Why pickle strings?

[askaliuk]

Hello @niwibe ,

IMHO, I found strange django-redis behavior in simple JSON caching.

from django.core.cache import cache
cache.set("123", '{"test":"test"}')

Redis monitor:

~$ redis-cli monitor
OK
1394490905.897550 [1 127.0.0.1:49782] "SETEX" "123" "300" "\x80\x02U\x0f{\"test\":\"test\"}q\x01."

Why does it pickle simple JSON string? Pickled version will take more memory.
Please explain - is it desired behavior?

[niwinz]

Hi @askaliuk

I have used pickle for serialize everything for conserve the real type for everything (django-redis-cache was some bugs related to serialize string, but deserializes integer...)

Now, django-redis deals with integer values as special values and stores it without pickling, allowing
redis atomic operations over it. And... now if I enable string storage without pickling, the previous strange and inconsistent behavior will return (when I set("foo", "1"), get("foo") will return 1 (int))

For more information: https://github.com/niwibe/django-redis/blob/master/redis_cache/client/default.py#L281

If you know any better approach for it, maintaining atomic operations for integers, improvements are welcome.

[niwinz]

As workaround, if you want store raw strings, you can use redis_cache.get_redis_connection(alias) for obtain a raw redis client and use it for store raw strings without serializing.

Also, you can subclass the default client, and overwrite pickle and unpickle methods with own behavior (WARNING: in future release these methods will change to serialize/deserialize ;))

[askaliuk]

Thank you @niwibe for explanation.
I don't have good ideas for now, so feel free to close this issue.

[niwinz]

Thanks to you for your interest! ;)