Type: integer
Default: 256 (256kB)
Min: 0 (0kB)
Max: 16777216 (16GB)
Unit: KB
Context: user
Restart: false
Since: 16

Specifies the size of the Buffer Access Strategy used by the VACUUM and ANALYZE commands. A setting of 0 will allow the operation to use any number of shared_buffers. Otherwise valid sizes range from 128 kB to 16 GB. If the specified size would exceed 1/8 the size of shared_buffers, the size is silently capped to that value. The default value is 256 kB. If this value is specified without units, it is taken as kilobytes. This parameter can be set at any time. It can be overridden for sql-vacuum and sql-analyze when passing the BUFFER_USAGE_LIMIT option. Higher settings can allow VACUUM and ANALYZE to run more quickly, but having too large a setting may cause too many other useful pages to be evicted from shared buffers.