Last time I came up with a problem with concernin MySQL authorization with stored procedures. Timo helped me get going by with modified client_flags (MULTISTATEMENT keyword).

Now all it happened again but from another way. My stored proce for MySQL is causing fillowing error:

"Oct 21 12:39:22 haos dovecot: auth-worker(default): sql(user,192.168.X.X): Password query fai led: Commands out of sync; you can't run this command now"

Looks like it is partly mysql-5.0.26 thing because of this:  http://dev.mysql.com/doc/refman/5.0/en/commands-out-of-sync.html

On the other hand with my previous mysql installation (mysql-5.0.24-r1 ) this error is gone (I checked by downgrading).
My dovecot-sql.conf:

driver = mysql
connect = host=/var/run/mysqld/mysqld.sock dbname=mailbase user=mailuser password=******** client_flags=65536
#655536 is equivalent of CLIENT_MULTI_STATEMENTS flag
#yes, I still insist on using stored proc for authorization. This gives me few usefull features I like.
password_query = call Authenticat('%u', '%n', '%d')

With this config on mysq-5.0.26 I get
"...Commands out of sync; you can't run this command now..."
but not on mysql-5.0.24-r1.
Personally I think mysql guys changed something; I can't tell what and why (changelog review?)
Maybe you guys know what it was?

--
Chaos greets U