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From:Jonas Oreland Date:October 21 2011 7:22am
Subject:Re: Slow session (connection) set-up using MySQLD API
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On 10/21/11 08:55, Magnus Blåudd wrote:
> Hi,
>
> I remember that we had a similar problem with the 5.1 based MySQL Cluster - holding a
> mutex while doing network IO to release resources when the session disconnected. Problem
> was fixed with a custom patch and was supposed to be fixed in 5.5

if this patch never made it into 5.5...this could very well be the problem, yes

/Jonas

>
> / Magnus
>
> ----- Reply message -----
> From: "Jonas Oreland" <jonas.oreland@stripped>
> Date: Thu, Oct 20, 2011 21:41
> Subject: Slow session (connection) set-up using MySQLD API
> To: <paul@stripped>
> Cc: "Johan Andersson" <johan@stripped>,
> <cluster@stripped>
>
>
> On 10/20/11 21:37, Johan Andersson wrote:
>  > Hi Paul,
>  >
>  > Could you give an illustrative example of what the SELECT query looks like and
> what is the data model - roughly what the table(s) look like, and how it is indexed, and
> sizes, and if blobs/texts etc are used.
>  >
>  > I can try it then on my cluster.
>
> i'm also interested in what type of application it is...
>
> c program
> php
> perl
> something else cool
>
> /Jonas
>
>  >
>  > Best regards,
>  > johan
>  >
>  > On 2011-10-20 17.38, paul@stripped wrote:
>  >> Jonas,
>  >>
>  >> Attached are the config.ini file (for the management nodes), my.cnf file
>  >> (for the MySQLD API nodes, in this case for node 55), and the ndbd.cnf
>  >> file (for the data nodes).
>  >>
>  >> Unfortunately I am not allowed to share the source code of my test
>  >> program, I'm sorry.
>  >>
>  >> Thanks for your help, Paul
>  >>
>  >>> -------- Original Message --------
>  >>> Subject: Re: Slow session (connection) set-up using MySQLD API
>  >>> From: Jonas Oreland<jonas.oreland@stripped>
>  >>> Date: Thu, October 20, 2011 4:06 pm
>  >>> To:paul@stripped
>  >>> Cc:cluster@stripped
>  >>>
>  >>>
>  >>> On 10/20/11 15:31,paul@stripped wrote:
>  >>>> Hello,
>  >>>>
>  >>>> I'm evaluating MySQL Cluster as a replacement for our current
> "normal"
>  >>>> MySQL Server. The current server is processing many "update"
> queries per
>  >>>> second, sent by a client application that always stays connected to
> the
>  >>>> server. On the other hand, the server is serving "select" queries
> on the
>  >>>> same table, using clients that disconnect after each query (i.e.,
>  >>>> requests coming from a web server, without connection pooling).
>  >>>>
>  >>>> In my evaluation I have observed that MySQL Cluster with two data
> nodes
>  >>>> offers a superior "update" performance compared to a MySQL Server
>  >>>> instance running on identical hardware. However, performance for
> the
>  >>>> "select" queries is much worse on MySQL Cluster (using MYSQLD as
> API).
>  >>>>
>  >>>> Apparently MySQL Cluster has much more "overhead" setting up a
> session
>  >>>> (connection). The difference between MySQL Server and MySQL Cluster
> is
>  >>>> quite dramatic: In our test set-up MySQL Cluster could only server
> about
>  >>>> 65 connect-select-disconnect cycles, whereas MySQL Server can
> easily
>  >>>> handle 1000 and more cycles per second. This is quite a
> show-stopper for
>  >>>> our purposes...
>  >>>>
>  >>>> Note that all queries are done using the primary key, and all
> updates
>  >>>> and selects work on exactly one row. In total our test table
> contains
>  >>>> 100,000 rows. The MySQL Server version used to test was 5.1 and
> MySQL
>  >>>> Cluster was version 7.2.1 with MySQLD 5.5.
>  >>>>
>  >>>> Does anyone else has the same experience with MySQL Cluster? Is
> there
>  >>>> any way to improve this connect-select-disconnect cycles?
>  >>>>
>  >>>> Thanks for your help,
>  >>>>
>  >>>> Paul
>  >>> Hi Paul,
>  >>>
>  >>> Could you share your my.cnf and maybe your application (that does the
> SELECT) so
>  >>> I can test for my self ?
>  >>>
>  >>> /Jonas
>  >>>
>  >>>
>  >>>
>  >
>
>
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Thread
Slow session (connection) set-up using MySQLD APIpaul20 Oct
  • Re: Slow session (connection) set-up using MySQLD APIJohan Andersson20 Oct
  • Re: Slow session (connection) set-up using MySQLD APIJonas Oreland20 Oct
RE: Slow session (connection) set-up using MySQLD APIpaul20 Oct
RE: Slow session (connection) set-up using MySQLD APIpaul20 Oct
  • Re: Slow session (connection) set-up using MySQLD APIJohan Andersson20 Oct
    • Re: Slow session (connection) set-up using MySQLD APIJonas Oreland20 Oct
Re: Slow session (connection) set-up using MySQLD APIJonas Oreland21 Oct