Changes in an item tree done by optimizer weren't properly
registered and went unnoticed, which resulted in preliminary freeing
of used memory.

  
User name (host name) has limit on length. The server code relies on these
limits when storing the names. The problem was that sometimes these limits
were not checked properly, so that could lead to buffer overflow.

The fix is to check length of user/host name in parser and if string is too
long, throw an error.

Implemented code review comments
Test cleanup

into  weblab.(none):/home/marcsql/TREE/mysql-5.0-8153

into  moonlight.intranet:/home/tomash/src/mysql_ab/mysql-5.0-bug21051-2

There were two problems: RESET QUERY CACHE took a long time to complete
and other threads were blocked during this time.

The patch does three things:
  1 fixes a bug with improper use of test-lock-test_again technique.
      AKA Double-Checked Locking is applicable here only in few places.
  2 Somewhat improves performance of RESET QUERY CACHE.
      Do my_hash_reset() instead of deleting elements one by one.  Note
      however that the slowdown also happens when inserting into sorted
      list of free blocks, should be rewritten using balanced tree.
  3 Makes RESET QUERY CACHE non-blocking.
      The patch adjusts the locking protocol of the query cache in the
      following way: it introduces a flag flush_in_progress, which is
      set when Query_cache::flush_cache() is in progress.  This call
      sets the flag on enter, and then releases the lock.  Every other
      call is able to acquire the lock, but does nothing if
      flush_in_progress is set (as if the query cache is disabled).
      The only exception is the concurrent calls to
      Query_cache::flush_cache(), that are blocked until the flush is
      over.  When leaving Query_cache::flush_cache(), the lock is
      acquired and the flag is reset, and one thread waiting on
      Query_cache::flush_cache() (if any) is notified that it may
      proceed.

into  mockturtle.local:/home/dlenev/src/mysql-5.0-bg21216-2

server to crash".

Crash caused by assertion failure happened when one ran SHOW OPEN TABLES
while concurrently doing DROP TABLE (or RENAME TABLE, CREATE TABLE LIKE
or any other command that takes name-lock) in other connection.
For non-debug version of server problem exposed itself as wrong output
of SHOW OPEN TABLES statement (it was missing name-locked tables).
Finally in 5.1 both debug and non-debug versions simply crashed in
this situation due to NULL-pointer dereference.

This problem was caused by the fact that table placeholders which were
added to table cache in order to obtain name-lock had TABLE_SHARE::table_name
set to 0. Therefore they broke assumption that this member is non-0 for
all tables in table cache which was checked by assert in list_open_tables()
(in 5.1 this function simply relies on it).
The fix simply sets this member for such placeholders to appropriate value
making this assumption true again.

This patch also includes test for similar bug 12212 "Crash that happens
during removing of database name from cache" reappeared in 5.1 as bug 19403.

Corrected build issues : the build can not be conditional.
to keep a unique source .tar.gz distribution.

Changed the automake build process :
- ./configure.in
- ./sql/Makefile.am
to compile an instrumented parser for debug=yes or debug=full builds

Changed the (primary) runtime invocation of the parser :
- sql/sql_parse.cc
to generate bison traces in stderr when the DBUG "parser_debug" flag is set.

into  mysql.com:/home/cps/mysql/trees/mysql-5.0-virgin

Before this fix,
- a runtime error in a statement in a stored procedure with no error handlers
was properly detected (as expected)
- a runtime error in a statement with an error handler inherited from a non
local runtime context (i.e., proc a with a handler, calling proc b) was
properly detected (as expected)
- a runtime error in a statement with a *local* error handler was executed
as follows :
a) the statement would succeed, regardless of the error condition, (bug)
b) the error handler would be called (as expected).

The root cause is that functions like my_messqge_sql would "forget" to set
the thread flag thd->net.report_error to 1, because of the check involving
sp_rcontext::found_handler_here().
Failure to set this flag would cause, later in the call stack,
in Item_func::fix_fields() at line 190, the code to return FALSE and consider
that executing the statement was successful.

With this fix :
- error handling code, that was duplicated in different places in the code,
is now implemented in sp_rcontext::handle_error(),
- handle_error() correctly sets thd->net.report_error when a handler is
present, regardless of the handler location (local, or in the call stack).

A test case, bug8153_subselect, has been written to demonstrate the change
of behavior before and after the fix.

Another test case, bug8153_function_a, as also been writen.
This test has the same behavior before and after the fix.
This test has been written to demonstrate that the previous expected
result of procedure bug18787, was incorrect, since select no_such_function()
should fail and therefore not produce a result.

The incorrect result for bug18787 has the same root cause as Bug#8153,
and the expected result has been adjusted.

into  bodhi.local:/opt/local/work/mysql-5.0-runtime-merge

into  moonbone.local:/work/tmp_merge-5.0-opt-mysql

into  moonbone.local:/work/tmp_merge-5.0-opt-mysql

into  moonbone.local:/work/tmp_merge-5.0-opt-mysql

into  moonbone.local:/work/tmp_merge-5.0-opt-mysql

into  moonbone.local:/work/tmp_merge-4.1-opt-mysql

into  moonbone.local:/work/tmp_merge-4.1-opt-mysql

into  mysql.com:/home/hf/work/mysql-4.1.20317

into  bodhi.local:/opt/local/work/mysql-5.0-runtime-merge

into  lmy002.wdf.sap.corp:/home/georg/work/mysql/prod/mysql-5.0

  Delete: mysql-test/t/sp.test.orig

Fixes:
- bug #19834: Using cursors when running in READ-COMMITTED can cause InnoDB to crash
- bug #21112: InnoDB slow with > 100,000 .ibd files
- bug #21113: Duplicate printout in SHOW INNODB STATUS

into  neptunus.(none):/home/msvensson/mysql/mysql-4.1

into  rakia.(none):/home/kgeorge/mysql/autopush/B20103-5.0-opt

 - make the client to respect the server-side 
   no_backslash_escapes option and disable the 
   special meaning of backslash also at client side.

into  mysql.com:/users/lthalmann/bk/MERGE/mysql-5.0-merge

into  mysql.com:/users/lthalmann/bk/MERGE/mysql-4.1-merge

into  rakia.(none):/home/kgeorge/mysql/autopush/B11551-5.0-opt

into  sunlight.local:/local_work/tmp_merge-5.0-opt-mysql

into  mysql.com:/users/lthalmann/bk/MERGE/mysql-5.0-merge

into  mysql.com:/users/lthalmann/bk/MERGE/mysql-5.0-merge

into  mysql.com:/users/lthalmann/bk/MERGE/mysql-4.1-merge

into  weblab.(none):/home/marcsql/TREE/mysql-5.0-21269

  After merge fix