&$read
, array &$error
, array &$reject
, int $sec
[, int $usec
] )Advarsel
This function is currently not documented; only its argument list is available.
Poll connections. Available only with mysqlnd. The method can be used as static.
Parametre
-
read -
-
error -
-
reject -
-
sec -
Number of seconds to wait, must be non-negative.
-
usec -
Number of microseconds to wait, must be non-negative.
Returnerings Værdier
Returns number of ready connections in success, FALSE otherwise.
Eksempler
Eksempel #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, $reject, 1)) {
continue;
}
foreach ($links as $link) {
if ($result = $link->reap_async_query()) {
print_r($result->fetch_row());
mysqli_free_result($result);
$processed++;
}
}
} while ($processed < count($all_links));
?>
The above example will output:
Array
(
[0] => test
)
Se også
- mysqli_query() - Performs a query on the database
- mysqli_reap_async_query() - Get result from async query
add a note
User Contributed Notes 4 notes
l_sanczyk at hotmail dot com ¶
9 years ago
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 ?
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);
?>
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);
?>
