Addendum fixes after changing the condition variable
for the global read lock.
The stress test suite revealed some deadlocks. Some were
related to the new condition variable (COND_global_read_lock)
and some were general problems with the global read lock.
It is now necessary to signal COND_global_read_lock whenever
COND_refresh is signalled.
We need to wait for the release of a global read lock if one
is set before every operation that requires a write lock.
But we must not wait if we have locked tables by LOCK TABLES.
After setting a global read lock a thread waits until all
write locks are released.
Fixes bug#17264, for alter table on win32 for successfull operation completion
it is used TL_WRITE(=10) lock instead of TL_WRITE_ALLOW_READ(=6), however here
in innodb handler TL_WRTIE is lifted to TL_WRITE_ALLOW_WRITE, which causes
race condition when several clients do alter table simultaneously.
The order of acquiring LOCK_mysql_create_db
and wait_if_global_read_lock() was wrong. It could happen
that a thread held LOCK_mysql_create_db while waiting for
the global read lock to be released. The thread with the
global read lock could try to administrate a database too.
It would first try to lock LOCK_mysql_create_db and hang...
The check if the current thread has the global read lock
is done in wait_if_global_read_lock(), which could not be
reached because of the hang in LOCK_mysql_create_db.
Now I exchanged the order of acquiring LOCK_mysql_create_db
and wait_if_global_read_lock(). This makes
wait_if_global_read_lock() fail with an error message for
the thread with the global read lock. No deadlock happens.
Replaced COND_refresh with COND_global_read_lock becasue of a bug in NTPL threads when using different mutexes as arguments to pthread_cond_wait()
The original code caused a hang in FLUSH TABLES WITH READ LOCK in some circumstances because pthread_cond_broadcast() was not delivered to other threads.
This fixes:
Bug#16986: Deadlock condition with MyISAM tables
Bug#20048: FLUSH TABLES WITH READ LOCK causes a deadlock
Use open_normal_and_derived_tables instead of open_and_lock_tables when reading metadata for a table.
Add two test cases, one for "USE database" and one for "SHOW COLUMNS FROM table"
Speed up column-completion in 'mysql'
Don't use ISAM if HAVE_ISAM is not defined
A lot of fixes for the embedded version. All libraries are now included in libmysqld.a
Changed arguments to convert_dirname() to make it more general.
Renamed files in the 'merge' directory to all use a common prefix.
Don't compile both assembler and C functions on x86
