ObjectCache API is out of date. This breaks other plugins

I really think this is a big issue for W3 Object Cache. Any code that uses wp_cache_get and uses the found parameter, is totally hosed, if they are using W3TC with object caching turned on.

I’ve fixed my personal copy of w3tc ObjectCache, and I’ve reduced query usage, page load time, load on my DB, etc.

It’s a very simple update. I went to see if I could contribute my code, but did not see a way to do this.

I think everyone using W3TC would benefit from this fix!!!

I also use the WPML plugin for site translations. This plugin adds quite of bit of queries to the site, and uses the “found” parameter when caching query results in a lot of places.

Unfortunately, anyone using W3TC with object caching, is really being hurt by this bug.

Rich

W3TC still works, in that your site will still function.

The Object cache though does not work for anything that tests the $found parameter to determine an object was actually found in the cache. Any performance gain the object cache offers is lost.

The fix is rather simple.

In lib/W3/ObjectCacheBridge.php

change the get function to (line 27):

function get($id, $group = 'default', $force = false, &$found = null) {
        $cache = $this->_get_engine($group);
        return $cache->get($id, $group, $force, $found);
    }

In lib/W3/ObjectCache.php (line 153). I wanted to minimize code changes, so I avoided trying to rewrite this method…

function get($id, $group = 'default', $force = false, &$found = null) {
        if ($this->_debug) {
            $time_start = w3_microtime();
        }

        $key = $this->_get_cache_key($id, $group);
        $internal = isset($this->cache[$key]);

        if ($internal) {
            $value = $this->cache[$key];
            $found = true;
        } elseif ($this->_caching &&
                  !in_array($group, $this->nonpersistent_groups) &&
                    $this->_check_can_cache_runtime($group)) {
            $cache = $this->_get_cache(null, $group);
            $v = $cache->get($key);
            if (is_array($v) && $v['content'] != null)
            {
                $value = $v['content'];
                $found = true;
            }
            else
                $value = false;
        } else {
            $value = false;
        }

        if ($value === null) {
            $value = false;
        }

        if (is_object($value)) {
            $value = clone( $value );
        }

        $this->cache[$key] = $value;
        $this->cache_total++;

        if ($found){
            $cached = true;
            $this->cache_hits++;
        } else {
            $found = false;
            $cached = false;
            $this->cache_misses++;
        }

        /**
         * Add debug info
         */
        if ($this->_debug) {
            $time = w3_microtime() - $time_start;
            $this->time_total += $time;

            if (!$group) {
                $group = 'default';
            }

            $this->debug_info[] = array(
                'id' => $id,
                'group' => $group,
                'cached' => $cached,
                'internal' => $internal,
                'data_size' => ($value ? strlen(serialize($value)) : ''),
                'time' => $time
            );
        }

        return $value;
    }