How to dispatch select to a certain backend?

[xu ning]

by using inherited function read_query below, I just print the received select query. But how to dispatch the query to a certain backend, say backend 1?

function read_query( packet )
local cmd = commands.parse(packet)
local tokens

tokens = tokens or assert(tokenizer.tokenize(cmd.query))
local stmt = tokenizer.first_stmt_token(tokens)

if stmt.token_name == "TK_SQL_SELECT" then
local query = string.sub(packet, 2)
print ("received " .. query)
return proxy.PROXY_SEND_QUERY
end
end