Commit c1e756c2 authored by Yorick Peterse's avatar Yorick Peterse

Fix update_column_in_batches to update all rows

This changes update_column_in_batches to ensure it always updates all
rows now. These changes also allow for an extra SELECT query to be
removed, nor does it use the row count for determining offsets and the
likes; instead it's only used to determine the batch size.
parent 816c4535
......@@ -30,7 +30,7 @@ module Gitlab
# This method updates the table in batches of 5% of the total row count.
# This method will continue updating rows until no rows remain.
#
# When given a block this method will yield to values to the block:
# When given a block this method will yield two values to the block:
#
# 1. An instance of `Arel::Table` for the table that is being updated.
# 2. The query to run as an Arel object.
......@@ -44,59 +44,63 @@ module Gitlab
# query.where(table[:some_column].eq('hello'))
# end
#
# This would result in this method updating only rows there
# This would result in this method updating only rows where
# `projects.some_column` equals "hello".
#
# table - The name of the table.
# column - The name of the column to update.
# value - The value for the column.
#
# Rubocop's Metrics/AbcSize metric is disabled for this method as Rubocop
# determines this method to be too complex while there's no way to make it
# less "complex" without introducing extra methods (which actually will
# make things _more_ complex).
#
# rubocop: disable Metrics/AbcSize
def update_column_in_batches(table, column, value)
table = Arel::Table.new(table)
processed = 0
count_arel = table.project(Arel.star.count.as('count'))
count_arel = yield table, count_arel if block_given?
total = exec_query(count_arel.to_sql).to_hash.first['count'].to_i
return if total == 0
# Update in batches of 5% until we run out of any rows to update.
batch_size = ((total / 100.0) * 5.0).ceil
loop do
start_arel = table.project(table[:id]).
order(table[:id].asc).
take(1).
skip(processed)
start_arel = table.project(table[:id]).order(table[:id].asc).take(1)
start_arel = yield table, start_arel if block_given?
start_row = exec_query(start_arel.to_sql).to_hash.first
# There are no more rows to process
break unless start_row
start_id = exec_query(start_arel.to_sql).to_hash.first['id'].to_i
loop do
stop_arel = table.project(table[:id]).
where(table[:id].gteq(start_id)).
order(table[:id].asc).
take(1).
skip(processed + batch_size)
skip(batch_size)
stop_arel = yield table, stop_arel if block_given?
stop_row = exec_query(stop_arel.to_sql).to_hash.first
update_manager = Arel::UpdateManager.new(ActiveRecord::Base)
update_arel = update_manager.table(table).
update_arel = Arel::UpdateManager.new(ActiveRecord::Base).
table(table).
set([[table[column], value]]).
where(table[:id].gteq(start_row['id']))
update_arel = yield table, update_arel if block_given?
where(table[:id].gteq(start_id))
if stop_row
update_arel = update_arel.where(table[:id].lt(stop_row['id']))
stop_id = stop_row['id'].to_i
start_id = stop_id
update_arel = update_arel.where(table[:id].lt(stop_id))
end
update_arel = yield table, update_arel if block_given?
execute(update_arel.to_sql)
processed += batch_size
# There are no more rows left to update.
break unless stop_row
end
end
......
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