TAG.SET

TAG.SET attaches labels to a key, so you can later find keys by label with TAG.MEMBERS and TAG.INTER, or filter vector searches with VSIM.SEARCH FILTER. A key can carry any number of tags, and a tag any number of keys. Tags that the key already has are left as they are.

The key must exist in the selected database when you tag it. Tags work with keys of any type.

How tags behave

• Tags are kept per key name and shared by all logical databases: tagging user:1 in database 0 also shows up for user:1 in database 1.
• A key’s tags go when the key does. That covers DEL, UNLINK, GETDEL, expiry, eviction, a command that empties the key (the last element popped from a list, the last member removed from a set, the last field removed from a hash), and FLUSHDB and FLUSHALL. A key created again under the same name starts with no tags. Overwriting a key that still exists, for example with SET, keeps its tags.
• RENAME and RENAMENX move the tags to the new name, and the tags of a key that a rename replaces are dropped. A RENAMENX that does nothing leaves the tags where they were. MOVE keeps the tags, because tags are shared by all databases.
• Tags are not part of snapshots, so re-apply them after a server restarts from a snapshot.

Return value

Case	RESP2	RESP3
Key exists	Integer: the number of tags newly attached	Integer

Error replies: ERR no such key when the key does not exist.

Examples

127.0.0.1:6379> SET article:1 "..."
OK
127.0.0.1:6379> TAG.SET article:1 news sports
(integer) 2
127.0.0.1:6379> TAG.SET article:1 sports europe
(integer) 1
127.0.0.1:6379> TAG.SET article:99 news
(error) ERR no such key

Compatibility

HotKV-only command.

See also

TAG.REM, TAG.GET, TAG.MEMBERS, TAG.INTER, VSIM.SEARCH