From 15438e2abc8a70b07af2c09c7d33fcfe9e3a0e9a Mon Sep 17 00:00:00 2001 From: naisila Date: Sun, 7 Dec 2025 22:29:50 +0300 Subject: [PATCH] Explain why we have alternative multi_mx_hide_shard_names --- src/test/regress/expected/multi_mx_hide_shard_names.out | 6 ++++++ src/test/regress/expected/multi_mx_hide_shard_names_0.out | 6 ++++++ src/test/regress/sql/multi_mx_hide_shard_names.sql | 6 ++++++ 3 files changed, 18 insertions(+) diff --git a/src/test/regress/expected/multi_mx_hide_shard_names.out b/src/test/regress/expected/multi_mx_hide_shard_names.out index abd739c91..3ba366f62 100644 --- a/src/test/regress/expected/multi_mx_hide_shard_names.out +++ b/src/test/regress/expected/multi_mx_hide_shard_names.out @@ -1,6 +1,12 @@ -- -- Hide shard names on MX worker nodes -- +-- PostgreSQL 18 planner changes (probably AIO and updated cost model) make +-- sequential scans cheaper, so the psql `\d table`-style query that uses a +-- regex on `pg_class.relname` no longer chooses an index scan. This causes +-- a plan difference. +-- Alternative test output can be removed when we drop PG17 support +-- ALTER SEQUENCE pg_catalog.pg_dist_shardid_seq RESTART 1130000; -- make sure that the signature of the citus_table_is_visible -- and pg_table_is_visible are the same since the logic diff --git a/src/test/regress/expected/multi_mx_hide_shard_names_0.out b/src/test/regress/expected/multi_mx_hide_shard_names_0.out index 6f08cd87c..03960e4f0 100644 --- a/src/test/regress/expected/multi_mx_hide_shard_names_0.out +++ b/src/test/regress/expected/multi_mx_hide_shard_names_0.out @@ -1,6 +1,12 @@ -- -- Hide shard names on MX worker nodes -- +-- PostgreSQL 18 planner changes (probably AIO and updated cost model) make +-- sequential scans cheaper, so the psql `\d table`-style query that uses a +-- regex on `pg_class.relname` no longer chooses an index scan. This causes +-- a plan difference. +-- Alternative test output can be removed when we drop PG17 support +-- ALTER SEQUENCE pg_catalog.pg_dist_shardid_seq RESTART 1130000; -- make sure that the signature of the citus_table_is_visible -- and pg_table_is_visible are the same since the logic diff --git a/src/test/regress/sql/multi_mx_hide_shard_names.sql b/src/test/regress/sql/multi_mx_hide_shard_names.sql index b0636d3b6..3d1bb7ad9 100644 --- a/src/test/regress/sql/multi_mx_hide_shard_names.sql +++ b/src/test/regress/sql/multi_mx_hide_shard_names.sql @@ -1,6 +1,12 @@ -- -- Hide shard names on MX worker nodes -- +-- PostgreSQL 18 planner changes (probably AIO and updated cost model) make +-- sequential scans cheaper, so the psql `\d table`-style query that uses a +-- regex on `pg_class.relname` no longer chooses an index scan. This causes +-- a plan difference. +-- Alternative test output can be removed when we drop PG17 support +-- ALTER SEQUENCE pg_catalog.pg_dist_shardid_seq RESTART 1130000;