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| author | Peter Geoghegan <pg@bowt.ie> | 2020-07-28 16:58:59 -0700 |
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| committer | Peter Geoghegan <pg@bowt.ie> | 2020-07-28 16:58:59 -0700 |
| commit | e362f469c50f6e671285640cc2087345ab55a9b2 (patch) | |
| tree | b84fdaa6af9ab1c801e8bbe1845401e317f62719 /src/backend/executor/nodeHashjoin.c | |
| parent | a57c837e5cdf601d6ec05e5e10a40d01f1d2b84e (diff) | |
| download | postgresql-e362f469c50f6e671285640cc2087345ab55a9b2.tar.gz postgresql-e362f469c50f6e671285640cc2087345ab55a9b2.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/executor/nodeHashjoin.c')
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