The optimizer takes different execution paths during EXPLAIN than SELECT,
this fix relates only to EXPLAIN, hence no behavior changes.
The test of sort keys for ORDER BY was prohibited from considering keys
that were mentioned in IGNORE KEYS FOR ORDER BY. This led to two 
inconsistencies: One was that IGNORE INDEX FOR GROUP BY and 
IGNORE INDEX FOR ORDER BY gave apparently different EXPLAINs; the latter 
erroneously claimed to do filesort. The second inconsistency 
is that the test of sort keys is called twice, finding a sort key the first
time but not the second time, leading to the mentioned filesort.

Fixed by making the test of sort keys consider all enabled 
keys on the table. This test rejects keys that are not covering, and for 
covering keys the hint should be ignored anyway. 

into  mysql.com:/home/gluh/MySQL/Merge/5.1-opt

into  mysql.com:/home/gluh/MySQL/Merge/5.1-opt

into  mysql.com:/home/gluh/MySQL/Merge/5.1-opt

added get_field_default_value() function which obtains default value from the field
(used in store_create_info() & get_schema_column_record() functions)

into  magare.gmz:/home/kgeorge/mysql/autopush/B30639-5.1-opt

 The parser uses ulonglong to store the LIMIT number. This number
 then is stored into a variable of type ha_rows. ha_rows is either
 4 or 8 byte depending on the BIG_TABLES define from config.h
 So an overflow may occur (and LIMIT becomes zero) while storing an
 ulonglong value in ha_rows.
 Fixed by :
  1. Using the maximum possible value for ha_rows on overflow
  2. Defining BIG_TABLES for the windows builds (to match the others) 

into  mysql.com:/home/gluh/MySQL/Merge/5.1-opt

into  mysql.com:/home/gluh/MySQL/Merge/5.1-opt

into  mysql.com:/home/gluh/MySQL/Merge/5.0-opt

  Post-merge fix.

into  devsrv-b.mysql.com:/data0/gshchepa/mysql-5.1-opt

  Post-fix for bug#27695.

into  magare.gmz:/home/kgeorge/mysql/autopush/B31001-5.1-opt

into  devsrv-b.mysql.com:/data0/gshchepa/mysql-5.1-opt

into  devsrv-b.mysql.com:/data0/gshchepa/mysql-5.0-opt

into  magare.gmz:/home/kgeorge/mysql/autopush/B31001-5.0-opt

into  magare.gmz:/home/kgeorge/mysql/work/B31001-5.1-opt

  Merge with 5.0-opt.

The optimizer sets index traversal in reverse order only if there are 
 used key parts that are not compared to a constant.
However using the primary key as an ORDER BY suffix rendered the check
incomplete : going in reverse order must still be used even if 
all the parts of the secondary key are compared to a constant.

Fixed by relaxing the check and set reverse traversal even when all
the secondary index keyparts are compared to a const.
Also account for the case when all the primary keys are compared to a
constant.

into  mysql.com:/home/psergey/mysql-5.1-bug27927

into  mysql.com:/home/psergey/mysql-5.0-bug30324

- The bug was caused by COUNT(DISTINCT ...) code using Unique object in 
  a way that assumed that BIT(N) column occupies a contiguous space in
  temp_table->record[0] buffer. 
- The fix is to make COUNT(DISTINCT ...) code instruct create_tmp_table to
  create temporary table with column of type BIGINT, not BIT(N).

into  mysql.com:/home/psergey/mysql-5.1-bug27927

- Introduced val_int_endpoint() function which converts between func 
  argument intervals and func value intervals for monotonic functions.
- Made partition interval analyzer use part_expr->val_int_endpoint()
  to check if the edge values should be included.

into  whalegate.ndb.mysql.com:/home/tomas/mysql-5.1-new-ndb-merge

into  whalegate.ndb.mysql.com:/home/tomas/mysql-5.1-new-ndb-merge

into  whalegate.ndb.mysql.com:/home/tomas/mysql-5.0-ndb-merge

into  whalegate.ndb.mysql.com:/home/tomas/mysql-5.0-ndb-merge

into  whalegate.ndb.mysql.com:/home/tomas/mysql-5.1-new-ndb

into  devsrv-b.mysql.com:/data0/gshchepa/mysql-5.1-opt

into  devsrv-b.mysql.com:/data0/gshchepa/mysql-5.0-opt

into  gleb.loc:/home/uchum/work/bk/5.0-opt-27695

into  gleb.loc:/home/uchum/work/bk/5.1-opt

into  gleb.loc:/home/uchum/work/bk/5.1-opt