a worse execution plan than in 4.1 for some queries.
It happened due the fact that at some conditions the 
optimizer always preferred range or full index scan access
methods to lookup access methods even when the latter were much
cheaper. 
The problem was not observed in 4.1 for the reported query
because the WHERE condition was not of a form that could
cause the problem.
Equality propagation introduced on 5.0 added an extra 
predicate and changed the WHERE condition. The new condition
provoked the optimizer to make a bad choice.

The problem was fixed by the patch for bug 17379.


mysql-test/r/select.result:
  Added a test case for bug #18940.
  The problem was fixed by the patch for bug 17379.
mysql-test/t/select.test:
  Added a test case for bug #18940.
  The problem was fixed by the patch for bug 17379.

into  zippy.(none):/home/cmiller/work/mysql/mysql-5.0-maint


client/mysql.cc:
  Auto merged

into  mysql.com:/home/mysql-5.0-19263

  Compile in all character sets in Max (bug#14918)


support-files/mysql.spec.sh:
  Compile in all character sets in Max (bug#14918)

into  production.mysql.com:/usersnfs/rkalimullin/mysql-5.0

into  production.mysql.com:/usersnfs/rkalimullin/mysql-5.0

into  zippy.(none):/home/cmiller/mysql-5.0__bug19564

Re-work best_access_path() and find_best() to reuse E(#rows(range access)) as
E(#rows(ref[_or_null](const) access) only when it is appropriate.
[This is the final cumulative patch]


mysql-test/r/select.result:
  BUG#17379: Testcase
mysql-test/r/subselect.result:
  BUG#17379: Updated test results
mysql-test/t/select.test:
  BUG#17379: Testcase
sql/opt_range.cc:
  BUG#17379: Wrong reuse of E(#rows(range)) as E(#rows(ref(const))):
  Make range optimizer together with TABLE::quick_* also return TABLE::quick_n_ranges
sql/sql_select.cc:
  BUG#17379: Wrong reuse of E(#rows(range)) as E(#rows(ref(const))):
  Re-work best_access_path() to reuse E(#rows(range access)) as
  E(#rows(ref[_or_null](const) access) only when it is appropriate.
sql/table.h:
  BUG#17379: Wrong reuse of E(#rows(range)) as E(#rows(ref(const))):
  Make range optimizer together with TABLE::quick_* also return TABLE::quick_n_ranges

into  mysql.com:/usr/home/ram/work/mysql-5.0


sql/item_timefunc.cc:
  Auto merged
mysql-test/r/func_time.result:
  merging
mysql-test/t/func_time.test:
  merging

into  zippy.(none):/home/cmiller/mysql-5.0__bug19564

into  mysql.com:/usr/home/ram/work/4.1.b18501


sql/item_timefunc.cc:
  Auto merged

into  mysql.com:/home/kgeorge/mysql/5.0/B18068


sql/sql_select.cc:
  Auto merged

Correct a bug (that I introduced, after using Oracle's database software for 
too many years) where the length of the database-sent data is incorrectly 
used to infer NULLness.


client/mysql.cc:
  No longer use the length of the data to infer whether it is NULL or not.
mysql-test/r/mysql.result:
  Add result and version marker, and correct previous result.
mysql-test/t/mysql.test:
  Add test and version marker

into  mysql.com:/home/psergey/mysql-5.0-best_access_path_j-push

into  mysql.com:/home/psergey/mysql-5.0-best_access_path_j-push


sql/sql_select.cc:
  Auto merged

into  xiphis.org:/home/antony/work2/mysql-5.0-engines-merge

into  xiphis.org:/home/antony/work2/p1-bug10952.1


sql/handler.h:
  Auto merged
sql/sql_table.cc:
  Auto merged

  "alter table from MyISAM to MERGE lost data without errors and warnings"
  Add new handlerton flag which prevent user from altering table storage
  engine to storage engines which would lose data. Both 'blackhole' and 
  'merge' are marked with the new flag.
  Tests included.


mysql-test/r/blackhole.result:
  test for bug#10952
mysql-test/r/merge.result:
  test for bug#10952
mysql-test/t/blackhole.test:
  test for bug#10952
mysql-test/t/merge.test:
  test for bug#10952
sql/ha_blackhole.cc:
  Bug#10952
    shouldn't be able to alter a table into a blackhole
sql/ha_myisammrg.cc:
  Bug#10952
    shouldn't be able to alter a table into a merge
sql/handler.h:
  Bug#10952
    new handlerton flag
sql/sql_table.cc:
  Bug#10952
    If alter is changing engine, check if new engine allows creating table
    via ALTER statement.

When converting DISTINCT to GROUP BY where the columns are from the covering
index and they are quoted twice in the SELECT list the optimizer is creating
improper processing sequence. This is because of the fact that the columns
of the covering index are not recognized as such and treated as non-index
columns.

