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

[Sergei Golubchik]

Hi!

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.

ok to push
before pushing please
1. answer the question below
2. move the everything inside if(!mysql) in real_query()
   to a separate function (e.g. real_connect())
3. submit a bugreport that federated (as a result of fix for bug#25679)
   doesn't connect and check the existance of the remote table on CREATE -
   it'll be set to "to be fixed later", but let's have it recorded in
   bugdb.
 
> 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 ? 

> +      DBUG_RETURN(-1);
> +    }
> +    

Regards / Mit vielen Grüssen,
Sergei

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