Comments on: Cache duration and configuration tips

By: morris

morris — Fri, 03 Apr 2009 20:40:33 +0000

I came across the same “problem”. I don’t know if it is really a problem but it IS making most of my cache writes register as expired.. and it makes using Cache a bit more of a headache.

Seems to be that when you READ a cache file it will check against two values to see if should be expired. First it will compare to the defined expiration… if you set one, ie:

Cache::write(‘filename’, ‘data’, ‘+1 day’);

Then it ALSO checks against the DEFAULT expiration duration + current time. It is 3600 (1 hour) by default.

Strange thing (to me) is that it is checking if cachetime (+1 day) is greater than time + duration (current time + 3600). If it is.. it is considered expired. So, if I write a cache that expires in +1 day.. and try to read that cache within 23 hours, it will be considered expired.

I’m still trying to wrap my head around this but so far a workaround seems to be if you set the default duration for your cache config to something longer than you typically use in your app.. like +1 month. Then, as long as you aren’t caching anything longer than that, it will work as it had previously (and you can just write in the duration as your third param in Cache::write)

By: Taras Kozlov

Taras Kozlov — Thu, 02 Apr 2009 13:15:47 +0000

Charlie,

Thank you again for your help. And you are right that we probably need to finish the conversation here.

By: primeminister

primeminister — Thu, 02 Apr 2009 13:13:21 +0000

File a ticket on trac.cakephp.org. Reference to my ticket and specify this. They will help you

By: Taras Kozlov

Taras Kozlov — Thu, 02 Apr 2009 13:11:44 +0000

Charlie,

You probably won’t believe in this, but according to my tests – cache works fine when defined right in the action, but doesn’t work when defined in the core.php. Moreover, even if you initialize another storage engine right in the action – other ones will work fine.

Btw, I used storage names in the read/write from the beginning.

By: primeminister

primeminister — Thu, 02 Apr 2009 07:38:07 +0000

@Taras: Sorry, my bad. It is working perfectly. I used it wrong. If you use the config name for every read and write action it is wroking fine.
If you are not sure, make a testcase (or change my patch at https://trac.cakephp.org/ticket/6262 )

By: Taras Kozlov

Taras Kozlov — Wed, 01 Apr 2009 21:23:30 +0000

Charlie,

Thank you for your help in clarifying the issue.

By: primeminister

primeminister — Wed, 01 Apr 2009 21:14:15 +0000

Taras: you were right. I made a ticket with a testcase patch: https://trac.cakephp.org/ticket/6262

By: primeminister

primeminister — Wed, 01 Apr 2009 08:50:32 +0000

Interesting Taras… I will dive into that myself. If this is true, it is a bug.

By: Taras Kozlov

Taras Kozlov — Wed, 01 Apr 2009 08:49:17 +0000

When Cache::read calls FileEngine::read actual storage’s settings aren’t passed there (I understand that I probably missed something), but when I added a dump to the FileEngine::read method to show me the actual settings it’s shown data the was defined in the _last_ file storage defined in core.php

So, when it evaluates line #169 (that I explained above) it uses incorrect values.

By: primeminister

primeminister — Wed, 01 Apr 2009 08:39:58 +0000

@Taras: You read and write and set the cache config explicitly. SO how come that the order of the configs in core.php will be of any influence?