From d15810264161977440df08c9c3a9f60774ad1f0d Mon Sep 17 00:00:00 2001
From: Jared Hancock <jared@osticket.com>
Date: Thu, 23 Oct 2014 13:25:31 -0500
Subject: [PATCH] Rollback to autocommit, except for sequence iteration
Keeping the transaction active for the entire request increases the
likelihood of a deadlock on Galera clusters.
---
include/class.sequence.php | 5 +++++
include/mysqli.php | 19 +++++++------------
2 files changed, 12 insertions(+), 12 deletions(-)
diff --git a/include/class.sequence.php b/include/class.sequence.php
index 1b3fc3182..cc27801c5 100644
--- a/include/class.sequence.php
+++ b/include/class.sequence.php
@@ -151,6 +151,9 @@ class Sequence extends VerySimpleModel {
* and assured to be session-wise atomic before the value is returned.
*/
function __next($digits=false) {
+ // Ensure this block is executed in a single transaction
+ db_autocommit(false);
+
// Lock the database object -- this is important to handle concurrent
// requests for new numbers
static::objects()->filter(array('id'=>$this->id))->lock()->one();
@@ -161,6 +164,8 @@ class Sequence extends VerySimpleModel {
$this->updated = SqlFunction::NOW();
$this->save();
+ db_autocommit(true);
+
return $next;
}
diff --git a/include/mysqli.php b/include/mysqli.php
index 71681975c..ed70cd82e 100644
--- a/include/mysqli.php
+++ b/include/mysqli.php
@@ -76,18 +76,7 @@ function db_connect($host, $user, $passwd, $options = array()) {
@db_set_variable('sql_mode', '');
- // Start a new transaction -- for performance. Transactions are always
- // committed at shutdown (below)
- $__db->autocommit(false);
-
- // Auto commit the transaction at shutdown and re-enable statement-level
- // autocommit
- register_shutdown_function(function() {
- global $__db, $err;
- if (!$__db->commit())
- $err = 'Unable to save changes to database';
- $__db->autocommit(true);
- });
+ $__db->autocommit(true);
// Use connection timing to seed the random number generator
Misc::__rand_seed((microtime(true) - $start) * 1000000);
@@ -95,6 +84,12 @@ function db_connect($host, $user, $passwd, $options = array()) {
return $__db;
}
+function db_autocommit($enable=true) {
+ global $__db;
+
+ return $__db->autocommit($enable);
+}
+
function db_close() {
global $__db;
return @$__db->close();
--
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