postgres/doc
Richard Guo 185e304263 Allow negative aggtransspace to indicate unbounded state size
This patch reuses the existing aggtransspace in pg_aggregate to
signal that an aggregate's transition state can grow unboundedly.  If
aggtransspace is set to a negative value, it now indicates that the
transition state may consume unpredictable or large amounts of memory,
such as in aggregates like array_agg or string_agg that accumulate
input rows.

This information can be used by the planner to avoid applying
memory-sensitive optimizations (e.g., eager aggregation) when there is
a risk of excessive memory usage during partial aggregation.

Bump catalog version.

Per idea from Robert Haas, though applied differently than originally
suggested.

Discussion: https://postgr.es/m/CA+TgmoYbkvYwLa+1vOP7RDY7kO2=A7rppoPusoRXe44VDOGBPg@mail.gmail.com
2025-10-08 17:01:48 +09:00
..
src Allow negative aggtransspace to indicate unbounded state size 2025-10-08 17:01:48 +09:00
KNOWN_BUGS
Makefile Remove distprep 2023-11-06 15:18:04 +01:00
MISSING_FEATURES
TODO Change documentation references to PG website to use https: not http: 2017-05-20 21:50:47 -04:00