Redis - Delete Keys

Sometimes, we need to delete all keys in all databases. This tutorial talks about how to delete keys in the Redis server database. It includes the following items.

• Delete everything in all databases in Redis Server
• Delete all keys in a current database?
• How to empty a redis database?

How to delete all keys in all database?

There are two commands used with the redis-cli command-line utility.

• FLUSHDB:

Delete all keys from the current connection database.

Syntax

FLUSHDB [Mode]

MODE is a modifier for flushing the database. ASYNC | SYNC. ASYNC: Deleting keys with asynchronous. It was added since Redis 4.0.0 version SYNC: Delete keys synchronously, Added since Redis 6.0.0 version

Here is an example to run with the redis-cli command

A:\Java\Redis>redis-cli flushdb
OK

The below command runs in CLI mode.

A:\Java\Redis>redis-cli
127.0.0.1:6379> flushdb
OK

• FLUSHALL

Delete everything including all keys from all databases in a server. It means wiping out entire data on the server.

Syntax

FLUSHALL [Mode]

MODE is a modifier for flushing all databases in a server. Values are ASYNC | SYNC. ASYNC: Deleting keys with asynchronous. It was added since Redis 4.0.0 version SYNC: Delete keys synchronously, Added since Redis 6.0.0 version

Here is an example to run with the redis-cli command

A:\Java\Redis>redis-cli flushall
OK

The below command runs in CLI mode.

A:\Java\Redis>redis-cli
127.0.0.1:6379> flushall
OK

Here is a complete example

• List all keys in the database using the keys * command, Initially empty list.
• Also, the Database is empty
• Next add, two keys - id and name
• list the keys using the keys command
• Run, flushdb command, removes all keys in the current database
• Run, the keys command and show an empty list

Here is a sequence of steps

127.0.0.1:6379> keys *
(empty list or set)
127.0.0.1:6379> info keyspace
# Keyspace
127.0.0.1:6379> set  id 11
OK
127.0.0.1:6379> keys *
1) "id"
127.0.0.1:6379> set  name "john"
OK
127.0.0.1:6379> keys *
1) "name"
2) "id"
127.0.0.1:6379> keys *
1) "name"
2) "id"
127.0.0.1:6379> flushdb async
OK
127.0.0.1:6379> keys *
(empty list or set)
127.0.0.1:6379>

Another way delete rdb and aof files.

- stop the Redis server
- Delete rdb and aof files 
- Start Redis Server
- It starts with an empty and blank database.


## How to delete LUA scripts from Redis database?

It provides SCRIPT FLUSH Command to delete all LUA scripts from database instance.

It delete all scripts from scripts cache.

Syntax:

```markup
SCRIPT FLUSH [Mode]

MODE is a modifier for flushing all scripts in a server. Values are ASYNC | SYNC. ASYNC: Deleting scripts with asynchronous. It was added since Redis 4.0.0 version SYNC: Delete scripts synchronously, Added since Redis 6.0.0 version

Here is an example

127.0.0.1:6379> script flush
OK