In this reddit blog post, the author talks about MD5ing the cache keys and hence the reason why they find it very difficult to scale out.
Can someone tell me why one would want to md5 cache keys? I didn’t understand the reason even though they explained it as
“A few years ago, we decided to md5
all of our cache keys. We did this
because at the time memcached (which
is what memcachedb is based on) could
only take keys of a certain length. In
fact, the version it is based on still
has this limitation. MD5ing the keys
was a good solution to this problem,
so we thought.”
The key size back then was probably shorter than it is now (currently 250 bytes – and 250 bytes is a pretty huge key name) meaning a sensible key naming convention may not have been possible, so they just used the sensible naming convention and md5’d it.