Delete key if value matches string.
DELIFEQ key value
Deletes the key if its value matches the given string.
This command is typically used to safely release locks in distributed systems, ensuring that only the owner of the lock (as identified by the value) can delete it.
If the key exists and the stored value is a string that exactly
matches the provided value, the key is removed and 1 is
returned. Otherwise, the key is left unchanged and 0 is
returned.
One of the following:
Integer reply:
1 if the key was deleted.
Integer reply:
0 if the key was not deleted because it did not exist or
the value was not equal to the provided value.
O(1)
@fast @string @write
Basic usage:
127.0.0.1:6379> SET mykey abc123
OK
127.0.0.1:6379> DELIFEQ mykey abc123
(integer) 1
127.0.0.1:6379> DELIFEQ mykey abc123
(integer) 0Wrong value:
127.0.0.1:6379> SET mykey xyz789
OK
127.0.0.1:6379> DELIFEQ mykey abc123
(integer) 0Wrong type:
127.0.0.1:6379> SADD mykey somevalue
(integer) 1
127.0.0.1:6379> DELIFEQ mykey somevalue
(error) WRONGTYPE Operation against a key holding the wrong kind of valueDELIFEQ enables an atomic check-and-delete operation to
safely release a lock only if the process still holds it. This avoids
race conditions where a lock might expire and be claimed by another
process before the original owner tries to delete it.
This pattern is commonly used as part of distributed locking systems
like Redlock, which previously
relied on Lua scripting to implement this logic. With
DELIFEQ, such a use case becomes more robust and
idiomatic.
Instead of:
EVAL "if redis.call('GET',KEYS[1]) == ARGV[1] then return redis.call('DEL',KEYS[1]) else return 0 end" 1 mykey abc123You can now use:
DELIFEQ mykey abc123SET IFEQ - Sets the key only if
it matches the given value.APPEND, DECR, DECRBY, GET, GETDEL, GETEX, GETRANGE, GETSET, INCR, INCRBY, INCRBYFLOAT, LCS, MGET, MSET, MSETNX, PSETEX, SET, SETEX, SETNX, SETRANGE, STRLEN, SUBSTR.