PostgreSQL for Data Architects

The background writer

The background writer is responsible for writing to disk specific dirty buffers based on an algorithm, whereas checkpointer writes all dirty buffers. The process takes into consideration shared memory usage data as well as information about which blocks have been used/accessed recently (least recently used). The primary objective of this process is to ensure that free buffers are available for use. The relevant parameters are as follows:

#bgwriter_delay = 200ms                 # 10-10000ms between rounds
#bgwriter_lru_maxpages = 100            # 0-1000 max buffers written/round
#bgwriter_lru_multiplier = 2.0          # 0-10.0 multiplier on buffers scanned/round

As we can see, the default value for delay is 200 milliseconds. This parameter specifies how long ...