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.


include/mysql_com.h:
  Add comment for NET::query_cache_query.
sql/net_serv.cc:
  Use query_cache_init_query() for initialization of
  NET::query_cache_query if query cache is used.
  Do not access net->query_cache_query without a lock.
sql/sql_cache.cc:
  Fix bug with accessing query_cache_size, Query_cache_query::wri and
  thd->net.query_cache_query before acquiring the lock---leave
  double-check locking only in safe places.
  Wherever we check that cache is usable (query_cache_size > 0) we now
  also check that flush_in_progress is false, i.e. we are not in the
  middle of cache flush.
  Add Query_cache::not_in_flush_or_wait() method and use it in
  Query_cache::flush_cache(), so that threads doing cache flush will
  wait it to finish, while other threads will bypass the cache as if
  it is disabled.
  Extract Query_cache::free_query_internal() from Query_cache::free_query(),
  which does not removes elements from the hash, and use it together with
  my_hash_reset() in Query_cache::flush_cache().
sql/sql_cache.h:
  Add declarations for new members and methods.
  Make is_cacheable() a static method.
  Add query_cache_init_query() function.
sql/sql_class.cc:
  Use query_cache_init_query() for initialization of
  NET::query_cache_query.

  
Fix for the bug in mysql-test-run.pl which prevents other tests succeed
after IM-test failure.
  
The idea of the fix of BUG#20716 is to:
  1. Check each SHOW INSTANCES statement, add necessary "sleep" instruction before;
  2. Move all environment checkings into the one file and include it everywhere.


mysql-test/mysql-test-run.pl:
  Fix bug in mysql-test-run.pl -- kill leftovers if some
  guarded mysqld-instance is still alive after IM shutdown.
mysql-test/r/im_daemon_life_cycle.result:
  Updated result file.
mysql-test/r/im_life_cycle.result:
  Updated result file.
mysql-test/r/im_options_set.result:
  Updated result file.
mysql-test/r/im_options_unset.result:
  Updated result file.
mysql-test/r/im_utils.result:
  Updated result file.
mysql-test/t/im_daemon_life_cycle.imtest:
  Include im_check_env.inc for the checking of environment.
mysql-test/t/im_life_cycle.imtest:
  Include im_check_env.inc for the checking of environment.
mysql-test/t/im_options_set.imtest:
  Include im_check_env.inc for the checking of environment.
mysql-test/t/im_options_unset.imtest:
  Include im_check_env.inc for the checking of environment.
mysql-test/t/im_utils.imtest:
  Include im_check_env.inc for the checking of environment.
mysql-test/include/im_check_env.inc:
  A new file to be included in each IM-test.
  The statements in the file ensure that starting
  conditions (environment) are as expected.

into  moonlight.intranet:/home/tomash/src/mysql_ab/mysql-5.0-bug21013

           and Stored Procedure

The essence of the bug was that for every re-execution of stored
routine or prepared statement new items for character set conversions
were created, thus increasing the number of items and the time of their
processing, and creating memory leak.

No test case is provided since current test suite can't cover such type
of bugs.


mysql-test/r/sp.result:
  Add result for bug#21013: Performance Degrades when importing data
  that uses Trigger and Stored Procedure.
mysql-test/t/sp.test:
  Add test case for bug#21013: Performance Degrades when importing data
  that uses Trigger and Stored Procedure.
sql/item.cc:
  Switch arena only when in statement prepare mode.  Subsequent executions
  will use cached item tree.

into  moonlight.intranet:/home/tomash/src/mysql_ab/mysql-5.0-bug18630


sql/item_func.cc:
  Auto merged
sql/item_func.h:
  Auto merged
sql/sql_parse.cc:
  Auto merged
sql/sql_trigger.cc:
  Auto merged

           context.

Routine arguments were evaluated in the security context of the routine
itself, not in the caller's context.

The bug is fixed the following way:

  - Item_func_sp::find_and_check_access() has been split into two
    functions: Item_func_sp::find_and_check_access() itself only
    finds the function and check that the caller have EXECUTE privilege
    on it.  New function set_routine_security_ctx() changes security
    context for SUID routines and checks that definer have EXECUTE
    privilege too.

  - new function sp_head::execute_trigger() is called from
    Table_triggers_list::process_triggers() instead of
    sp_head::execute_function(), and is effectively just as the
    sp_head::execute_function() is, with all non-trigger related code
    removed, and added trigger-specific security context switch.

