class ActiveRecord::ConnectionAdapters::SchemaCache

Active Record Connection Adapters Schema Cache

Private Class Methods

read(filename) { |read| ... } click to toggle source
# File lib/active_record/connection_adapters/schema_cache.rb, line 244
def self.read(filename, &block)
  if File.extname(filename) == ".gz"
    Zlib::GzipReader.open(filename) { |gz|
      yield gz.read
    }
  else
    yield File.read(filename)
  end
end

Public Instance Methods

add(pool, table_name) click to toggle source

Add internal cache for table with table_name.

# File 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
cached?(table_name) click to toggle source
# File lib/active_record/connection_adapters/schema_cache.rb, line 294
def cached?(table_name)
  @columns.key?(table_name)
end
clear_data_source_cache!(_connection, name) click to toggle source

Clear out internal caches for the data source name.

# File 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
columns(pool, table_name) click to toggle source

Get the columns for a table

# File 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
columns_hash(pool, table_name) click to toggle source

Get the columns for a table as a hash, key is the column name value is the column object.

# File 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
columns_hash?(_pool, table_name) click to toggle source

Checks whether the columns hash is already cached for a table.

# File lib/active_record/connection_adapters/schema_cache.rb, line 359
def columns_hash?(_pool, table_name)
  @columns_hash.key?(table_name)
end
data_source_exists?(pool, name) click to toggle source

A cached lookup for table existence.

# File 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
dump_to(filename) click to toggle source
# File 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
indexes(pool, table_name) click to toggle source
# File 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
primary_keys(pool, table_name) click to toggle source
# File 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
schema_version() click to toggle source
# File lib/active_record/connection_adapters/schema_cache.rb, line 379
def schema_version
  @version
end
size() click to toggle source
# File lib/active_record/connection_adapters/schema_cache.rb, line 383
def size
  [@columns, @columns_hash, @primary_keys, @data_sources].sum(&:size)
end
version(pool) click to toggle source
# File lib/active_record/connection_adapters/schema_cache.rb, line 375
def version(pool)
  @version ||= pool.with_connection(&:schema_version)
end

Private Instance Methods

deep_deduplicate(value) click to toggle source
# File lib/active_record/connection_adapters/schema_cache.rb, line 448
def deep_deduplicate(value)
  case value
  when Hash
    value.transform_keys { |k| deep_deduplicate(k) }.transform_values { |v| deep_deduplicate(v) }
  when Array
    value.map { |i| deep_deduplicate(i) }
  when String, Deduplicable
    -value
  else
    value
  end
end
derive_columns_hash_and_deduplicate_values() click to toggle source
# File lib/active_record/connection_adapters/schema_cache.rb, line 440
def derive_columns_hash_and_deduplicate_values
  @columns      = deep_deduplicate(@columns)
  @columns_hash = @columns.transform_values { |columns| columns.index_by(&:name) }
  @primary_keys = deep_deduplicate(@primary_keys)
  @data_sources = deep_deduplicate(@data_sources)
  @indexes      = deep_deduplicate(@indexes)
end
ignored_table?(table_name) click to toggle source
# File lib/active_record/connection_adapters/schema_cache.rb, line 436
def ignored_table?(table_name)
  ActiveRecord.schema_cache_ignored_table?(table_name)
end
open(filename) { |zipper| ... } click to toggle source
# File lib/active_record/connection_adapters/schema_cache.rb, line 461
def open(filename)
  FileUtils.mkdir_p(File.dirname(filename))

  File.atomic_write(filename) do |file|
    if File.extname(filename) == ".gz"
      zipper = Zlib::GzipWriter.new file
      zipper.mtime = 0
      yield zipper
      zipper.flush
      zipper.close
    else
      yield file
    end
  end
end
tables_to_cache(pool) click to toggle source
# File lib/active_record/connection_adapters/schema_cache.rb, line 428
def tables_to_cache(pool)
  pool.with_connection do |connection|
    connection.data_sources.reject do |table|
      ignored_table?(table)
    end
  end
end