Andrew Lazarus <andrew(at)pillette(dot)com> writes:
> Should I temporarily increase sort_mem, vacuum_mem, neither, or both
> when doing a CLUSTER on a large (100 million row) table
The only part of that job that can use lots of memory is the index
rebuilds. In recent PG versions maintenance_work_mem is the thing
to increase for an index build; previously sort_mem controlled it.
I forget when the changeover was; maybe 8.0.
regards, tom lane