  - call to Item_func_sp::find_and_check_access() stays outside
    of sp_head::execute_function(), and there is a code in
    sql_parse.cc before the call to sp_head::execute_procedure() that
    checks that the caller have EXECUTE privilege, but both
    sp_head::execute_function() and sp_head::execute_procedure() call
    set_routine_security_ctx() after evaluating their parameters,
    and restore the context after the body is executed.


mysql-test/r/sp-security.result:
  Add test case for bug#18630: Arguments of suid routine calculated
  in wrong security context.
mysql-test/t/sp-security.test:
  Add result for bug#18630: Arguments of suid routine calculated
  in wrong security context.
sql/item_func.cc:
  Do not change security context before executing the function, as it
  will be changed after argument evaluation.
  Do not change security context in Item_func_sp::find_and_check_access().
sql/item_func.h:
  Change prototype for Item_func_sp::find_and_check_access().
sql/sp_head.cc:
  Add set_routine_security_ctx() function.
  Add sp_head::execute_trigger() method.
  Change security context in sp_head::execute_trigger(), and in
  sp_head::execute_function() and sp_head::execute_procedure()
  after argument evaluation.
  Move pop_all_cursors() call to sp_head::execute().
sql/sp_head.h:
  Add declaration for sp_head::execute_trigger() and
  set_routine_security_ctx().
sql/sql_parse.cc:
  Do not change security context before executing the procedure, as it
  will be changed after argument evaluation.
sql/sql_trigger.cc:
  Call new sp_head::execute_trigger() instead of
  sp_head::execute_function(), which is responsible to switch
  security context.

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

sql/item_timefunc.cc:
  Fix a valgrind warning in type_date test.	

into  dl145k.mysql.com:/data0/mkindahl/bk/mysql-5.0-rpl


ndb/include/kernel/GlobalSignalNumbers.h:
  Auto merged
ndb/src/kernel/blocks/dbdict/Dbdict.cpp:
  Auto merged
ndb/src/kernel/blocks/dbdict/Dbdict.hpp:
  Auto merged
ndb/src/kernel/blocks/dbdih/DbdihMain.cpp:
  Auto merged
ndb/src/ndbapi/ndberror.c:
  Auto merged
sql/ha_ndbcluster.cc:
  Auto merged
sql/handler.h:
  Auto merged
sql/sql_base.cc:
  Auto merged
sql/sql_insert.cc:
  Auto merged

when dropping/creating tables"


mysql-test/r/ps.result:
  A post-merge fix.
mysql-test/t/ps.test:
  A post-merge fix: all 5.0 tests should go after 4.1 tests.
sql/sql_lex.cc:
  auxilliary -> auxiliary
sql/sql_prepare.cc:
  auxilliary -> auxiliary
sql/table.cc:
  Update st_table_list::reinit_before_use in 5.0 to include 5.0-specific
  cleanups.
sql/table.h:
  st_table_list::reinit_before_use is public.

into  bodhi.local:/opt/local/work/mysql-5.0-runtime-merge-41


ndb/src/mgmsrv/ConfigInfo.cpp:
  Auto merged
sql/table.cc:
  Auto merged
mysql-test/r/ps.result:
  Manual merge: use local.
mysql-test/t/ps.test:
  Manual merge: remove duplicate test cases from ps.test.
sql/sql_lex.cc:
  Manual merge.
sql/sql_prepare.cc:
  Manual merge.
sql/table.h:
  Manual merge.

into  bodhi.local:/opt/local/work/mysql-5.0-runtime-merge-41


sql/sql_table.cc:
  Auto merged

into  chilla.local:/home/mydev/mysql-5.0-amerge


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

into  trift2.:/M50/mysql-5.0

into  dl145k.mysql.com:/data0/mkindahl/bk/MERGE/mysql-5.0-merge


ndb/include/kernel/GlobalSignalNumbers.h:
  Auto merged
ndb/src/kernel/blocks/dbdict/Dbdict.cpp:
  Auto merged
ndb/src/kernel/blocks/dbdict/Dbdict.hpp:
  Auto merged
ndb/src/kernel/blocks/dbdih/DbdihMain.cpp:
  Auto merged
ndb/src/ndbapi/ndberror.c:
  Auto merged

into  bodhi.local:/opt/local/work/mysql-5.0-runtime-merge-41


sql/opt_range.cc:
  Auto merged
support-files/mysql.spec.sh:
  Auto merged
mysql-test/Makefile.am:
  Manual merge.

