RUBY-406 enhancements to :secondary_only read preference

Improved implementation
-- read_preference :secondary_only is now communicated via invocation
of ReplSetConnection#checkout_secondary

Better tests
-- ensures reads go to secondaries
-- ensures reads do not go to primaries
This commit is contained in:
Tyler Brock 2012-02-18 16:51:57 -05:00
parent b9371206dc
commit b70c9ce152
4 changed files with 57 additions and 11 deletions

View File

@ -522,6 +522,8 @@ module Mongo
@checkin_connection = true
if @command || @read_preference == :primary
socket = @connection.checkout_writer
elsif @read_preference == :secondary_only
socket = @connection.checkout_secondary
else
@read_pool = @connection.read_pool
socket = @connection.checkout_reader

View File

@ -321,7 +321,7 @@ module Mongo
end
begin
socket = get_socket_from_pool(self.read_pool)
if !socket && @read != :secondary_only
if !socket
connect
socket = get_socket_from_pool(self.primary_pool)
end
@ -336,6 +336,26 @@ module Mongo
raise ConnectionFailure.new("Could not connect to a node for reading.")
end
end
def checkout_secondary
if connected?
sync_refresh
else
connect
end
begin
socket = get_socket_from_pool(self.secondary_pool)
rescue => ex
checkin(socket) if socket
raise ex
end
if socket
socket
else
raise ConnectionFailure.new("Could not connect to a secondary for reading.")
end
end
# Checkout a socket for writing (i.e., a primary node).
def checkout_writer
@ -424,6 +444,10 @@ module Mongo
def read_pool
@manager ? @manager.read_pool : nil
end
def secondary_pool
@manager ? @manager.secondary_pool : nil
end
def secondary_pools
@manager ? @manager.secondary_pools : []

View File

@ -2,8 +2,8 @@ module Mongo
class PoolManager
attr_reader :connection, :arbiters, :primary, :secondaries, :primary_pool,
:read_pool, :secondary_pools, :hosts, :nodes, :max_bson_size,
:tags_to_pools, :tag_map, :members
:read_pool, :secondary_pool, :secondary_pools, :hosts, :nodes,
:max_bson_size, :tags_to_pools, :tag_map, :members
# Create a new set of connection pools.
#
@ -140,6 +140,7 @@ module Mongo
@read_pool = nil
@arbiters = []
@secondaries = []
@secondary_pool = nil
@secondary_pools = []
@hosts = Set.new
@members = Set.new
@ -232,12 +233,14 @@ module Mongo
# If more than one node is available, use the ping
# time to figure out which nodes to choose from.
def set_read_pool
if @secondary_pools.empty? && @connection.read_preference != :secondary_only
@read_pool = @primary_pool
if @secondary_pools.empty?
@read_pool = @primary_pool
elsif @secondary_pools.size == 1
@read_pool = @secondary_pools[0]
@read_pool = @secondary_pools[0]
@secondary_pool = @read_pool
else
@read_pool = nearby_pool_from_set(@secondary_pools)
@secondary_pool = @read_pool
end
end

View File

@ -34,17 +34,34 @@ class ReadPreferenceTest < Test::Unit::TestCase
end
def test_read_secondary_only
@conn = ReplSetConnection.new([@rs.host, @rs.ports[0]], [@rs.host, @rs.ports[1]], :read => :secondary_only)
assert_equal @conn.read_preference, :secondary_only
@rs.add_arbiter
@rs.remove_secondary_node
@conn = ReplSetConnection.new(["#{@rs.host}:#{@rs.ports[0]}","#{@rs.host}:#{@rs.ports[1]}"],
:read => :secondary_only)
@db = @conn.db(MONGO_TEST_DB)
@coll = @db.collection("test-sets")
@coll.save({:a => 20})
@rs.kill_all_secondaries
assert_raise ConnectionFailure do
@coll.save({:a => 20}, :safe => {:w => 2})
# Test that reads are going to secondary on ReplSetConnection
@secondary = Connection.new(@rs.host, @conn.read_pool.port, :slave_ok => true)
queries_before = @secondary['admin'].command({:serverStatus => 1})['opcounters']['query']
@coll.find_one
queries_after = @secondary['admin'].command({:serverStatus => 1})['opcounters']['query']
assert_equal 1, queries_after - queries_before
@rs.kill_secondary
@conn.refresh
# Test that reads are only allowed from secondaries
assert_raise ConnectionFailure.new("Could not connect to a secondary for reading.") do
@coll.find_one
end
@rs = ReplSetManager.new
@rs.start_set
end
def test_query_secondaries