Streaming Replication Check
| pgpool-II 3.6.7 Documentation | |||
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Pgpool-II can work with PostgreSQL native Streaming Replication, that is available since PostgreSQL 9.0. To configure Pgpool-II with streaming replication, enable master_slave_mode and set master_slave_sub_mode to 'stream' .
Pgpool-II assumes that Streaming Replication is configured with Hot Standby on PostgreSQL, which means that the standby database can handle read-only queries.
- sr_check_period ( integer )
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Specifies the time interval in seconds to check the streaming replication delay. Default is 0, which means the check is disabled.
This parameter can be changed by reloading the Pgpool-II configurations.
- sr_check_user ( string )
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Specifies the PostgreSQL user name to perform streaming replication check. The user must exist on all the PostgreSQL backends.
Note: sr_check_user > and sr_check_password are used even when sr_check_period is set to 0 (disabled) for the identification of the primary server.
This parameter can be changed by reloading the Pgpool-II configurations.
- sr_check_password ( string )
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Specifies the password of the sr_check_user PostgreSQL user to perform the streaming replication checks. Use '' (empty string) if the user does not requires a password.
This parameter can be changed by reloading the Pgpool-II configurations.
- sr_check_database ( string )
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Specifies the database to perform streaming replication delay checks. The default is "postgres" .
This parameter can be changed by reloading the Pgpool-II configurations.
- delay_threshold ( integer )
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Specifies the maximum tolerance level of replication delay in WAL bytes on the standby server against the primary server. If the delay exceeds this configured level, Pgpool-II stops sending the SELECT queries to the standby server and starts routing everything to the primary server even if load_balance_mode is enabled, until the standby catches-up with the primary. Setting this parameter to 0 disables the delay checking. This delay threshold check is performed every sr_check_period . Default is 0.
This parameter can be changed by reloading the Pgpool-II conf igurations.
- log_standby_delay ( string )
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Specifies when to log the replication delay. Below table contains the list of all valid values for the parameter.
Table 5-9. Log standby delay options
Value Description 'none' Never log the standby delay 'always' Log the standby delay, every time the replication delay is checked 'if_over_threshold' Only log the standby delay, when it exceeds delay_threshold value This parameter can be changed by reloading the Pgpool-II configurations.