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# frozen_string_literal: true
namespace :gitlab do
namespace :db do
namespace :decomposition do
namespace :rollback do
SEQUENCE_NAME_MATCHER = /nextval\('([a-z_]+)'::regclass\)/.freeze
desc 'Bump all the CI tables sequences on the Main Database'
task :bump_ci_sequences, [:increase_by] => :environment do |_t, args|
increase_by = args.increase_by.to_i
if increase_by < 1
puts 'Please specify a positive integer `increase_by` value'.color(:red)
puts 'Example: rake gitlab:db:decomposition:rollback:bump_ci_sequences[100000]'.color(:green)
exit 1
end
sequences_by_gitlab_schema(ApplicationRecord, :gitlab_ci).each do |sequence_name|
increment_sequence_by(ApplicationRecord.connection, sequence_name, increase_by)
end
end
end
end
end
end
# base_model is to choose which connection to use to query the tables
# gitlab_schema, can be 'gitlab_main', 'gitlab_ci', 'gitlab_shared'
def sequences_by_gitlab_schema(base_model, gitlab_schema)
tables = Gitlab::Database::GitlabSchema.tables_to_schema.select do |_table_name, schema_name|
schema_name == gitlab_schema
end.keys
models = tables.map do |table|
model = Class.new(base_model)
model.table_name = table
model
end
sequences = []
models.each do |model|
model.columns.each do |column|
match_result = column.default_function&.match(SEQUENCE_NAME_MATCHER)
next unless match_result
sequences << match_result[1]
end
end
sequences
end
# This method is going to increase the sequence next_value by:
# - increment_by + 1 if the sequence has the attribute is_called = True (which is the common case)
# - increment_by if the sequence has the attribute is_called = False (for example, a newly created sequence)
# It uses ALTER SEQUENCE as a safety mechanism to avoid that no concurrent insertions
# will cause conflicts on the sequence.
# This is because ALTER SEQUENCE blocks concurrent nextval, currval, lastval, and setval calls.
def increment_sequence_by(connection, sequence_name, increment_by)
connection.transaction do
# The first call is to make sure that the sequence's is_called value is set to `true`
# This guarantees that the next call to `nextval` will increase the sequence by `increment_by`
connection.select_value("SELECT nextval($1)", nil, [sequence_name])
connection.execute("ALTER SEQUENCE #{sequence_name} INCREMENT BY #{increment_by}")
connection.select_value("select nextval($1)", nil, [sequence_name])
connection.execute("ALTER SEQUENCE #{sequence_name} INCREMENT BY 1")
end
end
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