Type: | real |
Default: | 1 |
Min: | 1 |
Max: | 1000 |
Context: | user |
Restart: | false |
Since: | 13 |
Used to compute the maximum amount of memory that hash-based operations can use. The final limit is determined by multiplying work_mem by hash_mem_multiplier
. The default value is 1.0, which makes hash-based operations subject to the same simple work_mem maximum as sort-based operations.
Consider increasing hash_mem_multiplier
in environments where spilling by query operations is a regular occurrence, especially when simply increasing work_mem results in memory pressure (memory pressure typically takes the form of intermittent out of memory errors). A setting of 1.5 or 2.0 may be effective with mixed workloads. Higher settings in the range of 2.0 - 8.0 or more may be effective in environments where work_mem has already been increased to 40MB or more.