Upward compatibility of pg_promoter is pg_keeper.
pg_promoter is simplified clustring module for PostgreSQL.
pg_promoter module is available only on standby server side. pg_promoter polls to primary server every pg_promoter.keepalive_time second using simple query 'SELECT 1'. If pg_promoter failed to poll at pg_promoter.keepalive_count time(s), pg_promoter will promote the standby server to master server, and then exit itself. That is, fail over time can be calculated with this formula.
F/O time = pg_promoter.keepalives_time * pg_promoter.keepalives_count
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pg_promoter.primary_conninfo Specifies a connection string to be used for pg_promoter to connect to master server. This value must be specified in postgresql.conf, and must be same as primary_conninfo in recovery.conf.
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pg_promoter.keepalive_time (sec) Specifies how long interval pg_promoter continues polling. Deafult value is 5 secound.
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pg_promoter.keepalive_count Specifies how many times pg_promoter try polling to master server in ordre to promote standby server. Default value is 1 times.
$ cd pg_promoter
$ make USE_PGXS=1
$ su
# make USE_PGXS=1 install
$ vi postgresql.conf
shared_preload_libraries = 'pg_promoter'
pg_promoter.keepalive_time = 5
pg_promoter.keepalive_count = 3
pg_promoter.primary_conninfo = 'host=192.168.100.100 port=5432 dbname=postgres'