Add fallback for PostgreSQL without upsert in CopyStatusStats (#8903)

Fix #8590
This commit is contained in:
Eugen Rochko 2018-10-07 04:40:37 +02:00
parent a1b904441e
commit 485dc7d559

View file

@ -3,15 +3,10 @@ class CopyStatusStats < ActiveRecord::Migration[5.2]
def up
safety_assured do
Status.unscoped.select('id').find_in_batches(batch_size: 5_000) do |statuses|
execute <<-SQL.squish
INSERT INTO status_stats (status_id, reblogs_count, favourites_count, created_at, updated_at)
SELECT id, reblogs_count, favourites_count, created_at, updated_at
FROM statuses
WHERE id IN (#{statuses.map(&:id).join(', ')})
ON CONFLICT (status_id) DO UPDATE
SET reblogs_count = EXCLUDED.reblogs_count, favourites_count = EXCLUDED.favourites_count
SQL
if supports_upsert?
up_fast
else
up_slow
end
end
end
@ -19,4 +14,41 @@ class CopyStatusStats < ActiveRecord::Migration[5.2]
def down
# Nothing
end
private
def supports_upsert?
version = select_one("SELECT current_setting('server_version_num') AS v")['v'].to_i
version >= 90500
end
def up_fast
say 'Upsert is available, importing counters using the fast method'
Status.unscoped.select('id').find_in_batches(batch_size: 5_000) do |statuses|
execute <<-SQL.squish
INSERT INTO status_stats (status_id, reblogs_count, favourites_count, created_at, updated_at)
SELECT id, reblogs_count, favourites_count, created_at, updated_at
FROM statuses
WHERE id IN (#{statuses.map(&:id).join(', ')})
ON CONFLICT (status_id) DO UPDATE
SET reblogs_count = EXCLUDED.reblogs_count, favourites_count = EXCLUDED.favourites_count
SQL
end
end
def up_slow
say 'Upsert is not available in PostgreSQL below 9.5, falling back to slow import of counters'
# We cannot use bulk INSERT or overarching transactions here because of possible
# uniqueness violations that we need to skip over
Status.unscoped.select('id, reblogs_count, favourites_count, created_at, updated_at').find_each do |status|
begin
params = [[nil, status.id], [nil, status.reblogs_count], [nil, status.favourites_count], [nil, status.created_at], [nil, status.updated_at]]
exec_insert('INSERT INTO status_stats (status_id, reblogs_count, favourites_count, created_at, updated_at) VALUES ($1, $2, $3, $4, $5)', nil, params)
rescue ActiveRecord::RecordNotUnique
next
end
end
end
end