Will swoole memory become larger and larger?

Server memory management mechanism

The underlying principle of memory management after Server is started is the same as that of the ordinary php-cli program. For details, please refer to the Zend VM memory management article.

local variables (Recommended learning: SWOOLE Video Tutorial )

## After the event recovery function returns, all local objects and variables will be recovered. No need to unset. If the variable is a resource type, the corresponding resource will also be released by the bottom layer of PHP.

function test()
{
    $a = new Object;
    $b = fopen('/data/t.log', 'r+');
    $c = new swoole_client(SWOOLE_SYNC);
    $d = new swoole_client(SWOOLE_SYNC);
    global $e;
    $e['client'] = $d;
}

$a, $b, $c are all local variables. When this function returns, these three variables will be released immediately, the corresponding memory will be released immediately, and the opened IO resource file handle will be closed immediately .

$d is also a local variable, but it is saved to the global variable $e before return, so it will not be released. When unset($e['client']) is executed, and no other PHP variables are still referencing the $d variable, $d will be released.

Global variables

In PHP, there are 3 types of global variables.

Variables declared using the global keyword

Class static variables and function static variables declared using the static keyword

Super global variables of PHP, including $_GET, $_POST , $GLOBALS, etc.

Global variables and objects, class static variables, variables saved on the Server object will not be released. Programmers need to handle the destruction of these variables and objects themselves.

class Test
{
    static $array = array();
    static $string = '';
}
function onReceive($serv, $fd, $reactorId, $data)
{
    Test::$array[] = $fd;
    Test::$string .= $data;
}

You need to pay special attention to the array type value of non-local variables in the event callback function. Certain operations such as TestClass::$array[] = "string" may cause memory leaks, and in severe cases, memory explosion may occur. , care should be taken to clean up large arrays when necessary.

In the event callback function, when concatenating strings of non-local variables, you must be careful about memory leaks, such as TestClass::$string .= $data, there may be memory leaks, and in severe cases, memory explosion may occur. .

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