Why Use Redis instead of MongoDb for Caching?
I've seen many people using Redis as a cache lately, why not Mongo?  As far as I could tell Redis can set an expire date on an index, like memcache but otherwise are there any reasons not to use Mongo for this?

I ask as I'm doing a large join in MySQL and then changing the data after selecting it.  I'm already using memcache on other parts of the site but saving this in Mongo would allow me to do geospatial searches on the cached data.


Why Use Redis instead of MongoDb for Caching?
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I've seen many people using Redis as a cache lately, why not Mongo?  As far as I could tell Redis can set an expire date on an index, like memcache but otherwise are there any reasons not to use Mongo for this?

I ask as I'm doing a large join in MySQL and then changing the data after selecting it.  I'm already using memcache on other parts of the site but saving this in Mongo would allow me to do geospatial searches on the cached data.

