Command: Delete

Deletes a key with persistent durability, for example when a service instance deregisters or a job record is no longer needed. Persistent keys are replicated and survive node failures. The key is ignored if it doesn't exist. The delete is recorded as a new revision, so historical reads from before the delete can still find the old value. For ephemeral keys, use edelete.

Syntax

delete <key>
del <key>

del is a short form of delete; both behave the same.

Examples

set `services/email/instance-3` '{"ip": "10.1.1.22", "port": 9090}'

r0 set 9ms

delete `services/email/instance-3`

r1 deleted 12ms

Checking the Result

Use if not deleted then ... end to test whether the last delete found no key. not set also treats a successful delete as a write that took effect. Deleting a key that never existed writes no tombstone, even if the transaction locked it. Within a transaction, set-then-delete deletes the staged value; deleting it again finds no key. See Statement-Result Guards.

Notes

Deleting a key does not immediately remove it from disk. Kahuna writes a tombstone, which hides the key from future reads.

The tombstone is its own revision. If the live value is at r0, the delete returns r1, and a later set returns r2. This preserves the pre-delete value for historical as of reads and point-in-time recovery.

Depending on the compaction policies of the underlying key/value store, these deleted keys (tombstones) may be fully removed later to reclaim disk space.