Re: has anyone a working rw-splitting.lua for proxy v0.8.1?

[sharif uddin]

This works with me. But on the read slaves make sure user has update privileges





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---
-- a flexible statement based load balancer with connection pooling
--
-- * build a connection pool of min_idle_connections for each backend and maintain
-- its size
-- *
--
--

local commands = require("proxy.commands")
local tokenizer = require("proxy.tokenizer")
local lb = require("proxy.balance")
local auto_config = require("proxy.auto-config")

--- config
--
-- connection pool
if not proxy.global.config.rwsplit then
proxy.global.config.rwsplit = {
min_idle_connections = 4,
max_idle_connections = 8,

is_debug = false
}
end

---
-- read/write splitting sends all non-transactional SELECTs to the slaves
--
-- is_in_transaction tracks the state of the transactions
local is_in_transaction = false

-- if this was a SELECT SQL_CALC_FOUND_ROWS ... stay on the same connections
local is_in_select_calc_found_rows = false

---
-- get a connection to a backend
--
-- as long as we don't have enough connections in the pool, create new connections
--
function connect_server()
local is_debug = proxy.global.config.rwsplit.is_debug
-- make sure that we connect to each backend at least ones to
-- keep the connections to the servers alive
--
-- on read_query we can switch the backends again to another backend

if is_debug then
print()
print("[connect_server] " .. proxy.connection.client.src.name)
end

local rw_ndx = 0

-- init all backends
for i = 1, #proxy.global.backends do
local s = proxy.global.backends
local pool = s.pool -- we don't have a username yet, try to find a connections which is idling
local cur_idle = pool.users[""].cur_idle_connections

pool.min_idle_connections = proxy.global.config.rwsplit.min_idle_connections
pool.max_idle_connections = proxy.global.config.rwsplit.max_idle_connections

if is_debug then
print(" [".. i .."].connected_clients = " .. s.connected_clients)
print(" [".. i .."].pool.cur_idle = " .. cur_idle)
print(" [".. i .."].pool.max_idle = " .. pool.max_idle_connections)
print(" [".. i .."].pool.min_idle = " .. pool.min_idle_connections)
print(" [".. i .."].type = " .. s.type)
print(" [".. i .."].state = " .. s.state)
end

-- prefer connections to the master
if s.type == proxy.BACKEND_TYPE_RW and
s.state ~= proxy.BACKEND_STATE_DOWN and
cur_idle < pool.min_idle_connections then
proxy.connection.backend_ndx = i
break
elseif s.type == proxy.BACKEND_TYPE_RO and
s.state ~= proxy.BACKEND_STATE_DOWN and
cur_idle < pool.min_idle_connections then
proxy.connection.backend_ndx = i
break
elseif s.type == proxy.BACKEND_TYPE_RW and
s.state ~= proxy.BACKEND_STATE_DOWN and
rw_ndx == 0 then
rw_ndx = i
end
end

if proxy.connection.backend_ndx == 0 then
if is_debug then
print(" [" .. rw_ndx .. "] taking master as default")
end
proxy.connection.backend_ndx = rw_ndx
end

-- pick a random backend
--
-- we someone have to skip DOWN backends

-- ok, did we got a backend ?

if proxy.connection.server then
if is_debug then
print(" using pooled connection from: " .. proxy.connection.backend_ndx)
end

-- stay with it
return proxy.PROXY_IGNORE_RESULT
end

if is_debug then
print(" [" .. proxy.connection.backend_ndx .. "] idle-conns below min-idle")
end

-- open a new connection
end

---
-- put the successfully authed connection into the connection pool
--
-- @param auth the context information for the auth
--
-- auth.packet is the packet
function read_auth_result( auth )
if is_debug then
print("[read_auth_result] " .. proxy.connection.client.src.name)
end
if auth.packet:byte() == proxy.MYSQLD_PACKET_OK then
-- auth was fine, disconnect from the server
proxy.connection.backend_ndx = 0
elseif auth.packet:byte() == proxy.MYSQLD_PACKET_EOF then
-- we received either a
--
-- * MYSQLD_PACKET_ERR and the auth failed or
-- * MYSQLD_PACKET_EOF which means a OLD PASSWORD (4.0) was sent
print("(read_auth_result) ... not ok yet");
elseif auth.packet:byte() == proxy.MYSQLD_PACKET_ERR then
-- auth failed
end
end


---
-- read/write splitting
function read_query( packet )
local is_debug = proxy.global.config.rwsplit.is_debug
local cmd = commands.parse(packet)
local c = proxy.connection.client

local r = auto_config.handle(cmd)
if r then return r end

local tokens
local norm_query

-- looks like we have to forward this statement to a backend
if is_debug then
print("[read_query] " .. proxy.connection.client.src.name)
print(" current backend = " .. proxy.connection.backend_ndx)
print(" client default db = " .. c.default_db)
print(" client username = " .. c.username)
if cmd.type == proxy.COM_QUERY then
print(" query = " .. cmd.query)
end
end

if cmd.type == proxy.COM_QUIT then
-- don't send COM_QUIT to the backend. We manage the connection
-- in all aspects.
proxy.response = {
type = proxy.MYSQLD_PACKET_OK,
}

if is_debug then
print(" (QUIT) current backend = " .. proxy.connection.backend_ndx)
end

return proxy.PROXY_SEND_RESULT
end

proxy.queries:append(1, packet, { resultset_is_needed = true })

