Background

Here we provide background information about the different components of LeanXcale as well as the ports where they run.

LeanXcale Components

Before installing, it is important to know that LeanXcale has a distributed architecture and it consists of several components:

  • lxqe: Query engine in charge of processing SQL queries.

  • kvds: Data server of the storage subsystem. There might be multiple instances.

  • kvms: Metadata server of the storage subsystem.

  • lxmeta: Metadata process for LeanXcale. It keeps metadata and services needed for other components.

  • stats: Optional monitoring subsystem to see resource usage and performance KPIs of LeanXcale database.

  • odata: Optional OpenDATA server to support a SQL REST API.

There are other components not described above, used by the system, that are not relevant for the user and are not described here. For example, spread is a communication bus used by LeanXcale components.

Query processing is performed partially on the query engine (lxqe) and partially on the storage engines (kvds). A query has a query plan and all algebraic operators below joins are pushed down to kvds and the joins and any operator above are processed by the query engine (lxqe).

LeanXcale Ports

The components listen on network ports to provide services to other components and to client applications:

  • Ports 9100, 9090 and 3003 are used by the stats subsystem, when installed.

  • The base port for all other components is 14000. (i.e. ports are in the 14000-14999 range).

  • Each component has a port assigned, but is free to use the following 4 ports too.

  • odata (when installed) uses ports at base plus 4, i.e., 14004.

  • spread uses ports at base plus 444, i.e., 14444.

  • lxmeta uses ports at base plus 410, i.e. 14410.

  • lxqe uses ports at base plus 420. The first instance at a host is at port 14420, the next one at 14424, another one at 14428, etc.

  • kvms uses ports at base plus 400, i.e. 14400.

  • kvds uses ports at base plus 500, i.e. 14500. When more than one kvds is configured, following instances at the host will use 14504, 14508, etc.