cppcms-users

[Cppcms-users] How to reconnect to MySQL

[陈抒 <csf...@gm...>]

Hello,
  My web site's DB connection broke because of timeout. My web site is
developed in China,but MySQL server is running in the USA. I got one error
log:
2011-12-05 15:43:02 GMT; cppcms, error: Caught exception
[cppdb::mysql::Lost connection to MySQL server during query]
 (http_context.cpp:150)

  I have used reconnect property already:
    stringstream stream;

stream<<"mysql:host="<<config.mysql_ip<<";database="<<config.mysql_db_name<<";user="<<config.mysql_user<<";password="<<config.mysql_password<<";@pool_size=20;set_charset_name=utf8;
opt_reconnect=1";

  But it didn't work. How should I do? Catch exception and call
cppdb::connections_manager::gc() ?


陈抒
Best regards
http://blog.csdn.net/sheismylife

Re: [Cppcms-users] How to reconnect to MySQL

[Artyom B. <art...@ya...>]

Hello,


I had checked it and yes indeed, there is a problem.

The opt_reconnect does not work as prepared statements do not survive connection lost.

It works with @use_prepared=off and opt_reconnect=1 but of course it has performance
penalty as you loose all advantages of CppDB prepared statements caching.

If the connection is lost due to timeout then probably you can change @pool_max_idle
to smaller value (default is 600 i.e. 10 minutes)


>

> But it didn't work. How should I do? Catch exception
> and call cppdb::connections_manager::gc() ?
>


Currently this is only option that works.

Also notice that you need to call it **after** connection is closed:

   try {
      cppdb::session sql(...)

   }catch(cppdb::cppdb_error const &) {
      cppdb::connections_manager::instance().gc();
      throw;

   }

I'll look on it deeply ASAP, but it is not something simple to fix.

I had opened a ticket: 


   https://sourceforge.net/tracker/?func=detail&aid=3451653&group_id=209965&atid=1011835


Artyom Beilis
--------------
CppCMS - C++ Web Framework:   http://cppcms.sf.net/
CppDB - C++ SQL Connectivity: http://cppcms.sf.net/sql/cppdb/


>________________________________
> From: 陈抒 <csf...@gm...>
> 
>
>Hello,
>  My web site's DB connection broke because of timeout. My web site is developed in China,but MySQL server is running in the USA. I got one error log:
>2011-12-05 15:43:02 GMT; cppcms, error: Caught exception [cppdb::mysql::Lost connection to MySQL server during query]
> (http_context.cpp:150)
>
>
>  I have used reconnect property already:
>    stringstream stream;
>    stream<<"mysql:host="<<config.mysql_ip<<";database="<<config.mysql_db_name<<";user="<<config.mysql_user<<";password="<<config.mysql_password<<";@pool_size=20;set_charset_name=utf8;opt_reconnect=1";
>
>
>
>陈抒 
>Best regards
>http://blog.csdn.net/sheismylife
>
>------------------------------------------------------------------------------
>All the data continuously generated in your IT infrastructure 
>contains a definitive record of customers, application performance, 
>security threats, fraudulent activity, and more. Splunk takes this 
>data and makes sense of it. IT sense. And common sense.
>http://p.sf.net/sfu/splunk-novd2d
>_______________________________________________
>Cppcms-users mailing list
>Cpp...@li...
>https://lists.sourceforge.net/lists/listinfo/cppcms-users
>
>
> 

Re: [Cppcms-users] How to reconnect to MySQL

[Artyom B. <art...@ya...>]

> 

> The opt_reconnect does not work as prepared statements do not survive connection 
> lost.
> 

Another possible way to solve this problem is to clear prepared statements cache
in case of error.

    cppdb::session sql(...)
    try {
      sql << ... 
    }catch(cppdb::cppdb_error const &) {
       sql.clear_cache();
       throw;
    }

This would work with opt_reconnect=1, but yet it is a workaround.

Artyom

Re: [Cppcms-users] How to reconnect to MySQL

[Artyom B. <art...@ya...>]

Fixed in trunk of cppdb. Now if exception is thrown during use of a connection
the connection is not recycled.

