OBJECT ENCODING
OBJECT ENCODING key
- Available since:
- 2.2.3
- Time complexity:
- O(1)
- ACL categories:
-
@keyspace
,@read
,@slow
,
Returns the internal encoding for the Redis object stored at <key>
Redis objects can be encoded in different ways:
-
Strings can be encoded as:
raw
, normal string encoding.int
, strings representing integers in a 64-bit signed interval, encoded in this way to save space.embstr
, an embedded string, which is an object where the internal simple dynamic string,sds
, is an unmodifiable string allocated in the same chuck as the object itself.embstr
can be strings with lengths up to the hardcoded limit ofOBJ_ENCODING_EMBSTR_SIZE_LIMIT
or 44 bytes.
-
Lists can be encoded as
ziplist
orlinkedlist
. Theziplist
is the special representation that is used to save space for small lists. -
Sets can be encoded as
intset
orhashtable
. Theintset
is a special encoding used for small sets composed solely of integers. -
Hashes can be encoded as
ziplist
orhashtable
. Theziplist
is a special encoding used for small hashes. -
Sorted Sets can be encoded as
ziplist
orskiplist
format. As for the List type small sorted sets can be specially encoded usingziplist
, while theskiplist
encoding is the one that works with sorted sets of any size.
All the specially encoded types are automatically converted to the general type once you perform an operation that makes it impossible for Redis to retain the space saving encoding.
RESP2 Reply
One of the following:
- Nil reply: if the key doesn't exist.
- Bulk string reply: the encoding of the object.
RESP3 Reply
One of the following:
- Null reply: if the key doesn't exist.
- Bulk string reply: the encoding of the object.