-- read/write splitting
--
-- send all non-transactional SELECTs to a slave
if not is_in_transaction and
cmd.type == proxy.COM_QUERY then
tokens = tokens or assert(tokenizer.tokenize(cmd.query))

local stmt = tokenizer.first_stmt_token(tokens)

if stmt.token_name == "TK_SQL_SELECT" then
is_in_select_calc_found_rows = false
local is_insert_id = false

for i = 1, #tokens do
local token = tokens
-- SQL_CALC_FOUND_ROWS + FOUND_ROWS() have to be executed
-- on the same connection
-- print("token: " .. token.token_name)
-- print(" val: " .. token.text)

if not is_in_select_calc_found_rows and (token.token_name == "TK_SQL_SQL_CALC_FOUND_ROWS" or (token.token_name == "TK_FUNCTION" and token.text:upper() == "FOUND_ROWS")) then
is_in_select_calc_found_rows = true
elseif not is_insert_id and token.token_name == "TK_FUNCTION" and token.text:upper() == "LAST_INSERT_ID" then
is_insert_id = true
elseif not is_insert_id and token.token_name == "TK_LITERAL" then
local utext = token.text:upper()

if utext == "@@INSERT_ID" then
is_insert_id = true
end
end

-- we found the two special token, we can't find more
if is_insert_id and is_in_select_calc_found_rows then
break
end
end

-- if we ask for the last-insert-id we have to ask it on the original
-- connection
if is_insert_id then
-- print(" found a SELECT LAST_INSERT_ID(), going to master")
elseif is_in_select_calc_found_rows then
print(" need to calculate the rows, going to master")
else -- neither of these two, pick an idle slave
local backend_ndx = lb.idle_ro()
if backend_ndx > 0 then
proxy.connection.backend_ndx = backend_ndx
end
end
end
end

-- no backend selected yet, pick a master
if proxy.connection.backend_ndx == 0 then
-- we don't have a backend right now
--
-- let's pick a master as a good default
--
proxy.connection.backend_ndx = lb.idle_failsafe_rw()
end

-- by now we should have a backend
--
-- in case the master is down, we have to close the client connections
-- otherwise we can go on
if proxy.connection.backend_ndx == 0 then
return proxy.PROXY_SEND_QUERY
end

local s = proxy.connection.server

-- if client and server db don't match, adjust the server-side
--
-- skip it if we send a INIT_DB anyway
if cmd.type ~= proxy.COM_INIT_DB and
c.default_db and c.default_db ~= s.default_db then
-- print(" server default db: " .. s.default_db)
-- print(" client default db: " .. c.default_db)
-- print(" syncronizing")
proxy.queries:prepend(2, string.char(proxy.COM_INIT_DB) .. c.default_db, { resultset_is_needed = true })
end

-- send to master
if is_debug then
if proxy.connection.backend_ndx > 0 then
local b = proxy.global.backends[proxy.connection.backend_ndx]
print(" sending to backend : " .. b.dst.name);
print(" is_slave : " .. tostring(b.type == proxy.BACKEND_TYPE_RO));
print(" server default db: " .. s.default_db)
print(" server username : " .. s.username)
end
print(" in_trans : " .. tostring(is_in_transaction))
print(" in_calc_found : " .. tostring(is_in_select_calc_found_rows))
print(" COM_QUERY : " .. tostring(cmd.type == proxy.COM_QUERY))
end

return proxy.PROXY_SEND_QUERY
end

---
-- as long as we are in a transaction keep the connection
-- otherwise release it so another client can use it
function read_query_result( inj )
local is_debug = proxy.global.config.rwsplit.is_debug
local res = assert(inj.resultset)
local flags = res.flags

if inj.id ~= 1 then
-- ignore the result of the USE <default_db>
-- the DB might not exist on the backend, what do do ?
--
if inj.id == 2 then
-- the injected INIT_DB failed as the slave doesn't have this DB
-- or doesn't have permissions to read from it
if res.query_status == proxy.MYSQLD_PACKET_ERR then
proxy.queries:reset()

proxy.response = {
type = proxy.MYSQLD_PACKET_ERR,
errmsg = "can't change DB ".. proxy.connection.client.default_db ..
" to on slave " .. proxy.global.backends[proxy.connection.backend_ndx].dst.name
}

return proxy.PROXY_SEND_RESULT
end
end
return proxy.PROXY_IGNORE_RESULT
end

is_in_transaction = flags.in_trans
local have_last_insert_id = (res.insert_id and (res.insert_id > 0))

if not is_in_transaction and
not is_in_select_calc_found_rows and
not have_last_insert_id then
-- release the backend
proxy.connection.backend_ndx = 0
elseif is_debug then
print("(read_query_result) staying on the same backend")
print(" in_trans : " .. tostring(is_in_transaction))
print(" in_calc_found : " .. tostring(is_in_select_calc_found_rows))
print(" have_insert_id : " .. tostring(have_last_insert_id))
end
end

---
-- close the connections if we have enough connections in the pool
--
-- @return nil - close connection
-- IGNORE_RESULT - store connection in the pool
function disconnect_client()
local is_debug = proxy.global.config.rwsplit.is_debug
if is_debug then
print("[disconnect_client] " .. proxy.connection.client.src.name)
end

-- make sure we are disconnection from the connection
-- to move the connection into the pool
proxy.connection.backend_ndx = 0
end