Generally speaking duplicate columns can safely be removed from the GROUP
BY/DISTINCT list because this will not add or remove new rows in the
resulting set. Duplicates can be removed even if they are not consecutive
(as is the case for ORDER BY, where the duplicate columns can be removed
only if they are consecutive).

So we can safely transform "SELECT DISTINCT a,a FROM ... ORDER BY a" to
"SELECT a,a FROM ... GROUP BY a ORDER BY a" instead of 
"SELECT a,a FROM .. GROUP BY a,a ORDER BY a". We can even transform 
"SELECT DISTINCT a,b,a FROM ... ORDER BY a,b" to
"SELECT a,b,a FROM ... GROUP BY a,b ORDER BY a,b".

The fix to this bug consists of checking for duplicate columns in the SELECT
list when constructing the GROUP BY list in transforming DISTINCT to GROUP
BY and skipping the ones that are already in.


mysql-test/r/distinct.result:
  test case for the bug without loose index scan
mysql-test/r/group_min_max.result:
  test case for the bug
mysql-test/t/distinct.test:
  test case for the bug without loose index scan
mysql-test/t/group_min_max.test:
  test case for the bug
sql/sql_select.cc:
  duplicates check and removal

into  neptunus.(none):/home/msvensson/mysql/mysql-5.0-maint

into  neptunus.(none):/home/msvensson/mysql/mysql-5.0-maint

into  mysql.com:/home/marty/MySQL/mysql-5.0

into  mysql.com:/home/marty/MySQL/mysql-5.0


ndb/src/kernel/blocks/dbtc/DbtcInit.cpp:
  Auto merged

 - Add a check to see if the .mysql_history file a symlink to /dev/null 
   and in such case, skip reading and writing to it. 
     


client/mysql.cc:
  Add check to detect if the "mysql_history" file is a symlink to /dev/null.
  In that case, don't create histfile variable.
  That will make read_history and write_history to be skipped.

into  neptunus.(none):/home/msvensson/mysql/mysql-5.0


sql/item_func.cc:
  Auto merged
sql/sql_acl.cc:
  Auto merged

into  neptunus.(none):/home/msvensson/mysql/mysql-5.0-maint


client/mysqltest.c:
  Auto merged
mysql-test/mysql-test-run.pl:
  Auto merged
sql/mysql_priv.h:
  Auto merged

No commit message

into mysql.com:/Users/kent/mysql/bk/mysql-5.0-new


configure.in:
  Auto merged

Add function 'vio_end' that will cleanup resources allocated by vio and the components it uses.


include/violite.h:
  Import patch warnings.patch
libmysql/libmysql.c:
  Import patch warnings.patch
sql/mysqld.cc:
  Import patch warnings.patch
vio/test-ssl.c:
  Import patch warnings.patch
vio/test-sslclient.c:
  Import patch warnings.patch
vio/test-sslserver.c:
  Import patch warnings.patch
vio/vio.c:
  Import patch warnings.patch
vio/viosslfactories.c:
  Import patch warnings.patch

into  neptunus.(none):/home/msvensson/mysql/mysql-5.0-maint

into  neptunus.(none):/home/msvensson/mysql/mysql-5.0-maint


extra/yassl/src/ssl.cpp:
  Auto merged
extra/yassl/taocrypt/src/make.bat:
  Auto merged
extra/yassl/testsuite/test.hpp:
  Auto merged

save global server variables before fiddling with them and restore them later


BitKeeper/deleted/.del-variables-master.opt~8a6cb6459b54545:
  Delete: mysql-test/t/variables-master.opt
mysql-test/r/variables.result:
  save and restore globals
mysql-test/t/variables.test:
  save and restore globals

into  rurik.mysql.com:/home/igor/mysql-5.0


mysql-test/r/rpl_user_variables.result:
  Auto merged
sql/item_func.cc:
  Auto merged
sql/sql_select.cc:
  Auto merged
mysql-test/t/rpl_user_variables.test:
  Manual merge

into  rurik.mysql.com:/home/igor/dev/mysql-5.0-0


mysql-test/r/having.result:
  Auto merged
mysql-test/t/having.test:
  Auto merged
sql/item_func.cc:
  Auto merged
sql/sql_lex.h:
  Auto merged
mysql-test/r/rpl_user_variables.result:
  Manual merge
mysql-test/t/rpl_user_variables.test:
  Manual merge
sql/sql_lex.cc:
  Manual merge
sql/sql_prepare.cc:
  Manual merge
sql/sql_select.cc:
  Manual merge

into  rurik.mysql.com:/home/igor/mysql-4.1

into  mysql.com:/usr_rh9/home/elkin.rh9/MySQL/Merge/5.0-bug19136


sql/sql_select.cc:
  Auto merged

recalculating results


mysql-test/r/rpl_user_variables.result:
  fixing results