Memcached backend: pass parameters to memcache backend

[erny]

The problem:

1. Django instantiates memcache client w/o parameters, i.e. pickleProtocol=0
2. I compress a string to < 512K, binary pickle format
3. I encapsulate it inside a dummy object to prevent getting it converted to unicode
4. I pass it to cache.set
5. django does the set w/o min_compress_len.
6. Then python-memcache.set does (indirectly) o dumps with pickleProtocol=0, which results in a my < 512K to a >1,4M string and is silently discarted as max is 1 MB.

Possible solutions:

• django memcached passes pickleProtocol option to memcached backend client
• django memcached does implement splitting into chunks
• I split it into smaller parts in the dummy objects

[Malcolm Tredinnick]

A CACHE_OPTIONS setting, similar to DATABASE_OPTIONS, might be appropriate here. I can imagine that different settings backends requiring a number of different settings (long-term) and trying to jam them all in a URI gets ugly fast. I wouldn't stand in the way of a new setting here (the options would be CACHE_BACKEND specific, but that's fine when you're fine-tuning backend params).

[otherjacob]

This should be doable, but probably too late to get into 1.3. I'll see if I can come up with a good fix for 1.4

[Jacob]

Milestone 1.4 deleted

[Aymeric Augustin]

Change UI/UX from NULL to False.

[Aymeric Augustin]

Change Easy pickings from NULL to False.

[Aymeric Augustin]

• #19810 proposes using the highest pickle protocol available, which is going to resolve the root cause — pickling with an inefficient protocol.
• The CACHES setting was already split like DATABASES, as suggested by Malcolm in comment 2.

I think there's nothing left in this ticket, closing as a duplicate of #19810 which is more specific and will resolve the problem.