Monitor CDC (logical replication) in YugabyteDB

Catalog objects and views

pg_publication

Contains all publication objects contained in the database.

Column name	Data type	Description
oid	oid	Row identifier
pubname	name	Name of the publication
pubowner	oid	OID of the owner.
puballtables	bool	If true, this publication includes all tables in the database including those added in the future.
pubinsert	bool	If true, INSERT operations are replicated for tables in the publication.
pubupdate	bool	If true, UPDATE operations are replicated for tables in the publication.
pubdelete	bool	If true, DELETE operations are replicated for tables in the publication.
pubtruncate	bool	If true, TRUNCATE operations are replicated for tables in the publication.

pg_publication_rel

Contains mapping between publications and tables. This is a many-to-many mapping.

Column name	Data type	Description
oid	oid	Row identifier.
prpubid	oid	OID of the publication. References pg_publication.oid.
prrelid	oid	OID of the relation. References pg_class.oid.

pg_publication_tables

Contains mapping between publications and tables. It is a wrapper over pg_publication_rel as it expands the publications defined as FOR ALL TABLES, so for such publications there will be a row for each eligible table.

Column name	Data type	Description
pubname	name	Name of publication.
schemaname	name	Name of schema containing table.
tablename	name	Name of table.

pg_replication_slots

Provides a list of all replication slots that currently exist on the database cluster, along with their metadata.

Column name	Data type	Description
slot_name	name	Name of the replication slot.
plugin	name	Output plugin name (Always yboutput).
slot_type	text	Always logical.
datoid	oid	The OID of the database this slot is associated with.
database	text	The name of the database this slot is associated with.
temporary	boolean	True if this is a temporary replication slot. Temporary slots are automatically dropped on error or when the session has finished.
active	boolean	True if this slot is currently actively being used. In YSQL, an "active" replication slot means a slot which has been consumed at least once in a certain time frame. The time is defined using the ysql_cdc_active_replication_slot_window_ms flag, which has a default of 5 minutes.
active_pid	integer	The process ID of the session using this slot if the slot is currently actively being used. NULL if no replication process is ongoing.
xmin	xid	The oldest transaction that this slot needs the database to retain.
catalog_xmin	xid	Not applicable for YSQL. Always set to xmin.
restart_lsn	pg_lsn	The Log Sequence Number (LSN) of the oldest change record which still might be required by the consumer of this slot and thus won't be automatically removed during checkpoints.
confirmed_flush_lsn	pg_lsn	The LSN up to which the logical slot's consumer has confirmed receiving data. Data older than this is not available anymore. Transactions with commit LSN lower than the confirmed_flush_lsn are not available anymore.
yb_stream_id	text	UUID of the CDC stream
yb_restart_commit_ht	int8	A uint64 representation of the commit Hybrid Time corresponding to the restart_lsn. This can be used by the client (like YugabyteDB connector) to perform a consistent snapshot (as of the consistent_point) in the case when a replication slot already exists.

CDC Service metrics

Provide information about CDC service in YugabyteDB.

Metric name	Type	Description
cdcsdk_change_event_count	long	The number of records sent by the CDC Service.
cdcsdk_traffic_sent	long	Total traffic sent, in bytes.
cdcsdk_sent_lag_micros	long	The LAG metric is calculated by subtracting the timestamp of the latest record in the WAL of a tablet from the last record sent to the CDC connector.
cdcsdk_expiry_time_ms	long	The time left to read records from WAL is tracked by the Stream Expiry Time (ms).

Connector metrics

<!-- TODO (Siddharth): Fix link to connector metrics section -->

Refer to Monitoring for information on YugabyteDB connector metrics.