Updated on 2023-10-23 GMT+08:00

PG_STAT_REPLICATION

PG_STAT_REPLICATION displays information about log synchronization status, such as the locations of the sender sending logs and the receiver receiving logs.

Table 1 PG_STAT_REPLICATION columns

Name

Type

Description

pid

bigint

Process ID of the thread

usesysid

oid

User system ID

usename

name

Username

application_name

text

Program name

client_addr

inet

Client address

client_hostname

text

Client name

client_port

integer

Port of the client

backend_start

timestamp with time zone

Start time of the program

state

text

Log replication state:

  • Catch-up state
  • Consistent streaming state

sender_sent_location

text

Location where the sender sends logs

receiver_write_location

text

Location where the receiver writes logs

receiver_flush_location

text

Location where the receive end flushes logs

receiver_replay_location

text

Location where the receive end replays logs

sync_priority

integer

Priority of synchronous duplication (0 indicates asynchronization.)

sync_state

text

Synchronization state

  • Asynchronous replication
  • Synchronous replication
  • Potential synchronization
  • Qurom: switches between the synchronous and asynchronous states to ensure that there are more than a certain number of synchronous standby servers. Generally, the number of synchronous standby servers is (n+1)/2-1, where n indicates the total number of copies. Whether the standby server is synchronous depends on whether logs are received first. For details, see the description of the synchronous_standby_names parameter.