Faster 'read_first_row' (Fixes slow 'preparing' state)
Read constant tables earlier, which provides better optimzations when using tables with <=1 row.
This also fixes a complicated bug involving const tables.


Docs/manual.texi:
  Changelog
client/mysql.cc:
  Increase max package length to 512M
client/mysqldump.c:
  Increase max package length to 512M
dbug/dbug.c:
  Fixed wrong printf() format string.
mysql-test/t/innodb.test:
  Test for multi-table delete
sql/handler.cc:
  Faster 'read_first_row' (Fixes slow 'preparing' state)
sql/handler.h:
  Faster 'read_first_row' (Fixes slow 'preparing' state)
sql/opt_range.cc:
  More debug info.
sql/sql_select.cc:
  Read constant tables earlier, which provides better optimzations when using tables with <=1 row.
  This also fixes a complicated bug involving const tables.
sql/sql_select.h:
  Read const tables earlier