evan/memcached — pull request #108 by juliusv (2012-12-11 14:15:22+00:00)
Title: Saner defaults for retry_timeout and connect_timeout.

With the current defaults for retry_timeout (30s) and connect_timeout
(4s), a single memcached node outage results in bad failover behavior: a
dead server is retried 2 x 4s = 8s before being marked dead, then avoided
for 30s. After 30s, it gets retried again, resulting in the pattern:

8s FAIL - 30s SUCCESS - 8s FAIL - 30s SUCCESS - ...

This translates directly into user-visible site behavior of the same
pattern. With the adjusted defaults in this change, node outages are
dealt with much better:

0.5s FAIL - 60s SUCCESS - 0.5s FAIL - 60s SUCCESS - ...

This results in little to no user-visible site performance degradation.