patronictl -c /etc/patroni/patroni.yml show-config > /root/patroni-dcs-backup.yml

patronictl -c /etc/patroni/patroni.yml show-config

loop_wait: 10
maximum_lag_on_failover: 1048576
postgresql:
  parameters:
    hot_standby: 'on'
    max_replication_slots: 10
    max_wal_senders: 10
    wal_level: replica
    wal_log_hints: 'on'
  pg_hba:
  - local all postgres peer
  - local all all peer
  - host all all 127.0.0.1/32 scram-sha-256
  - host all all ::1/128 scram-sha-256
  - host replication replicator 10.89.60.0/24 scram-sha-256
  - host all all 10.89.60.0/24 scram-sha-256
  use_pg_rewind: true
retry_timeout: 10
ttl: 30

curl -s http://10.89.60.11:8008/config

{"ttl": 30, "loop_wait": 10, "retry_timeout": 10, "maximum_lag_on_failover": 1048576, "postgresql": {"use_pg_rewind": true, "parameters": {"wal_level": "replica", "hot_standby": "on", "max_wal_senders": 10, "max_replication_slots": 10, "wal_log_hints": "on"}, "pg_hba": ["local all postgres peer", "local all all peer", "host all all 127.0.0.1/32 scram-sha-256", "host all all ::1/128 scram-sha-256", "host replication replicator 10.89.60.0/24 scram-sha-256", "host all all 10.89.60.0/24 scram-sha-256"]}}

  cluster_name           The name of the cluster
  -f FILE, --file FILE   Apply changes from an existing file to the cluster's DCS configuration
  -s SET, --set SET      Set specific configuration value. It has the highest priority. Can be repeated. Example: -s ttl=100
  -p SET, --pg SET       Set specific postgresql parameter. It has the second-highest priority. Can be repeated. Example: -p max_connections=100
  -r SET, --remove SET   Remove configuration parameter. Can be repeated. Example: -r postgresql.use_slots
  --force                Apply changes without showing them and without confirmation
  -q, --quiet            Do not show changes
  -y, --yes              Apply changes without confirmation

patronictl -c /etc/patroni/patroni.yml edit-config pgdemo -p max_wal_senders=12

---
+++
@@ -4,7 +4,7 @@
   parameters:
     hot_standby: 'on'
     max_replication_slots: 10
-    max_wal_senders: 10
+    max_wal_senders: 12
     wal_level: replica
     wal_log_hints: 'on'
   pg_hba:
Configuration changed

Oct 19 16:58:58 pgnode1 patroni[7876]: 2026-10-19 16:58:58.827 UTC [7876] LOG:  parameter "max_wal_senders" cannot be changed without restarting the server

Oct 19 16:59:12 pgnode1 patroni[7849]: 2026-10-19 16:59:12,042 INFO: Changed max_wal_senders from '10' to '12'

patronictl -c /etc/patroni/patroni.yml restart pgdemo pgnode1 --force

├─7876 /usr/lib/postgresql/17/bin/postgres -D /var/lib/postgresql/17/pgdemo --config-file=/var/lib/postgresql/17/pgdemo/postgresql.conf --listen_addresses=0.0.0.0 --port=5432 --cluster_name=pgdemo --wal_level=replica --hot_standby=on --max_connections=100 --max_wal_senders=12 --max_prepared_transactions=0 --max_locks_per_transaction=64 --track_commit_timestamp=off --max_replication_slots=10 --max_worker_processes=8 --wal_log_hints=on

scope: pgdemo          # 集群名：etcd 中 /service/pgdemo/* 之下的 key 归属本集群
namespace: /service/   # key 空间前缀；同一路 DCS 跑多套集群时用不同 namespace 隔离
name: pgnode1          # 本节点全局唯一名，出现在 patronictl list 与 REST API 中

restapi:
  listen: 0.0.0.0:8008        # REST API 监听地址与端口
  connect_address: 10.89.60.11:8008   # 本节点对外宣告的 REST 地址（其他节点用它连自己）
  # verify_client: none       # 证书校验模式：none/optional/required（配 ssl 段使用）
  # authentication:           # 开启后 patronictl/REST 需 Basic 认证
  #   username: admin
  #   password: q1w2e3r4

etcd3:
  hosts: 10.89.60.11:2379,10.89.60.12:2379,10.89.60.13:2379   # etcd 集群全部成员，逗号分隔

