medium10 pts · first answer countsreplicationmonitoring

Measuring replica lag

On a PostgreSQL primary, which query best shows how far each streaming replica is behind?

A.SELECT * FROM pg_stat_user_tables;B.SELECT application_name, write_lag, flush_lag, replay_lag FROM pg_stat_replication;C.SELECT now() - pg_postmaster_start_time();D.SHOW max_wal_senders;

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