PostgreSQL

slot_name name

A unique, cluster-wide identifier for the replication slot

plugin name

The base name of the shared object containing the output plugin this logical slot is using, or null for physical slots.

slot_type text

The slot type: physical or logical

datoid oid (references pg_database.oid)

The OID of the database this slot is associated with, or null. Only logical slots have an associated database.

database name (references pg_database.datname)

The name of the database this slot is associated with, or null. Only logical slots have an associated database.

temporary bool

True if this is a temporary replication slot. Temporary slots are not saved to disk and are automatically dropped on error or when the session has finished.

active bool

True if this slot is currently actively being used

active_pid int4

The process ID of the session using this slot if the slot is currently actively being used. NULL if inactive.

xmin xid

The oldest transaction that this slot needs the database to retain. VACUUM cannot remove tuples deleted by any later transaction.

catalog_xmin xid

The oldest transaction affecting the system catalogs that this slot needs the database to retain. VACUUM cannot remove catalog tuples deleted by any later transaction.

restart_lsn pg_lsn

The address (LSN) of oldest WAL which still might be required by the consumer of this slot and thus won’t be automatically removed during checkpoints unless this LSN gets behind more than max_slot_wal_keep_size from the current LSN. NULL if the LSN of this slot has never been reserved.

confirmed_flush_lsn pg_lsn

The address (LSN) up to which the logical slot’s consumer has confirmed receiving data. Data older than this is not available anymore. NULL for physical slots.

wal_status text

Availability of WAL files claimed by this slot. Possible values are:

The last two states are seen only when max_slot_wal_keep_size is non-negative. If restart_lsn is NULL, this field is null.

safe_wal_size int8

The number of bytes that can be written to WAL such that this slot is not in danger of getting in state "lost". It is NULL for lost slots, as well as if max_slot_wal_keep_size is -1.