After merge fix

into  mysql.com:/home/mydev/mysql-4.1-4100

The problem was an ab-use of last_rkey_length.
Formerly we saved the packed key length (of the search key)
in this element. But in certain cases it got replaced by 
the (packed) result key length.
Now we use a new element of MI_INFO to save the packed key 
length of the search key.

into  mysql.com:/usr/home/ram/work/4.1.b11553

into mysql.com:/home/gluh/MySQL/Merge/4.1

  set auto_increment_field_not_null to true to preserve zero values
  for autoincrement fields during LOAD DATA execution if 
  NO_AUTO_VALUE_ON_ZERO sql mode is set

into  perch.ndb.mysql.com:/home/jonas/src/mysql-4.1-push

  ndb big alter table

into  mysql.com:/usr/home/ram/work/4.1.b11553

  ndb alter table with big dicttabinfo
  send alter_tab_req fragmented as signal can get larger than MAX_MESSAGE_SIZE

into  perch.ndb.mysql.com:/home/jonas/src/mysql-4.1-push

into  perch.ndb.mysql.com:/home/jonas/src/mysql-4.1-push

into  mysql.com:/home/jimw/my/mysql-4.1-clean

into  mysql.com:/home/jimw/my/mysql-4.1-clean

into moonbone.local:/work/13180-bug-4.1-mysql

thd->allow_sum_func was left 'true' after previous statement thus allowing
sum funcs to be present in conditions.

thd->allow_sum_func should be set to 0 for each query and each prepared
statement reinitialization. This is done in lex_start() and 
reset_stmt_for_execute().

into  mysql.com:/home/timka/mysql/src/4.1-dbg

into  perch.ndb.mysql.com:/home/jonas/src/mysql-4.1-push

    ndb backup with charsets and simultanious updates
    make sure that backup _dont_ read xfrm data

into  perch.ndb.mysql.com:/home/jonas/src/mysql-4.1-push

into  mysql.com:/usr/home/ram/work/4.1.b7589

into  mysql.com:/home/timka/mysql/src/4.1-dbg

The problem was in that the MIN/MAX optimization in opt_sum_query was
replacing MIN/MAX functions with their constant argument without
taking into account that a query has no result rows.

into mysql.com:/home/psergey/mysql-4.1-csc6030-r3

statistics (like 4.0 did) (patch #3, with review #1 & #2 feedback addressed)

into  selena.:H:/MYSQL/src/#12929-mysql-4.1

into  perch.ndb.mysql.com:/home/jonas/src/mysql-4.1-push

into  perch.ndb.mysql.com:/home/jonas/src/mysql-4.1-push

into  perch.ndb.mysql.com:/home/jonas/src/mysql-4.1-push

into  asksasha.com:/reiser-data/mysql-dev/mysql-4.1-bug11139

into moonbone.local:/work/13218-bug-4.1-mysql

into  a193-229-222-105.elisa-laajakaista.fi:/home/my/bk/mysql-4.1