bootstrap:
  dcs:
    ttl: 30                       # 领导者租约时长（秒）
    loop_wait: 10                 # 主循环轮询周期（秒）
    retry_timeout: 10             # 对 DCS/PG 操作的重试超时（秒）
    maximum_lag_on_failover: 1048576   # 候选从库最大落后字节数（1MB）
    postgresql:
      use_pg_rewind: true         # 允许用 pg_rewind 回卷旧主
      use_slots: true             # 使用物理复制槽保护 WAL（默认 true）
      parameters:                 # 写入 postgresql.conf 的参数（DCS 动态管理）
        wal_level: replica
        hot_standby: 'on'
        max_wal_senders: 10
        max_replication_slots: 10
        wal_log_hints: 'on'
      pg_hba:                     # 初始 pg_hba 规则（DCS 动态管理）
        - local all postgres peer
        - local all all peer
        - host all all 127.0.0.1/32 scram-sha-256
        - host all all ::1/128 scram-sha-256
        - host replication replicator 10.89.60.0/24 scram-sha-256
        - host all all 10.89.60.0/24 scram-sha-256

bootstrap:
  dcs: {…}                     # 见 5.4
  initdb:                      # 首节点 initdb 参数列表
    - encoding: UTF8
    - data-checksums           # 开启数据校验和（也是 pg_rewind 的前提之一）
  # post_bootstrap: /var/lib/postgresql/init_user.sh   # 引导完成后执行的脚本（4.0 起创建业务用户的正确姿势）
  # method:                    # 从库克隆方式，默认 pg_basebackup，可扩展 wal_g/pgbackrest
  #   pg_basebackup:
  #     max_rate: 100M
  #     network_partition_timeout: 10

postgresql:
  listen: 0.0.0.0:5432                # PG 监听（PG12+ 无需设置 port 参数，由 listen 拆分）
  connect_address: 10.89.60.11:5432   # 本节点 PG 对外宣告地址（主库身份信息）
  data_dir: /var/lib/postgresql/17/pgdemo   # 数据目录，Patroni 全权管理
  bin_dir: /usr/lib/postgresql/17/bin       # PG 可执行文件目录（pg_ctl/pg_rewind/pg_basebackup）
  # config_dir: /etc/postgresql/17/pgdemo   # 可选：postgresql.conf 外置目录；不设则放 data_dir
  parameters:
    unix_socket_directories: /var/run/postgresql   # 本地参数（仅本节点生效，不属于 DCS）
  authentication:
    superuser:
      username: postgres
      password: q1w2e3r4
    replication:
      username: replicator
      password: q1w2e3r4
    # rewind:
    #   username: rewind_user          # 不设则自动复用 superuser 凭据执行 pg_rewind
  # callbacks:                        # 角色变化回调脚本（on_start/on_stop/on_restart/on_role_change）
  #   on_role_change: /etc/patroni/vip.sh
  # create_replica_methods:           # 自定义克隆通道（pgbackrest/wal_g/basebackup）

tags:
  nofailover: false      # true=本节点永不参与选主（可作纯查询从库）
  noloadbalance: false   # true=HAProxy 健康检查 /replica 对本节点返回 503（下线读写流量）
  clonefrom: false       # true=新节点加入时优先从本节点克隆（指定备份源）
  nosync: false          # true=同步复制模式下本节点不被选为 sync standby

# === 在 bootstrap.dcs.postgresql.parameters 中追加（DCS 动态域，全集群生效）===
#      shared_buffers: '4GB'              # 25% 内存
#      effective_cache_size: '12GB'       # 操作系统缓存预算，约 75% 内存
#      work_mem: '32MB'                   # OLTP 混合负载基线，复杂排序多的业务再上调
#      maintenance_work_mem: '1GB'
#      max_connections: 200               # 配合 PgBouncer 使用，本值给直连预算
#      max_wal_size: '8GB'                # SSD 上放宽以减少 checkpoint 抖动
#      checkpoint_completion_target: 0.9
#      wal_compression: 'on'
#      log_min_duration_statement: 1000   # 慢 SQL 记录阈值 ms
#      autovacuum_max_workers: 4
#      autovacuum_vacuum_scale_factor: 0.05
#      track_io_timing: 'on'

# === 节点本地建议 ===
#   systemd 单元追加：
#     Environment=MALLOC_ARENA_MAX=1      # 官方 README 建议，规避 Python 3.11+ 内存池膨胀
#   同步复制零丢失（可接受写入延迟时）：
#     bootstrap.dcs 下追加 synchronous_mode: true
#   维护通道加固：
#     restapi 开启 authentication 或 ssl