copy a redis db key to another place (use MIGRATE COPY for v3.0<= redis)

copy_redis_key.sh

#!/bin/bash
# source http://stackoverflow.com/questions/23222616/copy-all-keys-from-one-db-to-another-in-redis
#set connection data accordingly
source_host=localhost
source_port=6379
source_db=1
target_host=localhost
target_port=6379
target_db=2

#copy all keys without preserving ttl!
redis-cli -h $source_host -p $source_port -n $source_db keys \* | while read key;
do
    echo "Copying $key"
    redis-cli --raw -h $source_host -p $source_port -n $source_db DUMP "$key" | head -c -1 | redis-cli -x -h $target_host -p $target_port -n $target_db RESTORE "$key" 0
done

Sorry i'm not using ttl keys for now

`#!/bin/bash

source_host=10.128.0.157
source_port=6393
target_host=prod-experienceservice-elasticache.l15s7f.ng.0001.usw2.cache.amazonaws.com
target_port=6379

function copy_key {
key="$1"
echo "Copying $key"
redis-cli --raw -h $source_host -p $source_port DUMP "$key" | head -c-1 | redis-cli -x -h $target_host -p $target_port RESTORE "$key" 0
if [ $? -ne 0 ]; then
echo "Error copying key $key"
# Handle error as needed
fi
}

export -f copy_key
export source_host
export source_port
export target_host
export target_port

redis-cli -h $source_host -p $source_port keys '*' | xargs -I {} -P 16 bash -c 'copy_key "$@"' _ {}`

This works much better and distributes the load to 16 threads