Set an Expiry on an Existing Redis Key Only When the Key Doesn’t Already Have an Expiry

When setting an expiry for an existing key in Redis, we now have the option to set the expiry only if the key doesn’t already have an expiry. That’s because Redis 7.0.0 introduced some new options that allows us to do this and other things.

In this case, we can use the NX option when setting the expiry to specify that the expiry should only be set if the key doesn’t already have an expiry. We can use this option on commands such as EXPIRE, EXPIREAT, PEXPIRE, and PEXPIREAT.

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Redis BLMOVE Command Explained

In Redis, the BLMOVE command is the blocking variant of LMOVE.

When the specified list contains elements, it atomically returns and removes either the first or last element of the given source list, and pushes the element at either the first or last element of the specified destination list. Whether it’s the first or last element depends on the arguments passed to the command.

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Redis LMOVE Command Explained

In Redis, the LMOVE command atomically returns and removes either the first or last element of the given source list, and pushes the element at either the first or last element of the specified destination list.

Whether it’s the first or last element depends on the arguments passed to the command.

The LMOVE command can be used in place of the RPOPLPUSH command, which has been deprecated since Redis 6.2.0.

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Redis LRANGE Command Explained

In Redis, the LRANGE command returns the specified elements of the list stored at the specified key.

The command requires us to specify a start and stop position for the elements to return. These are zero based indexes, so 0 is the first element in the list.

We can specify -1 for the last element in the list.

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