OpenTelemetry integration

You can configure EDB Postgres Distributed to report monitoring information as well as traces to the OpenTelemetry collector.

EDB Postgres Distributed OTEL collector fills several resource attributes. These are attached to all metrics and traces:

• The service.name is configurable with the bdr.otel_service_name configuration setting. - The service.namespace is always set to edb_postgres_distributed . - The service.instance.id is always set to the system identifier of the Postgres instance. - The service.version is set to the current version of the BDR extension loaded in the Postgresql instance.

OTEL and OLTP compatibility

For OTEL connections the integration supports OLTP/HTTP version 1.0.0 only, over HTTP or HTTPS. It doesn’t support OLTP/gRPC.

Metrics collection

Setting the configuration option bdr.metrics_otel_http_url to a non-empty URL enables the metric collection.

Different kinds of metrics are collected as shown in the tables that follow.

Generic metrics

Metric name	Type	Labels	Description
pg_backends_by_state	gauge	conn_state - idle, active, idle in transaction, fastpath functioncall, idle in transaction (aborted), disabled, undefined	Number of backends in a given state
pg_oldest_xact_start	gauge		Oldest transaction start time
pg_oldest_activity_start	gauge		Oldest query start time
pg_waiting_backends	gauge	wait_type - LWLock, Lock, BufferPin, Activity, Client, Extension, IPC, Timeout, IO, ??? (for unknown)	Number of currently waiting backends by wait type
pg_start_time	gauge		Timestamp at which the server has started
pg_reload_time	gauge		Timestamp at which the server has last reloaded configuration

Replication metrics

Metric name	Type	Labels	Description
bdr_slot_sent_lag	gauge	slot_name - name of a slot	Current sent lag in bytes for each replication slot
bdr_slot_write_lag	gauge	slot_name - name of a slot	Current write lag in bytes for each replication slot
bdr_slot_flush_lag	gauge	slot_name - name of a slot	Current flush lag in bytes for each replication slot
bdr_slot_apply_lag	gauge	slot_name - name of a slot	Current apply lag in bytes for each replication slot
bdr_subscription_receive_lsn	gauge	sub_name - name of subscription	Current received LSN for each subscription
bdr_subscription_flush_lsn	gauge	sub_name - name of subscription	Current flushed LSN for each subscription
bdr_subscription_apply_lsn	gauge	sub_name - name of subscription	Current applied LSN for each subscription
bdr_subscription_receiver	gauge	sub_name - name of subscription	Whether subscription receiver is currently running (1) or not (0)

Consensus metric

See also Monitoring Raft consensus

Metric name	Type	Labels	Description
bdr_raft_state	gauge	state_str - RAFT_FOLLOWER, RAFT_CANDIDATE, RAFT_LEADER, RAFT_STOPPED	Raft state of the consensus on this node
bdr_raft_protocol_version	gauge		Consensus protocol version used by this node
bdr_raft_leader_node	gauge		Id of a node that this node considers to be current leader
bdr_raft_nodes	gauge		Total number of nodes that participate in consensus (includes learner/non-voting nodes)
bdr_raft_voting_nodes	gauge		Number of actual voting nodes in consensus
bdr_raft_term	gauge		Current raft term this node is on
bdr_raft_commit_index	gauge		Raft commit index committed by this node
bdr_raft_apply_index	gauge		Raft commit index applied by this node

Tracing

Tracing collection to OpenTelemetry requires configuring bdr.trace_otel_http_url and enabling tracing using bdr.trace_enable .

The tracing is limited to only some subsystems at the moment, primarily to the cluster management functionality. The following spans can be seen in traces.

Span name	Description
create_node_group	Group creation
alter_node_group_config	Change of group config options
alter_node_config	Change of node config option
join_node_group	Node joining a group
join_send_remote_request	Join source sending the join request on behalf of the joining node
add_camo_pair	Add CAMO pair
alter_camo_pair	Change CAMO pair
remove_camo_pair	Delete CAMO pair
alter_commit_scope	Change commit scope definition (either create new or update existing)
alter_proxy_config	Change config for PGD-Proxy instance (either create new or update existing)
walmsg_global_lock_send	Send global locking WAL message
walmsg_global_lock_recv	Received global locking WAL message
ddl_epoch_apply	Global locking epoch apply (ensure cluster is synchronized enough for new epoch to start)
walmsg_catchup	Catchup during node removal WAL message
raft_send_appendentries	Internal Raft book keeping message
raft_recv_appendentries	Internal Raft book keeping message
raft_request	Raft request execution
raft_query	Raft query execution
msgb_send	Consensus messaging layer message
msgb_recv_receive	Consensus messaging layer message
msgb_recv_deliver	Consensus messaging layer message delivery
preprocess_ddl	DDL command preprocessing

TLS support

The metrics and tracing endpoints can be HTTP or HTTPS. You can configure paths to the CA bundle, client key, and client certificate using bdr.otel_https_ca_path , bdr.otel_https_key_path , and bdr.otel_https_cert_path configuration options.