IO Parameters

temp_file_limit

Numeric type (disk space). Maximum disk space a process can use for temporary files (e.g., temporary files during sorting or hash computation). Transactions that exceed this limit will be canceled. Default value -1, meaning no disk usage limit. This parameter can only be set at instance startup.

temp_file_limit = -1            # limits per-process temp file space in kilobytes, or -1 for no limit

bgwriter_delay

Numeric type (time). Interval between write activities of the Background Writer process. Default value 200ms. This parameter can only be set at instance startup.

bgwriter_delay = 200ms            # 10-10000ms between rounds

bgwriter_lru_maxpages

Numeric type. Number of pages the Background Writer can write per round. Default value 100. Set to 0 to disable. This parameter can only be set at instance startup.

bgwriter_lru_maxpages = 100        # max buffers written/round, 0 disables

bgwriter_lru_multiplier

Numeric type. Used to estimate the number of pages the Background Writer needs to write in the next round. Default value 2.0, range 0~10.0. This parameter can be set during runtime.

bgwriter_lru_multiplier = 2.0        # 0-10.0 multiplier on buffers scanned/round

bgwriter_flush_after

Numeric type (memory). Threshold for forcing dirty data to be flushed to disk. Default value 512kB. Set to 0 to disable. This parameter can only be set at instance startup.

bgwriter_flush_after = 512kB        # measured in pages, 0 disables

effective_io_concurrency

Numeric type. Maximum number of concurrent I/O operations. Allowed range is 1~1000. Default value 1. This parameter can only be set at instance startup.

effective_io_concurrency = 1        # 1-1000; 0 disables prefetching

maintenance_io_concurrency

Numeric type. Similar to effective_io_concurrency, used for I/O concurrency during maintenance operations (such as VACUUM). Default value 10. This parameter can only be set at instance startup.

maintenance_io_concurrency = 200