From 0f5b735685476ff51b26031e9b74fa8256354868 Mon Sep 17 00:00:00 2001 From: Stan Hu Date: Wed, 3 Apr 2019 22:00:29 -0700 Subject: [PATCH] Fix stage index migration failing in PostgreSQL 10 As discussed in https://www.postgresql.org/message-id/9922.1353433645%40sss.pgh.pa.us, the PostgreSQL window function last_value may not consider the right rows: Note that first_value, last_value, and nth_value consider only the rows within the "window frame", which by default contains the rows from the start of the partition through the last peer of the current row. This is likely to give unhelpful results for last_value and sometimes also nth_value. You can redefine the frame by adding a suitable frame specification (RANGE or ROWS) to the OVER clause. See Section 4.2.8 for more information about frame specifications. This query could be fixed by adding `RANGE BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING`, but that's quite verbose. It's simpler just to use the first_value function. Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/59985 --- lib/gitlab/background_migration/migrate_stage_index.rb | 4 ++-- .../gitlab/background_migration/migrate_stage_index_spec.rb | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/lib/gitlab/background_migration/migrate_stage_index.rb b/lib/gitlab/background_migration/migrate_stage_index.rb index f90f35a913d..f921233460d 100644 --- a/lib/gitlab/background_migration/migrate_stage_index.rb +++ b/lib/gitlab/background_migration/migrate_stage_index.rb @@ -21,8 +21,8 @@ module Gitlab AND stage_idx IS NOT NULL GROUP BY stage_id, stage_idx ), indexes AS ( - SELECT DISTINCT stage_id, last_value(stage_idx) - OVER (PARTITION BY stage_id ORDER BY freq ASC) AS index + SELECT DISTINCT stage_id, first_value(stage_idx) + OVER (PARTITION BY stage_id ORDER BY freq DESC) AS index FROM freqs ) diff --git a/spec/lib/gitlab/background_migration/migrate_stage_index_spec.rb b/spec/lib/gitlab/background_migration/migrate_stage_index_spec.rb index f8107dd40b9..4db829b1e7b 100644 --- a/spec/lib/gitlab/background_migration/migrate_stage_index_spec.rb +++ b/spec/lib/gitlab/background_migration/migrate_stage_index_spec.rb @@ -30,6 +30,6 @@ describe Gitlab::BackgroundMigration::MigrateStageIndex, :migration, schema: 201 described_class.new.perform(100, 101) - expect(stages.all.pluck(:position)).to eq [2, 3] + expect(stages.all.order(:id).pluck(:position)).to eq [2, 3] end end