On Sat, Jul 25, 2020 at 9:39 AM Peter Geoghegan <pg@bowt.ie> wrote:
> "Peak Memory Usage: 1605334kB"
>
> Hash agg avoids spilling entirely (so the planner gets it right this
> time around). It even uses notably less memory.
I guess that this is because the reported memory usage doesn't reflect
the space used for transition state, which is presumably most of the
total -- array_agg() is used in the query.
--
Peter Geoghegan