sql/sql_locale.cc:
  "true" -> TRUE

into  trift2.:/M50/mysql-5.0


configure.in:
  Auto merged

sql/sql_locale.cc:
  Fix Windows compilation failure "cannot convert from 'const char [6]' 
  to 'const BOOL'" and an apparent bug (use of "FALSE" instead of FALSE
  for initialization of is_ascii member of MY_LOCALE)

into  gbichot3.local:/home/mysql_src/mysql-5.0

mysql-test/r/myisam.result:
  Fix test results.
mysql-test/t/myisam.test:
  In 5.0 show create table also outputs data directory.
  For the test for Bug#8706 it's MYSQLTEST_VARDIR, and there is no way
  to replace it with anything else in test output.

into  orca.ndb.mysql.com:/space_old/pekka/ndb/version/my50-1.2167.1.2


ndb/include/kernel/GlobalSignalNumbers.h:
  Auto merged
ndb/src/common/debugger/signaldata/SignalNames.cpp:
  Auto merged
ndb/src/kernel/blocks/dbdih/DbdihMain.cpp:
  Auto merged
ndb/src/kernel/blocks/ndbcntr/NdbcntrMain.cpp:
  Auto merged
ndb/test/run-test/daily-basic-tests.txt:
  Auto merged

ndb/src/kernel/blocks/dbdict/DictLock.txt:
  wait until SL_STARTED before sending DICT_UNLOCK_ORD
ndb/src/kernel/blocks/dbdih/Dbdih.hpp:
  wait until SL_STARTED before sending DICT_UNLOCK_ORD
ndb/src/kernel/blocks/dbdih/DbdihMain.cpp:
  wait until SL_STARTED before sending DICT_UNLOCK_ORD
ndb/src/kernel/vm/SimulatedBlock.cpp:
  wait until SL_STARTED before sending DICT_UNLOCK_ORD
ndb/src/kernel/vm/SimulatedBlock.hpp:
  wait until SL_STARTED before sending DICT_UNLOCK_ORD
ndb/test/run-test/daily-basic-tests.txt:
  wait until SL_STARTED before sending DICT_UNLOCK_ORD

ndb/include/kernel/GlobalSignalNumbers.h:
  5.0 : add NODE_START_REP from 5.1
ndb/src/common/debugger/signaldata/SignalNames.cpp:
  5.0 : add NODE_START_REP from 5.1
ndb/src/kernel/blocks/ndbcntr/NdbcntrMain.cpp:
  5.0 : add NODE_START_REP from 5.1
ndb/src/kernel/vm/SimulatedBlock.cpp:
  5.0 : add NODE_START_REP from 5.1
ndb/src/kernel/vm/SimulatedBlock.hpp:
  5.0 : add NODE_START_REP from 5.1

fails"


mysql-test/t/myisam.test:
  Fix myisam.test to work with non-default mysqltest var directory.

VC++Files/libmysqld/libmysqld.dsp:
  Add sql_locale.cpp
VC++Files/libmysqld/libmysqld.vcproj:
  Add sql_locale.cpp
VC++Files/sql/mysqld.dsp:
  Add sql_locale.cpp
VC++Files/sql/mysqld.vcproj:
  Add sql_locale.cpp

into  orca.ndb.mysql.com:/space_old/pekka/ndb/version/my50

ndb/src/kernel/blocks/dbtup/DbtupMeta.cpp:
  non-debug compile fix

into  dsl-hkigw8-feb1fb00-100.dhcp.inet.fi:/usr_rh9/home/elkin.rh9/MySQL/TEAM/FIXES/5.0/20919_temp_nlog


sql/sql_base.cc:
  Manual merge

into  trift2.:/M50/mysql-5.0

support-files/mysql.spec.sh:
  Fix a typing error in the "make" target for the Perl script to run the tests.

into  trift2.:/M50/back23-5.0


support-files/mysql.spec.sh:
  Auto merged

into  orca.ndb.mysql.com:/space_old/pekka/ndb/version/my50-bug20847

mysql-test/Makefile.am:
  fix cp of mode 444 files

into  orca.ndb.mysql.com:/space_old/pekka/ndb/version/my50-bug20847

closing temp tables through end_thread
had a flaw in binlog-off branch of close_temporary_tables where
next table to close was reset via table->next
 for (table= thd->temporary_tables; table; table= table->next)
which was wrong since the current table instance got destoyed at
	close_temporary(table, 1);

The fix adapts binlog-on branch method to engage the loop's internal 'next' variable which holds table->next prior table's destoying.



sql/sql_base.cc:
  no-binlog branch is fixed: scanning across temporary_tables must be careful to save next table since the current is being destroyed inside of close_temporary. 
  binlog-is-open case is ok.

between pointer to function and pointer to object.


sql/item_func.cc:
  Use typedef names instead of hard-coded types for udf init/deinit
  functions.
sql/sql_udf.cc:
  Use typedef names for udf function types.