内容

pg_promote()

用于提升物理备用服务器的功能

pg_promote() 是一个 PostgreSQL 函数，用于将物理备用服务器提升为主服务器，或者更准确地说，是将备用服务器从恢复模式切换到读写模式。

pg_promote() 添加于 PostgreSQL 12。

用法

pg_promote ( wait boolean DEFAULT true, wait_seconds integer DEFAULT 60 ) → boolean

pg_promote() 提供了一种基于 SQL 的替代方法来执行 pg_ctl promote。

更改历史记录

示例

pg_promote() 的执行示例

postgres=# SELECT pg_is_in_recovery();
 pg_is_in_recovery
-------------------
 t
(1 row)

postgres=# SELECT pg_promote();
 pg_promote
------------
 t
(1 row)

postgres=# SELECT pg_is_in_recovery();
 pg_is_in_recovery
-------------------
 f
(1 row)

相应的日志输出

[2018-11-27 22:33:47 UTC] psql postgres postgres LOG:  00000: statement: SELECT pg_promote();
[2018-11-27 22:33:47 UTC] psql postgres postgres LOCATION:  exec_simple_query, postgres.c:1045
[2018-11-27 22:33:47 UTC]    LOG:  00000: received promote request
[2018-11-27 22:33:47 UTC]    LOCATION:  CheckForStandbyTrigger, xlog.c:12189
[2018-11-27 22:33:47 UTC]    FATAL:  57P01: terminating walreceiver process due to administrator command
[2018-11-27 22:33:47 UTC]    LOCATION:  ProcessWalRcvInterrupts, walreceiver.c:169
[2018-11-27 22:33:47 UTC]    LOG:  00000: invalid record length at 0/30005E8: wanted 24, got 0
[2018-11-27 22:33:47 UTC]    LOCATION:  ReadRecord, xlog.c:4258
[2018-11-27 22:33:47 UTC]    LOG:  00000: redo done at 0/30005B0
[2018-11-27 22:33:47 UTC]    LOCATION:  StartupXLOG, xlog.c:7286
[2018-11-27 22:33:47 UTC]    LOG:  00000: last completed transaction was at log time 2018-11-27 22:33:31.648668+09
[2018-11-27 22:33:47 UTC]    LOCATION:  StartupXLOG, xlog.c:7291
[2018-11-27 22:33:47 UTC]    LOG:  00000: selected new timeline ID: 2
[2018-11-27 22:33:47 UTC]    LOCATION:  StartupXLOG, xlog.c:7416
[2018-11-27 22:33:47 UTC]    LOG:  00000: archive recovery complete
[2018-11-27 22:33:47 UTC]    LOCATION:  exitArchiveRecovery, xlog.c:5557
[2018-11-27 22:33:47 UTC]    LOG:  00000: checkpoint starting: force
[2018-11-27 22:33:47 UTC]    LOCATION:  LogCheckpointStart, xlog.c:8381
[2018-11-27 22:33:47 UTC]    LOG:  00000: database system is ready to accept connections
[2018-11-27 22:33:47 UTC]    LOCATION:  reaper, postmaster.c:2944
[2018-11-27 22:33:47 UTC]    LOG:  00000: checkpoint complete: wrote 3 buffers (0.0%); 0 WAL file(s) added, 0 removed, 0 recycled; write=0.301 s, sync=0.000 s, total=0.302 s; sync files=0, longest=0.000 s, average=0.000 s; distance=16385 kB, estimate=16385 kB
[2018-11-27 22:33:47 UTC]    LOCATION:  LogCheckpointEnd, xlog.c:8463

分类

复制，系统函数

另请参阅

pg_ctl

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