INTRODUCTION:
redis-checker is a tool used to check the data consistency between redis
servers, it's especially useful when you want to check if all servers in a
replication chain has the same data.

USAGE:
1. config.py contains a list of redis servers to be checked, each item in
the list is a string contains server ip address and port;
2. Install pyredis;
3. redis-checker.py accepts an integer parameter to specify how many keys
to check, for example:
  $ ./redis-checker.py 10000
Indicates redis-checker to check 10000 keys.
4. Upon finish, it will print the number of unmatched keys and all unmatched
keys will be printed line by line.

NOTICE:
To avoid giving redis servers too much pressure, modify the 'inteval' parameter
in config.py, which specifies how long in seconds to sleep before trying next
key. It can be a float, e.g. specify inteval=0.001 gives at most 1000 keys per
second.

LIMITATION:
Currently only check keys in the default db(db 0), if you have multiple dbs,
you can modify connect_all() in redis-checker.py to check the specific db.