5.3. Process Management

process_management_mode (enum)

Specify the idle process management method for Pgpool-II child processes. Valid options:

Table 5-1. Possible Process Management Modes

static All children are pre-forked at startup. Number of child processes is fixed (num_init_children).
dynamicchild processes are spawned on demand up to num_init_children. Number of idle child processes at any time depends on min_spare_children and max_spare_children

Default is static, that is compatible with pre V4.4.

process_management_mode is not available prior to Pgpool-II V4.4.

See Section 3.3.3 for more details.

process_management_strategy (enum)

Specify the process management strategy to satisfy spare (idle) processes count Valid options:

Table 5-2. Possible Process Management Strategies

lazyWith this strategy the scale-down is performed gradually and only gets triggered when excessive spare processes count remains high for more than 5 mins
gentleWith this strategy the scale-down is performed gradually and only gets triggered when excessive spare processes count remains high for more than 2 mins
aggressiveWith this strategy the scale-down is performed aggressively and gets triggered more frequently in case of higher spare processes. This mode uses faster and slightly less smart process selection criteria to identify the child processes that can be serviced to satisfy max_spare_children

Default is gentle.

process_management_strategy is not available prior to Pgpool-II V4.4.

min_spare_children (integer)

Specify the minimum number of spare (idle) child processes to keep. If the idle process count falls below min_spare_children, Pgpool-II will spawn new child processes unless it hits the total allowed child process ceiling (num_init_children). Default value is 5.

This parameter can be changed by reloading the Pgpool-II configurations.

This parameter is only applicable for dynamic process management mode.

max_spare_children (integer)

Specify the maximum number of spare (idle) child processes to keep. If the idle process count increases from max_spare_children, Pgpool-II will kill the excessive child processes. Default value is 10.

This parameter can be changed by reloading the Pgpool-II configurations.

This parameter is only applicable for dynamic process management mode.