 
Artyom Beilis
--------------
CppCMS - C++ Web Framework:   http://cppcms.sf.net/
CppDB - C++ SQL Connectivity: http://cppcms.sf.net/sql/cppdb/


>________________________________
> From: 陈抒 <csf...@gm...>
>To: cpp...@li... 
>Sent: Monday, December 5, 2011 6:03 PM
>Subject: [Cppcms-users] How to reconnect to MySQL
> 
>
>Hello,
>  My web site's DB connection broke because of timeout. My web site is developed in China,but MySQL server is running in the USA. I got one error log:
>2011-12-05 15:43:02 GMT; cppcms, error: Caught exception [cppdb::mysql::Lost connection to MySQL server during query]
> (http_context.cpp:150)
>
>
>  I have used reconnect property already:
>    stringstream stream;
>    stream<<"mysql:host="<<config.mysql_ip<<";database="<<config.mysql_db_name<<";user="<<config.mysql_user<<";password="<<config.mysql_password<<";@pool_size=20;set_charset_name=utf8;opt_reconnect=1";
>
>
>  But it didn't work. How should I do? Catch exception and call cppdb::connections_manager::gc() ?
>
>
>陈抒 
>Best regards
>http://blog.csdn.net/sheismylife
>
>------------------------------------------------------------------------------
>All the data continuously generated in your IT infrastructure 
>contains a definitive record of customers, application performance, 
>security threats, fraudulent activity, and more. Splunk takes this 
>data and makes sense of it. IT sense. And common sense.
>http://p.sf.net/sfu/splunk-novd2d
>_______________________________________________
>Cppcms-users mailing list
>Cpp...@li...
>https://lists.sourceforge.net/lists/listinfo/cppcms-users
>
>
>

Re: [Cppcms-users] How to reconnect to MySQL

[陈抒 <csf...@gm...>]

Thanks.

陈抒
Best regards
http://blog.csdn.net/sheismylife


On Thu, Dec 22, 2011 at 6:49 AM, Artyom Beilis <art...@ya...> wrote:

> Fixed in trunk of cppdb. Now if exception is thrown during use of a
> connection
> the connection is not recycled.
>
> Artyom Beilis
> --------------
> CppCMS - C++ Web Framework: http://cppcms.sf.net/
> CppDB - C++ SQL Connectivity: http://cppcms.sf.net/sql/cppdb/
>
>   ------------------------------
> *From:* 陈抒 <csf...@gm...>
> *To:* cpp...@li...
> *Sent:* Monday, December 5, 2011 6:03 PM
> *Subject:* [Cppcms-users] How to reconnect to MySQL
>
> Hello,
>   My web site's DB connection broke because of timeout. My web site is
> developed in China,but MySQL server is running in the USA. I got one error
> log:
> 2011-12-05 15:43:02 GMT; cppcms, error: Caught exception
> [cppdb::mysql::Lost connection to MySQL server during query]
>  (http_context.cpp:150)
>
>   I have used reconnect property already:
>     stringstream stream;
>
> stream<<"mysql:host="<<config.mysql_ip<<";database="<<config.mysql_db_name<<";user="<<config.mysql_user<<";password="<<config.mysql_password<<";@pool_size=20;set_charset_name=utf8;
> opt_reconnect=1";
>
>   But it didn't work. How should I do? Catch exception and call
> cppdb::connections_manager::gc() ?
>
>
> 陈抒
> Best regards
> http://blog.csdn.net/sheismylife
>
>
> ------------------------------------------------------------------------------
> All the data continuously generated in your IT infrastructure
> contains a definitive record of customers, application performance,
> security threats, fraudulent activity, and more. Splunk takes this
> data and makes sense of it. IT sense. And common sense.
> http://p.sf.net/sfu/splunk-novd2d
> _______________________________________________
> Cppcms-users mailing list
> Cpp...@li...
> https://lists.sourceforge.net/lists/listinfo/cppcms-users
>
>
>
>
> ------------------------------------------------------------------------------
> Write once. Port to many.
> Get the SDK and tools to simplify cross-platform app development. Create
> new or port existing apps to sell to consumers worldwide. Explore the
> Intel AppUpSM program developer opportunity. appdeveloper.intel.com/join
> http://p.sf.net/sfu/intel-appdev
> _______________________________________________
> Cppcms-users mailing list
> Cpp...@li...
> https://lists.sourceforge.net/lists/listinfo/cppcms-users
>
>