Memcache Error? “Could not find specified socket in poll list.”

I'm aware this won't quite fix the original issue but hopefully will tell us if the issue is a bug in launchd or something else.

Have you tried removing the cron job and re-instituting it as a proper launchd job instead? launchd is supposed to run the cron jobs but it sounds like you may be running into a bug.

You can create a launchd job using a GUI such as Lingon if you'd prefer instead of making the .plist yourself.

Sample .plist:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>Label</key>
    <string>test.dood.123</string>
    <key>ProgramArguments</key>
    <array>
        <string>cd</string>
        <string>/Library/REMOVED/DIRS/report/</string>
        <string>&amp;&amp;</string>
        <string>nice</string>
        <string>-n</string>
        <string>15</string>
        <string>/usr/local/php5/bin/php</string>
        <string>-f</string>
        <string>report_generator.php</string>
        <string>&gt;</string>
        <string>/dev/null</string>
        <string>2&gt;&amp;1</string>
    </array>
    <key>StartInterval</key>
    <integer>60</integer>
</dict>
</plist>

From my Googling it sounds like it's a bug in launchd running cron jobs. Source: 1

StartInterval will simply run it that many seconds from when the job was last run. StartCalendarInterval will allow you to run it at set times and instead of the <key>StartInterval</key> in the sample above use the following:

Run only at 3:15 AM

 <key>StartCalendarInterval</key>
 <dict>  
     <key>Hour</key>
     <integer>3</integer>
     <key>Minute</key>
     <integer>15</integer>
</dict>

Run every 5 minutes - StartCalendarInterval with an array. (I don't know of a better way to write this out so I'd love someone to elaborate on this)

 <key>StartCalendarInterval</key>
 <array>
     <dict>
         <key>Minute</key>
         <integer>0</integer>
     </dict>
     <dict>
         <key>Minute</key>
         <integer>5</integer>
     </dict>
     <dict>
         <key>Minute</key>
         <integer>10</integer>
     </dict>
     <dict>
         <key>Minute</key>
         <integer>15</integer>
     </dict>
     <dict>
         <key>Minute</key>
         <integer>20</integer>
     </dict>
     <dict>
         <key>Minute</key>
         <integer>25</integer>
     </dict>
     <dict>
         <key>Minute</key>
         <integer>30</integer>
     </dict>
     <dict>
         <key>Minute</key>
         <integer>35</integer>
     </dict>
     <dict>
         <key>Minute</key>
         <integer>40</integer>
     </dict>
     <dict>
         <key>Minute</key>
         <integer>45</integer>
     </dict>
     <dict>
         <key>Minute</key>
         <integer>50</integer>
     </dict>
     <dict>
         <key>Minute</key>
         <integer>55</integer>
     </dict>
 </array>

For more check out the Migrating from cron section on the documentation for launchd and man page

Check your session.gc_maxlifetime setting. Anything bigger than 60*60*24*30 will make memcache expire your session key just after PHP stored it.

Memcache protocol specifies that any number bigger than 60*60*24*30 will be treated as the absolute unix time instead of an offset from the current time:

Some commands involve a client sending some kind of expiration time (relative to an item or to an operation requested by the client) to the server. In all such cases, the actual value sent may either be Unix time (number of seconds since January 1, 1970, as a 32-bit value), or a number of seconds starting from current time. In the latter case, this number of seconds may not exceed 60*60*24*30 (number of seconds in 30 days); if the number sent by a client is larger than that, the server will consider it to be real Unix time value rather than an offset from current time.

(See https://github.com/memcached/memcached/blob/e31a591210311d0658a90a86f71563fa6d7b095c/doc/protocol.txt#L79)

PHP session handler just uses the session.gc_maxlifetime as the expiration time for session key, without doing any changes on it.

Details at: http://rcmachado.github.io/php/memcache/2014/07/23/php-memcached-gotchas.html (disclosure: I wrote the post).