Active Record 连接适配器 Schema 缓存

# File activerecord/lib/active_record/connection_adapters/schema_cache.rb, line 326
def add(pool, table_name)
  pool.with_connection do
    if data_source_exists?(pool, table_name)
      primary_keys(pool, table_name)
      columns(pool, table_name)
      columns_hash(pool, table_name)
      indexes(pool, table_name)
    end
  end
end

# File activerecord/lib/active_record/connection_adapters/schema_cache.rb, line 294
def cached?(table_name)
  @columns.key?(table_name)
end

# File activerecord/lib/active_record/connection_adapters/schema_cache.rb, line 388
def clear_data_source_cache!(_connection, name)
  @columns.delete name
  @columns_hash.delete name
  @primary_keys.delete name
  @data_sources.delete name
  @indexes.delete name
end

# File activerecord/lib/active_record/connection_adapters/schema_cache.rb, line 338
def columns(pool, table_name)
  if ignored_table?(table_name)
    raise ActiveRecord::StatementInvalid.new("Table '#{table_name}' doesn't exist", connection_pool: pool)
  end

  @columns.fetch(table_name) do
    pool.with_connection do |connection|
      @columns[deep_deduplicate(table_name)] = deep_deduplicate(connection.columns(table_name))
    end
  end
end

# File activerecord/lib/active_record/connection_adapters/schema_cache.rb, line 352
def columns_hash(pool, table_name)
  @columns_hash.fetch(table_name) do
    @columns_hash[deep_deduplicate(table_name)] = columns(pool, table_name).index_by(&:name).freeze
  end
end

# File activerecord/lib/active_record/connection_adapters/schema_cache.rb, line 359
def columns_hash?(_pool, table_name)
  @columns_hash.key?(table_name)
end

# File activerecord/lib/active_record/connection_adapters/schema_cache.rb, line 309
def data_source_exists?(pool, name)
  return if ignored_table?(name)

  if @data_sources.empty?
    tables_to_cache(pool).each do |source|
      @data_sources[source] = true
    end
  end

  return @data_sources[name] if @data_sources.key? name

  @data_sources[deep_deduplicate(name)] = pool.with_connection do |connection|
    connection.data_source_exists?(name)
  end
end

# File activerecord/lib/active_record/connection_adapters/schema_cache.rb, line 406
def dump_to(filename)
  open(filename) { |f|
    if filename.include?(".dump")
      f.write(Marshal.dump(self))
    else
      f.write(YAML.dump(self))
    end
  }
end

# File activerecord/lib/active_record/connection_adapters/schema_cache.rb, line 363
def indexes(pool, table_name)
  @indexes.fetch(table_name) do
    pool.with_connection do |connection|
      if data_source_exists?(pool, table_name)
        @indexes[deep_deduplicate(table_name)] = deep_deduplicate(connection.indexes(table_name))
      else
        []
      end
    end
  end
end

# File activerecord/lib/active_record/connection_adapters/schema_cache.rb, line 298
def primary_keys(pool, table_name)
  @primary_keys.fetch(table_name) do
    pool.with_connection do |connection|
      if data_source_exists?(pool, table_name)
        @primary_keys[deep_deduplicate(table_name)] = deep_deduplicate(connection.primary_key(table_name))
      end
    end
  end
end

# File activerecord/lib/active_record/connection_adapters/schema_cache.rb, line 379
def schema_version
  @version
end

# File activerecord/lib/active_record/connection_adapters/schema_cache.rb, line 383
def size
  [@columns, @columns_hash, @primary_keys, @data_sources].sum(&:size)
end

# File activerecord/lib/active_record/connection_adapters/schema_cache.rb, line 375
def version(pool)
  @version ||= pool.with_connection(&:schema_version)
end