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| author | Peter Geoghegan <pg@bowt.ie> | 2020-07-28 16:59:01 -0700 |
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| committer | Peter Geoghegan <pg@bowt.ie> | 2020-07-28 16:59:01 -0700 |
| commit | f36e82072c8866ba2eca08d88d1a5c3e0c3d1eb4 (patch) | |
| tree | 38d79105d0ad7e01d76f7d0d3ced38d30b5d5711 /src/backend/utils/adt/json.c | |
| parent | 0e3e1c4e1cea68073132fe817fb3a98cb5c1b805 (diff) | |
| download | postgresql-f36e82072c8866ba2eca08d88d1a5c3e0c3d1eb4.tar.gz postgresql-f36e82072c8866ba2eca08d88d1a5c3e0c3d1eb4.zip | |
Doc: Remove obsolete CREATE AGGREGATE note.
The planner is in fact willing to use hash aggregation when work_mem is
not set high enough for everything to fit in memory. This has been the
case since commit 1f39bce0, which added disk-based hash aggregation.
There are a few remaining cases in which hash aggregation is avoided as
a matter of policy when the planner surmises that spilling will be
necessary. For example, callers of choose_hashed_setop() still
conservatively avoid hash aggregation when spilling is anticipated.
That doesn't seem like a good enough reason to mention hash aggregation
in this context.
Backpatch: 13-, where disk-based hash aggregation was introduced.
Diffstat (limited to 'src/backend/utils/adt/json.c')
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