Обсуждение: Regarding facing lot of time Consumed by Socket.Poll()

Hi ,

In my project I use Nhibernate to connect to Postgres.
Currently it is very slow.

I have used Yourkit profiller to get some key informaitons.
In CPU profilling i have analyzed following  things : -
Let me explain one by one : -

1- NHibernate.Impl.SessionImpl.DoLoad(Type, Object, Object, LockMode, Boolean)
 
Takes lots of time .

2- Internally it calls thse function i am listing the last stack

NpgsqlConnector.Open()
Npgsql.NpgsqlConnectedState.Startup(NpgsqlConnector)
Npgsql.NpgsqlState.ProcessBackendResponses(NpgsqlConnector)
[Wall Time]  System.Net.Sockets.Socket.Poll(Int32, SelectMode)

Finally in last the socket.poll takes most of the time .


I want to know the probably causes of the socket.poll() consumes allot of time .

Please help me out to know the places why in DoLoad,DoLoadByClass and Socket.Poll is taking lot of time .

What are the scenario in which it might be getting slow down , Which i need to look .


--
Thanks,
Keshav Upadhyaya

Thanks Matthew for your quick reply .
Let me make my self more clear.

Suppose  While doing one operation in my project,  total time taken is 41 min .

in this 41 min around 35 min is takne by this call --

NHibernate.Impl.SessionImpl.DoLoad(Type, Object, Object, LockMode, Boolean)
and DoLoadbyClass().

And i believe internally these calls used System.Net.Sockets.Socket.Poll(Int32, SelectMode)

Which take most of the time not a bit* time .

And when i Use MSSQL no such kind of polling happens and it work in aound 2-3 mins .

So i believe Nhibernate config filles or some other configuration w.r.t. Postgres  is not proper or improvement required.

Thanks,
keshav





--
Thanks,
Keshav Upadhyaya

Hi heikki,

First of all a big thanks for your reply .

From server side query are not taking much time I have checked that .

But from the client side when i am executing Nhibernate.doload() , doloadbyclass() functions
it is taking much of the CPU time .
This i have analyzed by YOURKIT profiler for .Net applications  .
Most of the CPU time is taken by Nhibernate.doload() , doloadbyclass() functions  and i believe internally they are
calling System.Net.Sockets.Socket.Poll(Int32, SelectMode) function .

So my big worry is why Nhibernate.DoLoad() , DoLoadByClass is taking much of the time ?
Is there any Nhibernate related config file  got changed ? or what are the most probale places for this problem so that i can look for them.


Apart from this i want to ask one more question .

In one machine it calls  NPGSQLconnectorpool.GetNonpooledConnector()
and in other machien  it callse  NPGSQLconnectorpool.GepooledConnector()

Does calling pool and nonpool version of methods make a big difference ?

Thanks ,
Keshav







--
Thanks,
Keshav Upadhyaya

On Thu, 15 Oct 2009, keshav upadhyaya wrote:
> [Wall Time]  System.Net.Sockets.Socket.Poll(Int32, SelectMode)

RTFM. Socket.Poll *waits* for a socket. Obviously it's going to spend
quite a bit of time.

Note that it is "wall time", not "CPU time".

You would be better investigating whatever is at the other end of the
socket, which I presume is Postgres. Look at what the queries actually
are, and try EXPLAIN ANALYSE on a few.

Matthew

--
 It is better to keep your mouth closed and let people think you are a fool
 than to open it and remove all doubt.                  -- Mark Twain

keshav upadhyaya wrote:
> 2- Internally it calls thse function i am listing the last stack
>
> NpgsqlConnector.Open()
> Npgsql.NpgsqlConnectedState.Startup(NpgsqlConnector)
> Npgsql.NpgsqlState.ProcessBackendResponses(NpgsqlConnector)
> *[Wall Time]  System.Net.Sockets.Socket.Poll(Int32, SelectMode)*
>
> Finally in last the socket.poll takes most of the time .
>
>
> I want to know the probably causes of the socket.poll() consumes allot of
> time .

I don't know much about Npgsql driver, but I'd guess that it's spending
a lot of time on Socket.Poll, because it's waiting for a response from
the server, sleeping. If you're investigating this because you feel that
queries are running too slowly, you should look at what the queries are
and investigate why they're slow in the server, e.g with EXPLAIN
ANALYZE. If you're investigating this because you're seeing high CPU
load in the client, try finding an option in the profiler to measure CPU
time, not Wall time.

--
  Heikki Linnakangas
  EnterpriseDB   http://www.enterprisedb.com

On Thu, Oct 15, 2009 at 10:02 AM, keshav upadhyaya
<ukeshav2009@gmail.com> wrote:
> Hi ,
>
> In my project I use Nhibernate to connect to Postgres.
> Currently it is very slow.
>
> I have used Yourkit profiller to get some key informaitons.
> In CPU profilling i have analyzed following  things : -
> Let me explain one by one : -
>
> 1- NHibernate.Impl.SessionImpl.DoLoad(Type, Object, Object, LockMode,
> Boolean)
>
> Takes lots of time .
>
> 2- Internally it calls thse function i am listing the last stack
>
> NpgsqlConnector.Open()
> Npgsql.NpgsqlConnectedState.Startup(NpgsqlConnector)
> Npgsql.NpgsqlState.ProcessBackendResponses(NpgsqlConnector)
> [Wall Time]  System.Net.Sockets.Socket.Poll(Int32, SelectMode)
>
> Finally in last the socket.poll takes most of the time .
>
>
> I want to know the probably causes of the socket.poll() consumes allot of
> time .
>
> Please help me out to know the places why in DoLoad,DoLoadByClass and
> Socket.Poll is taking lot of time .
>
> What are the scenario in which it might be getting slow down , Which i need
> to look .

I'm not sure that you're going to get too much help with this one on
this mailing list.  It's not really a PostgreSQL question.  You might
try the npgsql guys...

...Robert