node list v5.6
Lists all nodes in the EDB Postgres Distributed cluster and their summary
Synopsis
Lists all nodes in the EDB Postgres Distributed cluster and their summary, including name, node id, group, and current/target state.
Node States
State | Description |
---|---|
NONE | Node state is unset when the worker starts, expected to be set quickly to the current known state. |
CREATED | bdr.create_node() has been executed, but the node isn't a member of any EDB Postgres Distributed cluster yet. |
JOIN_START | bdr.join_node_group() begins to join the local node to an existing EDB Postgres Distributed cluster. |
JOINING | The node join has started and is currently at the initial sync phase, creating the schema and data on the node. |
CATCHUP | Initial sync phase is complete; now the join is at the last step of retrieving and applying transactions that were performed on the upstream peer node since the join started. |
STANDBY | Node join has finished, but not yet started to broadcast changes. All joins spend some time in this state, but if defined as a Logical Standby, the node will continue in this state. |
PROMOTE | Node was a logical standby and we just called bdr.promote_node to move the node state to ACTIVE. These two PROMOTE states have to be coherent to the fact, that only one node can be with a state higher than STANDBY but lower than ACTIVE. |
PROMOTING | Promotion from logical standby to full BDR node is in progress. |
ACTIVE | The node is a full BDR node and is currently ACTIVE. This is the most common node status. |
PART_START | Node was ACTIVE or STANDBY and we just called bdr.part_node to remove the node from the EDB Postgres Distributed cluster. |
PARTING | Node disconnects from other nodes and plays no further part in consensus or replication. |
PART_CATCHUP | Non-parting nodes synchronize any missing data from the recently parted node. |
PARTED | Node parting operation is now complete on all nodes. |
Only one node at a time can be in either of the states PROMOTE or PROMOTING.
Note that the read-only state of a node, as shown in the Current State or in the Target State columns, is indicated as STANDBY.
Examples
Listing all the nodes in a simple cluster
In this example with a 3 node cluster, bdr-a1 and witness-a are up, bdr-a2 is down.
Listing all the nodes in a multi-group cluster
In this example with a multi-group cluster with witness, logical standby and subscriber-only nodes.
Note how the subscriber-only nodes are fully joined node to the cluster, and contrast that with logical standby.