into  adventure.(none):/home/thek/Development/cpp/bug27792/my51-bug27792

into  adventure.(none):/home/thek/Development/cpp/bug27792/my50-bug27792

 - Queries in the query cache are identified by the individual 
   characters in the query statement, the current database and 
   the current environment expressed as a set of system variable
   flags.
 - Since the set of environment flags didn't properly describe the
   current environment unexpected results were returned from the 
   query cache.
 - Query cache is now cleared when the variable ft_boolean_syntax is 
   updated.
 - An identification flag for the variable default_week_format is 
   added to the query cache record.
 
Thanks to Martin Friebe who has supplied significant parts of this patch.

into  weblab.(none):/home/marcsql/TREE/mysql-5.1-21513

Before this fix, the parser would sometime change where a token starts by
altering Lex_input_string::tok_start, which later confused the code in
sql_yacc.yy that needs to capture the source code of a SQL statement,
like to represent the body of a stored procedure.

This line of code in sql_lex.cc :

case MY_LEX_USER_VARIABLE_DELIMITER:
  lip->tok_start= lip->ptr; // Skip first `

would <skip the first back quote> ... and cause the bug reported.

In general, the responsibility of sql_lex.cc is to *find* where token are
in the SQL text, but is *not* to make up fake or incomplete tokens.
With a quoted label like `my_label`, the token starts on the first quote.
Extracting the token value should not change that (it did).

With this fix, the lexical analysis has been cleaned up to not change
lip->tok_start (in the case found for this bug).

The functions get_token() and get_quoted_token() now have an extra
parameters, used when some characters from the beginning of the token need
to be skipped when extracting a token value, like when extracting 'AB' from
'0xAB', for example, for a HEX_NUM token.

This exposed a bad assumption in Item_hex_string and Item_bin_string,
which has been fixed:

The assumption was that the string given, 'AB', was in fact preceded in
memory by '0x', which might be false (it can be preceded by "x'" and
followed by "'" -- or not be preceded by valid memory at all)

If a name is needed for Item_hex_string or Item_bin_string, the name is
taken from the original and true source code ('0xAB'), and assigned in
the select_item rule, instead of relying on assumptions related to how
memory is used.

into  weblab.(none):/home/marcsql/TREE/mysql-5.1-25411_merge

into  weblab.(none):/home/marcsql/TREE/mysql-5.0-25411_d

The issue found with bug 25411 is due to the function skip_rear_comments()
which damages the source code while implementing a work around.
The root cause of the problem is in the lexical analyser, which does not
process special comments properly.
For special comments like :
[1] aaa /*!50000 bbb */ ccc
since 5.0 is a version older that the current code, the parser is in lining
the content of the special comment, so that the query to process is
[2] aaa bbb ccc
However, the text of the query captured when processing a stored procedure,
stored function or trigger (or event in 5.1), can be after rebuilding it:
[3] aaa bbb */ ccc
which is wrong.

To fix bug 25411 properly, the lexical analyser needs to return [2] when
in lining special comments.
In order to implement this, some preliminary cleanup is required in the code,
which is implemented by this patch.

Before this change, the structure named LEX (or st_lex) contains attributes
that belong to lexical analysis, as well as attributes that represents the
abstract syntax tree (AST) of a statement.
Creating a new LEX structure for each statements (which makes sense for the
AST part) also re-initialized the lexical analysis phase each time, which
is conceptually wrong.

With this patch, the previous st_lex structure has been split in two:
- st_lex represents the Abstract Syntax Tree for a statement. The name "lex"
has not been changed to avoid a bigger impact in the code base.
- class lex_input_stream represents the internal state of the lexical
  analyser, which by definition should *not* be reinitialized when parsing
  multiple statements from the same input stream.

This change is a pre-requisite for bug 25411, since the implementation of
lex_input_stream will later improve to deal properly with special comments,
and this processing can not be done with the current implementation of
sp_head::reset_lex and sp_head::restore_lex, which interfere with the lexer.

This change set alone does not fix bug 25411.

into  blade09.mysql.com:/tmp/mmj/mysql-5.0-runtime

into  blade09.mysql.com:/tmp/mmj/mysql-5.1-runtime

into  mysql.com:/d2/hf/mrg/mysql-5.1-opt

into  bk-internal.mysql.com:/data0/bk/mysql-5.1-opt

into  bk-internal.mysql.com:/data0/bk/mysql-5.0-opt

into  weblab.(none):/home/marcsql/TREE/mysql-5.0-rt-merge

into  weblab.(none):/home/marcsql/TREE/mysql-5.1-rt-merge

into  moonbone.local:/mnt/gentoo64/work/bk-trees/mysql-5.1-opt

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

into  gshchepa.loc:/home/uchum/work/bk-trees/mysql-5.0-opt-27704

into  gshchepa.loc:/home/uchum/work/bk-trees/mysql-5.0-opt-27704

Support for NULL components was incomplete for row comparison,
fixed.  Added support for abort_on_null at compare_row() like
in 5.x

into  magare.gmz:/home/kgeorge/mysql/autopush/B27786-5.0-opt

This bug was intruduced by the fix for bug#17212 (in 4.1). It is not 
ok to call test_if_skip_sort_order since this function will 
alter the execution plan. By contract it is not ok to call 
test_if_skip_sort_order in this context.

This bug appears only in the case when the optimizer has chosen 
an index for accessing a particular table but finds a covering 
index that enables it to skip ORDER BY. This happens in 
test_if_skip_sort_order.

into  romeo.(none):/home/bk/merge-mysql-5.1

into  romeo.(none):/home/bk/merge-mysql-5.1

into  romeo.(none):/home/bk/merge-mysql-5.0

into  romeo.(none):/home/bkroot/mysql-5.0-rpl

into  romeo.(none):/home/bk/b27779-mysql-5.1-rpl

When merging views into the enclosing statement
the ORDER BY clause of the view is merged to the
parent's ORDER BY clause.
However when the VIEW is merged into an UNION
branch the ORDER BY should be ignored. 
Use of ORDER BY for individual SELECT statements
implies nothing about the order in which the rows
appear in the final result because UNION by default
produces unordered set of rows.
Fixed by ignoring the ORDER BY clause from the merge
view when expanded in an UNION branch.

into  magare.gmz:/home/kgeorge/mysql/autopush/B27530-5.0-opt