Batch Rename Keys - redis

Question

I have a rather large database (5 dbs of about a million keys each), and each key has the environment namespace in it. For example: "datamine::production::crosswalk==foobar"
I need to sync my development environment with this data copied from the production RDB snapshot.
So what I'm trying to do is batch rename every key, changing the namespace from datamine::production to datamine::development. Is there a good, way to achieve this?
What I've tried so far
redis-cli command of keys "datamine::production*", piped into sed, then back to redis-cli. This takes forever, and bombs for some reason on many keys (combining several in the same line, sporadically). I'd prefer a better option.
Perl search/replace on the .rdb file. My local redis-server flat refuses to load the modified RDB.

Answer 1

The solution:
Ok, here's the script I wrote to solve this problem. It requires the "Redis" gem. Hopefully someone else finds this useful...
#!/usr/bin/env ruby
# A script to translate the current redis database into a namespace for another environment
# GWI's Redis keys are namespaced as "datamine::production", "datamine::development", etc.
# This script connects to redis and translates these key names in-place.
#
# This script does not use Rails, but needs the "redis" gem available
require 'Benchmark'
require 'Redis'
FROM_NAMESPACE = "production"
TO_NAMESPACE = "development"
NAMESPACE_PREFIX = "datamine::"
REDIS_SERVER = "localhost"
REDIS_PORT = "6379"
REDIS_DBS = [0,1,2,3,4,5]
redis = Redis.new(host: REDIS_SERVER, port: REDIS_PORT, timeout: 30)
REDIS_DBS.each do |redis_db|
redis.select(redis_db)
puts "Translating db ##{redis_db}..."
seconds = Benchmark.realtime do
dbsize = redis.dbsize.to_f
inc_threshold = (dbsize/100.0).round
i = 0
old_keys = redis.keys("#{NAMESPACE_PREFIX}#{FROM_NAMESPACE}*")
old_keys.each do |old_key|
new_key = old_key.gsub(FROM_NAMESPACE, TO_NAMESPACE)
redis.rename(old_key, new_key)
print "#{((i/dbsize)*100.0).round}% complete\r" if (i % inc_threshold == 0) # on whole # % only
i += 1
end
end
puts "\nDone. It took #{seconds} seconds"
end

Answer 2

I have a working solution:
EVAL "local old_prefix_len = string.len(ARGV[1])
local keys = redis.call('keys', ARGV[1] .. '*')
for i = 1, #keys do
local old_key = keys[i]
local new_key = ARGV[2] .. string.sub(old_key, old_prefix_len + 1)
redis.call('rename', old_key, new_key)
end" 0 "datamine::production::" "datamine::development::"
Two last parameters are respectively an old prefix and a new prefix.