From e1a5bb345b1b30ea777348efa9cade21c1f2e2fb Mon Sep 17 00:00:00 2001 From: Andrey Andreev Date: Wed, 4 Mar 2015 13:33:39 +0200 Subject: Fix #3627: Keep timed locks for more than 5 seconds Emulated locks for Redis and Memcached now have a TTL of 300 seconds (the default HTTP request timeout value on many environments) and 30 attemps, each separated by sleep(1), are made by the blocked request to try and obtain a lock if it has been freed. Additionaly, the blocking time for MySQL's locks, which are also timed, is also set to 300 seconds. --- .../Session/drivers/Session_memcached_driver.php | 30 +++++++--------------- 1 file changed, 9 insertions(+), 21 deletions(-) (limited to 'system/libraries/Session/drivers/Session_memcached_driver.php') diff --git a/system/libraries/Session/drivers/Session_memcached_driver.php b/system/libraries/Session/drivers/Session_memcached_driver.php index f1a6e2400..938a612d9 100644 --- a/system/libraries/Session/drivers/Session_memcached_driver.php +++ b/system/libraries/Session/drivers/Session_memcached_driver.php @@ -204,7 +204,7 @@ class CI_Session_memcached_driver extends CI_Session_driver implements SessionHa if (isset($this->_lock_key)) { - $this->_memcached->replace($this->_lock_key, time(), 5); + $this->_memcached->replace($this->_lock_key, time(), 300); if ($this->_fingerprint !== ($fingerprint = md5($session_data))) { if ($this->_memcached->set($this->_key_prefix.$session_id, $session_data, $this->_config['expiration'])) @@ -299,34 +299,21 @@ class CI_Session_memcached_driver extends CI_Session_driver implements SessionHa { if (isset($this->_lock_key)) { - return $this->_memcached->replace($this->_lock_key, time(), 5); + return $this->_memcached->replace($this->_lock_key, time(), 300); } + // 30 attempts to obtain a lock, in case another request already has it $lock_key = $this->_key_prefix.$session_id.':lock'; - if ( ! ($ts = $this->_memcached->get($lock_key))) - { - if ( ! $this->_memcached->set($lock_key, TRUE, 5)) - { - log_message('error', 'Session: Error while trying to obtain lock for '.$this->_key_prefix.$session_id); - return FALSE; - } - - $this->_lock_key = $lock_key; - $this->_lock = TRUE; - return TRUE; - } - - // Another process has the lock, we'll try to wait for it to free itself ... $attempt = 0; - while ($attempt++ < 5) + do { - usleep(((time() - $ts) * 1000000) - 20000); - if (($ts = $this->_memcached->get($lock_key)) < time()) + if ($this->_memcached->get($lock_key)) { + sleep(1); continue; } - if ( ! $this->_memcached->set($lock_key, time(), 5)) + if ( ! $this->_memcached->set($lock_key, time(), 300)) { log_message('error', 'Session: Error while trying to obtain lock for '.$this->_key_prefix.$session_id); return FALSE; @@ -335,8 +322,9 @@ class CI_Session_memcached_driver extends CI_Session_driver implements SessionHa $this->_lock_key = $lock_key; break; } + while ($attempt++ < 30); - if ($attempt === 5) + if ($attempt === 30) { log_message('error', 'Session: Unable to obtain lock for '.$this->_key_prefix.$session_id.' after 5 attempts, aborting.'); return FALSE; -- cgit v1.2.3-24-g4f1b