Redis

To start the Redis plugin, enlist it in the server.plugins settings. To specify multiple plugins, use the comma , as separator. Example:

If you’re using MS Windows OS, replace server.sh with server.bat.

In case you’re running ArcadeDB with Docker, open the port 6379 and use -e to pass settings:

The Server output will contain this line:

ArcadeDB works in 2 ways with the Redis protocol:

Below you can find the supported commands. The link takes you to the official Redis documentation. Please open an issue or a discussion on GitHub to support more commands.

The following commands do not take the bucket as a parameter because they work only in RAM on a shared (thread-safe) hashmap. This means all the stored values are reset when the server restarts.

INCR, DECR, INCRBY and INCRBYFLOAT are atomic, as they are in Redis: concurrent clients incrementing the same key all count, and no update is lost. The guarantee is per server, though — these values are not replicated, so in an HA cluster two clients incrementing through different nodes each update their own node’s copy. The same applies to SET with NX/XX: it is a genuine check-and-set on one server, not a cluster-wide lock.

The commands check their argument count, over the Redis wire protocol and in the redis query language alike, and answer wrong number of arguments for '<command>' command when it is wrong, as Redis does: INCR and DECR take the key only, INCRBY, DECRBY and INCRBYFLOAT take the key and the amount (there is no default amount of 1), and a surplus argument is refused, never read as an amount. Amounts and stored values of INCR, INCRBY, DECR and DECRBY must be plain 64-bit integers (+5, 05 and -0 are refused with value is not an integer or out of range). INCRBYFLOAT replies and stores the result as decimal text, as Redis does (0.1 plus 0.2 is 0.3, an integral result is 3, not 3.0), so INCR works on an integral result. In the redis query language GET therefore returns a string for a key written by INCRBYFLOAT.

Available transient commands (in alphabetic order):

The following commands act on persistent buckets in the database. Records (documents, vertices and edges) are always in form of JSON embedded in strings. The bucket name is mapped as the database name first, then type, the index or the record’s RID based on the use case. An index must exist on the property you used to retrieve the document, otherwise an error is returned.

For the sake of this tutorial, in a database MyDatabase, we’re going to create the account document type totally schemaless but for some indexed properties: id as a unique long, email as a unique string and the pair firstName and lastName both strings and indexed with a composite key:

Now you can create a new document with Redis protocol and the HSET Redis command:

To retrieve the document inserted above by id (O(logN) complexity), you can use the HGET Redis command:

To retrieve the same document by email (O(logN) complexity), you can use the HGET Redis command:

To retrieve the same document by the pair firstName and lastName (O(logN) complexity), we are going to use the composite key we created before:

To retrieve the document inserted above by it RID (O(1) complexity), you can use the HGET Redis command:

You can also get multiple record in one call by using the HMGET Redis command:

Or the same, but by a key:

Or by a composite key, using the same […​] JSON array form HGET takes. A key with no record keeps its place in the reply as a null entry, so the Nth reply is always the answer to the Nth key:

To delete the document inserted above by email, you can use the HDEL Redis command:

Available persistent commands (in alphabetic order):

Available miscellaneous commands:

In addition to the native Redis wire protocol, ArcadeDB also supports Redis commands as a query language via the HTTP API. This allows you to execute Redis commands through the standard ArcadeDB HTTP /command endpoint by specifying language=redis.

This is useful when: