~jk

In the script we stored all the statements per connection reset the statement stack as soon as a transaction is closed.

    --[[

    print the statements of all transactions as soon as one of them aborted

    for now we know about:
    * Lock wait timeout exceeded
    * Deadlock found when trying to get lock

    --]]

    if not proxy.global.trxs then
            proxy.global.trxs = { }
    end

    function read_query(packet)
            if packet:byte() ~= proxy.COM_QUERY then return end

            if not proxy.global.trxs[proxy.connection.server.thread_id] then
                    proxy.global.trxs[proxy.connection.server.thread_id] = { }
            end

            proxy.queries:append(1, packet)

            local t = proxy.global.trxs[proxy.connection.server.thread_id]

            t[#t + 1] = packet:sub(2)

            return proxy.PROXY_SEND_QUERY
    end

    function read_query_result(inj)
            local res = inj.resultset
            local flags = res.flags

            if res.query_status == proxy.MYSQLD_PACKET_ERR then
                    local err_code     = res.raw:byte(2) + (res.raw:byte(3) * 256)
                    local err_sqlstate = res.raw:sub(5, 9)
                    local err_msg      = res.raw:sub(10)
                    -- print("-- error-packet: " .. err_code)

                    if err_code == 1205 or     -- Lock wait timeout exceeded
                       err_code == 1213 then   -- Deadlock found when trying to get lock
                            print(("[%d] received a ERR(%d, %s), dumping all active transactions"):format(
                                    proxy.connection.server.thread_id,
                                    err_code,
                                    err_msg))

                            for thread_id, statements in pairs(proxy.global.trxs) do
                                    for stmt_id, statement in ipairs(statements) do
                                            print(("  [%d].%d: %s"):format(thread_id, stmt_id, statement))
                                    end
                            end
                    end
            end

            -- we are done, free the statement list
            if not flags.in_trans then
                    proxy.global.trxs[proxy.connection.server.thread_id] = nil
            end
    end

    function disconnect_client()
            proxy.global.trxs[proxy.connection.server.thread_id] = nil
    end