diff options
Diffstat (limited to 'lib/gitlab/database/partitioning/replace_table.rb')
-rw-r--r-- | lib/gitlab/database/partitioning/replace_table.rb | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/lib/gitlab/database/partitioning/replace_table.rb b/lib/gitlab/database/partitioning/replace_table.rb new file mode 100644 index 00000000000..6f6af223fa2 --- /dev/null +++ b/lib/gitlab/database/partitioning/replace_table.rb @@ -0,0 +1,114 @@ +# frozen_string_literal: true + +module Gitlab + module Database + module Partitioning + class ReplaceTable + DELIMITER = ";\n\n" + + attr_reader :original_table, :replacement_table, :replaced_table, :primary_key_column, + :sequence, :original_primary_key, :replacement_primary_key, :replaced_primary_key + + def initialize(original_table, replacement_table, replaced_table, primary_key_column) + @original_table = original_table + @replacement_table = replacement_table + @replaced_table = replaced_table + @primary_key_column = primary_key_column + + @sequence = default_sequence(original_table, primary_key_column) + @original_primary_key = default_primary_key(original_table) + @replacement_primary_key = default_primary_key(replacement_table) + @replaced_primary_key = default_primary_key(replaced_table) + end + + def perform + yield sql_to_replace_table if block_given? + + execute(sql_to_replace_table) + end + + private + + delegate :execute, :quote_table_name, :quote_column_name, to: :connection + def connection + @connection ||= ActiveRecord::Base.connection + end + + def default_sequence(table, column) + "#{table}_#{column}_seq" + end + + def default_primary_key(table) + "#{table}_pkey" + end + + def sql_to_replace_table + @sql_to_replace_table ||= combined_sql_statements.map(&:chomp).join(DELIMITER) + end + + def combined_sql_statements + statements = [] + + statements << alter_column_default(original_table, primary_key_column, expression: nil) + statements << alter_column_default(replacement_table, primary_key_column, + expression: "nextval('#{quote_table_name(sequence)}'::regclass)") + + statements << alter_sequence_owned_by(sequence, replacement_table, primary_key_column) + + rename_table_objects(statements, original_table, replaced_table, original_primary_key, replaced_primary_key) + rename_table_objects(statements, replacement_table, original_table, replacement_primary_key, original_primary_key) + + statements + end + + def rename_table_objects(statements, old_table, new_table, old_primary_key, new_primary_key) + statements << rename_table(old_table, new_table) + statements << rename_constraint(new_table, old_primary_key, new_primary_key) + + rename_partitions(statements, old_table, new_table) + end + + def rename_partitions(statements, old_table_name, new_table_name) + Gitlab::Database::PostgresPartition.for_parent_table(old_table_name).each do |partition| + new_partition_name = partition.name.sub(/#{old_table_name}/, new_table_name) + old_primary_key = default_primary_key(partition.name) + new_primary_key = default_primary_key(new_partition_name) + + statements << rename_constraint(partition.identifier, old_primary_key, new_primary_key) + statements << rename_table(partition.identifier, new_partition_name) + end + end + + def alter_column_default(table_name, column_name, expression:) + default_clause = expression.nil? ? 'DROP DEFAULT' : "SET DEFAULT #{expression}" + + <<~SQL + ALTER TABLE #{quote_table_name(table_name)} + ALTER COLUMN #{quote_column_name(column_name)} #{default_clause} + SQL + end + + def alter_sequence_owned_by(sequence_name, table_name, column_name) + <<~SQL + ALTER SEQUENCE #{quote_table_name(sequence_name)} + OWNED BY #{quote_table_name(table_name)}.#{quote_column_name(column_name)} + SQL + end + + def rename_table(old_name, new_name) + <<~SQL + ALTER TABLE #{quote_table_name(old_name)} + RENAME TO #{quote_table_name(new_name)} + SQL + end + + def rename_constraint(table_name, old_name, new_name) + <<~SQL + ALTER TABLE #{quote_table_name(table_name)} + RENAME CONSTRAINT #{quote_column_name(old_name)} TO #{quote_column_name(new_name)} + SQL + end + end + end + end +end |