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.
> 
>   sql/ha_federated.cc@stripped, 2007-07-09 21:54:03-07:00, antony@stripped +136 -156
>     bug25679
>       remove function check_foreign_data_source()
>       ha_federated::open() no longer opens the federated connection.
>       ha_federated::create() no longer opens and tests connection.
>       ha_federated::real_query() opens and tests presence of table.

Uhm, I don't know.

We have enough troubles with MERGE tables that don't check the
correctness until the first SELECT.

I personally would be ok with such a behaviour, but apparently many
users aren't, and I think it'd be unwise to implement this unpopular
approach.

Regards / Mit vielen Grüssen,
Sergei

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