Skip logical decoding of already-aborted transactions.
authorMasahiko Sawada <msawada@postgresql.org>
Thu, 13 Feb 2025 00:31:34 +0000 (16:31 -0800)
committerMasahiko Sawada <msawada@postgresql.org>
Thu, 13 Feb 2025 00:31:34 +0000 (16:31 -0800)
commit072ee847ad4c3fb52b0c24f7dddbe0798bd70c24
treeb77b3f475ec5fb5e2e649ac0f6f4f38d9f57df01
parent9e66a2b7841a5c1f929103c82c73244d3f5f3416
Skip logical decoding of already-aborted transactions.

Previously, transaction aborts were detected concurrently only during
system catalog scans while replaying a transaction in streaming mode.

This commit adds an additional CLOG lookup to check the transaction
status, allowing the logical decoding to skip changes also when it
doesn't touch system catalogs, if the transaction is already
aborted. This optimization enhances logical decoding performance,
especially for large transactions that have already been rolled back,
as it avoids unnecessary disk or network I/O.

To avoid potential slowdowns caused by frequent CLOG lookups for small
transactions (most of which commit), the CLOG lookup is performed only
for large transactions before eviction. The performance benchmark
results showed there is not noticeable performance regression due to
CLOG lookups.

Reviewed-by: Amit Kapila, Peter Smith, Vignesh C, Ajin Cherian
Reviewed-by: Dilip Kumar, Andres Freund
Discussion: https://postgr.es/m/CAD21AoDht9Pz_DFv_R2LqBTBbO4eGrpa9Vojmt5z5sEx3XwD7A@mail.gmail.com
contrib/test_decoding/expected/stats.out
contrib/test_decoding/expected/stream.out
contrib/test_decoding/sql/stats.sql
contrib/test_decoding/sql/stream.sql
src/backend/replication/logical/reorderbuffer.c
src/include/replication/reorderbuffer.h