Using native MySQL driver in Erlang
- by Mickey Shine
I am using native MySQL driver (http://code.google.com/p/erlang-mysql-driver/) with mochiweb. When I tried that MySQL driver in shell mode, all woked fine. But when I write some code with Mochiweb, it reported me the following error:
=CRASH REPORT==== 4-Jul-2009::04:44:29 ===
crasher:
initial call: mochiweb_socket_server:acceptor_loop/1
pid: <0.61.0>
registered_name: []
exception error: no function clause matching
mysql:fetch(p1,<<"SELECT * FROM cdb_forums LIMIT 10">>)
in function perly_web:loop/2
in call from mochiweb_http:headers/5
ancestors: [perly_web,perly_sup,<0.58.0>]
messages: []
links: [<0.60.0>,#Port<0.965>]
dictionary: [{mochiweb_request_body,undefined},
{mochiweb_request_qs,[]},
{mochiweb_request_post,[]},
{mochiweb_request_path,"/online"},
{mochiweb_request_cookie,
[{"04c_sid","hG9Oyv"},
{"04c_visitedfid","2"},
{"kQx_cookietime","2592000"},
{"kQx_loginuser","admin"},
{"kQx_activationauth",
"98b3mdX86fKT9dI4WyKuL61Tqxk%2BW1r6ACpHp9y8itH2xQ"},
{"smile","1D1"}]}]
trap_exit: false
status: running
heap_size: 1597
stack_size: 24
reductions: 5188
neighbours:
The code I write in Mochiweb is
start(Options) ->
{DocRoot, Options1} = get_option(docroot, Options),
Loop = fun (Req) ->
?MODULE:loop(Req, DocRoot)
end,
% we’ll set our maximum to 1 million connections. (default: 2048)
mochiweb_http:start([{max, 1000000}, {name, ?MODULE}, {loop, Loop} | Options1]),
mysql:start_link(p1, "10.0.0.123", "root", "root", "test").
stop() ->
mochiweb_http:stop(?MODULE).
loop(Req, DocRoot) ->
"/" ++ Path = Req:get(path),
case Req:get(method) of
Method when Method =:= 'GET'; Method =:= 'HEAD' ->
case Path of
"online" ->
Result1 = mysql:fetch(p1, <<"SELECT * FROM cdb_forums LIMIT 10">>),
Body1 = io:format("Result1: ~p~n", [Result1]),
Req:ok({"text/plain", Body1});
The connection looks good but when I added
Result1 = mysql:fetch(p1, <<"SELECT * FROM cdb_forums LIMIT 10">>),
it crashed.
Can someone help me? Thanks in advance~
//==================================================
updated:
I noticed the follwoing information. If that is correct?
=PROGRESS REPORT==== 4-Jul-2009::05:49:32 ===
supervisor: {local,kernel_safe_sup}
started: [{pid,<0.65.0>},
{name,inet_gethost_native_sup},
{mfa,{inet_gethost_native,start_link,[]}},
{restart_type,temporary},
{shutdown,1000},
{child_type,worker}]
mysql_conn: greeting version "5.1.33-log" (protocol 10) salt "ne0_m'vA" caps 63487 serverchar <<8,2,0,0,
0,0,0,0,
0,0,0,0,
0,0,0,0>> salt2 "!|o;vabJ*4bt"
mysql_auth send packet 1: <<5,162,0,0,64,66,15,0,8,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,114,111,111,116,0,20,52,235,78,
173,36,251,201,242,172,139,113,231,253,181,245,3,
91,198,111,135>>
Link: {ok,<0.62.0>}
=SUPERVISOR REPORT==== 4-Jul-2009::05:49:32 ===
Supervisor: {local,perly_sup}
Context: start_error
Reason: ok
Offender: [{pid,undefined},
{name,perly_web},
{mfa,
{perly_web,start,
[[{ip,"0.0.0.0"},
{port,8000},
{docroot,
"/work/mochiweb-read-only/scripts/perly/priv/www"}]]}},
{restart_type,permanent},
{shutdown,5000},
{child_type,worker}]
