WL#5363: Thread Pool Service Interface

In order to allow thread schedulers to be dynamically loaded,
it is necessary to make the following changes to the server:

- Two new service interfaces

- Modifications to InnoDB to inform the thread scheduler of state changes.

- Changes to the VIO subsystem for checking if data is available on a socket.

- Elimination of remains of the old thread pool implementation.

The two new service interfaces introduces are:

my_thread_scheduler
  A service interface to register a thread
  scheduler.

thd_wait
  A service interface to inform thread scheduler
  that the thread is about to start waiting.

In addition, the patch adds code that:

- Add a call to thd_wait for table locks in mysys
  thd_lock.c by introducing a set function that
  can be used to set a callback to be used when
  waiting on a lock and resuming from waiting.

- Calling the mysys set function from the server
  to set the callbacks correctly.

1 files changed, 1 insertions, 2 deletions

diff --git a/sql/mysqld.h b/sql/mysqld.h
index 2547100d8ff..3ad43df3208 100644
--- a/sql/mysqld.h
+++ b/sql/mysqld.h
@@ -177,7 +177,7 @@ extern ulong binlog_cache_size, open_files_limit;
 extern ulonglong max_binlog_cache_size;
 extern ulong max_binlog_size, max_relay_log_size;
 extern ulong opt_binlog_rows_event_max_size;
-extern ulong rpl_recovery_rank, thread_cache_size, thread_pool_size;
+extern ulong rpl_recovery_rank, thread_cache_size;
 extern ulong back_log;
 extern char language[FN_REFLEN];
 extern ulong server_id, concurrency;
@@ -211,7 +211,6 @@ extern int bootstrap_error;
 extern FILE *stderror_file;
 extern I_List<THD> threads;
 extern char err_shared_dir[];
-extern scheduler_functions thread_scheduler;
 extern TYPELIB thread_handling_typelib;
 extern my_decimal decimal_zero;