PostgreSQL 설계 · 이중화 · 튜닝 · 이관

# 1) 서비스 중지 후 목표 시점으로 복원
sudo systemctl stop postgresql
sudo -u postgres pgbackrest --stanza=main --delta \
     --type=time "--target=2026-10-20 13:55:00+09" \
     --target-action=promote restore
# 2) 기동 후 복구 완료 확인
sudo systemctl start postgresql
psql -c "select pg_is_in_recovery();"   -- f 이면 승격 완료

-- postgresql.conf: shared_preload_libraries = 'pg_stat_statements'
CREATE EXTENSION IF NOT EXISTS pg_stat_statements;
SELECT queryid, calls,
       round(total_exec_time::numeric, 1) AS total_ms,
       round(mean_exec_time::numeric, 2)  AS mean_ms,
       rows, left(query, 80) AS query
FROM pg_stat_statements
ORDER BY total_exec_time DESC
LIMIT 10;