Re: bk commit into 5.0 tree (antony:1.2511) BUG#25679

[Sergei Golubchik]

Hi!

On Jul 24, Antony T Curtis wrote:
> On Tue, 2007-07-24 at 19:15 +0200, Sergei Golubchik wrote:
> > On Jul 09, antony@stripped wrote:
> > > ChangeSet@stripped, 2007-07-09 21:54:16-07:00, antony@stripped +4 -0
> > >   Bug#25679
> > >     "Federated Denial of Service"
> > >     Federated storage engine used to attempt to open connections within
> > >     the ::create() and ::open() methods which are invoked while LOCK_open
> > >     mutex is being held by mysqld. As a result, no other connection can
> > >     open tables during the network processing. Long DNS lookup times
> > >     would stall mysqld's operation and a rogue connection string which
> > >     connects to a remote server which simply stalls during handshake can
> > >     stall mysqld for much longer periods of time.
> > >     This patch moves the connection-opening much later to when LOCK_open
> > >     mutex is not being held.
> > 
> > > diff -Nrup a/sql/ha_federated.cc b/sql/ha_federated.cc
> > > --- a/sql/ha_federated.cc	2007-06-29 15:14:00 -07:00
> > > +++ b/sql/ha_federated.cc	2007-07-09 21:54:03 -07:00
> > ....
> > > +    if (!mysql_real_connect(mysql,
> > > +                            share->hostname,
> > > +                            share->username,
> > > +                            share->password,
> > > +                            share->database,
> > > +                            share->port,
> > > +                            share->socket, 0))
> > > +    {
> > > +      mysql_close(mysql);
> > > +      mysql= NULL;
> > > +      sql_query.append("database: '");
> > > +      sql_query.append(share->database);
> > > +      sql_query.append("'  username: '");
> > > +      sql_query.append(share->username);
> > > +      sql_query.append("'  hostname: '");
> > > +      sql_query.append(share->hostname);
> > > +      sql_query.append("'");
> > > +      my_error(ER_CONNECT_TO_FOREIGN_DATA_SOURCE, MYF(0),
> sql_query.ptr());
> > > +      remote_error_number= -1;
> > 
> > Why you don't use stash_remote_error(), but generates less informative
> > generic error message ? 
> 
> Using same error message as it used to generate in case where connection
> has failed.

But there was stash_remote_error() in ha_federated::open() before.
 
Regards / Mit vielen Grüssen,
Sergei

-- 
   __  ___     ___ ____  __
  /  |/  /_ __/ __/ __ \/ /   Sergei Golubchik <serg@stripped>
 / /|_/ / // /\ \/ /_/ / /__  Principal Software Developer
/_/  /_/\_, /___/\___\_\___/  MySQL GmbH, Radlkoferstr. 2, D-81373 München
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