862092932c
Otherwise, a read of blocks the stream is about to throw away can be
started and then waited for. read_stream_reset drains the stream by
calling read_stream_next_buffer, whose look-ahead treats the zeroed
distance as end of stream, leading to it spuriously performing the
pending read. This caused a pathological regression for a nested loop
antijoin query when run with the upcoming index prefetching patch series
applied.
This bug affects all stable branches with the read stream, which was
added to Postgres 17 by commit b5a9b18cd0. No backpatch for now,
though, since without index prefetching the added overhead for realistic
query plans is negligible.
Author: Tomas Vondra <tomas@vondra.me>
Discussion: https://postgr.es/m/CAH2-WzkKY8b42sZSPWJceT5Fn_THk3ZgcaM8ch3Hzw+XvhP0zQ@mail.gmail.com
PostgreSQL Database Management System
This directory contains the source code distribution of the PostgreSQL database management system.
PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings.
Copyright and license information can be found in the file COPYRIGHT.
General documentation about this version of PostgreSQL can be found at https://www.postgresql.org/docs/devel/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/devel/installation.html.
The latest version of this software, and related software, may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.