* Fixed a problem with wrong query results for partially covering keys in ROR-index_merge
 * ROR-intersection retrieval plan choice algorithm now uses less disk IO
   - and properly processes clustered PK range scans 
 * Fixed several minor range optimizer problems
 * Added more comments
 * Code cleanup

This is first cset for WL#1394 "Optimize index merge when all involved index ranges include only values with equal keys"
The main idea is to exploit the fact that key scans for "key=const" return ordered sequences of rowids.

into sanja.is.com.ua:/home/bell/mysql/bk/work-parser-5.0

consisting of pos-review fixes and improvements.

statements.

merged manually by guilhem.

into sanja.is.com.ua:/home/bell/mysql/bk/work-ps3-4.1

into eagle.mysql.r18.ru:/home/vva/work/BUG_3342/mysql-4.1

Fixed problems with group_concat() and HAVING
Updated crash-me values

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

bug #3342 "SHOW CREATE DATABASE seems to require DROP privilege"
(now it require only SELECT privilege on database)

if doesn't exists or is not writable, then /var/log/mysqld_multi.log, if does not exists
or is not writable, then /tmp/mysqld_multi.log, but only in case the file does not yet
exists in /tmp. Otherwise log will be disabled, unless user explicitely sets it with an
option.

Actually catch pushed warnings.

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

into serg.mylan:/usr/home/serg/Abk/mysql-4.1

for Bug #2385 CREATE TABLE LIKE lacks locking on source and destination table

Keep track on the default value and use it. (Or NULL, if not declared.)

Complex return types were not stored correctly in the mysql.proc table.

into serg.mylan:/usr/home/serg/Abk/mysql-4.1

into serg.mylan:/usr/home/serg/Abk/mysql-4.1

Here is 2nd version.
'reduce/reduce conflicts' issue is fixed

Don't add -debug to server version if MYSQL_SERVER_PREFIX is used
Indentation cleanups

Backpatching overwrote already backpatched instructions, which made it
skip the hpop instruction; possibly not only a problem for handlers,
but this is one known case when it happened.

into gluh.mysql.r18.ru:/home/gluh/mysql-4.1.curr

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

the code.

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