How to flush the Redis cache while using the AWS Elasticache cluster? With our AWS Support Services, Bobcares offers a simple solution to this query.

Flush Redis Cache While Using AWS

Redis is a data structure store that can be used for the purpose of caching. It is open-source and supports data structures like strings, hashes, lists, sets, etc. Redis is a popular distributed caching engine because it is highly available and tuned for speed.

We can flush the cache and delete all keys using any one of the following commands:

• FLUSHDB
• FLUSHALL

The FLUSHDB command removes all the keys of the currently selected DB. And the FLUSHALL command deletes all the keys of all the existing databases, not just the currently selected one.

Syntax For Flushing Redis Cache

The syntax for flushing the Redis cache from the shell prompt is as follows:

redis-cli FLUSHDB
redis-cli -n DB_NUMBER FLUSHDB
redis-cli -n DB_NUMBER FLUSHDB ASYNC
redis-cli FLUSHALL
redis-cli FLUSHALL ASYNC

We can also configure the server’s hostname, port, socket, and password when connecting to the server as given below. We can use the REDISCLI_AUTH environment variable to pass this password more safely.

redis-cli -h {hostname_IP} -p {port} -s {socket} -a {password}  FLUSHDB
redis-cli -h {hostname_IP} -p {port} -s {socket} -a {password} FLUSHALL

How To Flush Redis Cache While Using AWS Elasticache Cluster?

Amazon ElastiCache is an Amazon Web Services completely managed in-memory data storage and cache service.

We must run the FLUSHDB or FLUSHALL command on each master node when utilizing a cluster. For example, using bash for loop, execute the following command on three master nodes:

# three master node ip address
for s in 10.105.29.1 10.105.29.2 10.105.29.3
do
  echo "Flushing DB from $s node ..."
  redis-cli -h $s FLUSHDB
done

No need to reboot the node. We can run the above commands from the EC2 cloud server/host. Or else, we can use API:

# FLUSH everything #
$ redis-cli -h AWS-Elasticache-Host -p AWS-Port_Number
FLUSHALL
# FLUSH by DB_NUMBER aka specific DB #
$ redis-cli -h AWS-Elasticache-Host -p AWS-Port_Number -n 
DB_NUMBER FLUSHDB

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Conclusion

To conclude, the article provides a brief description of the Redis Cache and how to flush it when using the AWS Elasticache cluster.