Implement INFORMATION_SCHEMA tables innodb_trx, innodb_locks,

innodb_lock_waits. See
https://svn.innodb.com/innobase/InformationSchema/TransactionsAndLocks
for design notes.

Things that need to be resolved before this goes live:
* MySQL must add thd_get_thread_id() function to their code
  http://bugs.mysql.com/30930
* Allocate memory from mem_heap instead of using mem_alloc()
* Copy table name and index name into the cache because they may be
  freed later which will result in referencing freed memory

Approved by:	Marko

Makefile.am

@@ -104,6 +104,7 @@ noinst_HEADERS = include/btr0btr.h include/btr0btr.ic			\
 			include/sync0rw.ic include/sync0sync.h		\
 			include/sync0sync.ic include/sync0types.h	\
 			include/thr0loc.h include/thr0loc.ic		\
+			include/trx0i_s.h				\
 			include/trx0purge.h include/trx0purge.ic	\
 			include/trx0rec.h include/trx0rec.ic		\
 			include/trx0roll.h include/trx0roll.ic		\
@@ -123,7 +124,8 @@ noinst_HEADERS = include/btr0btr.h include/btr0btr.ic			\
 			include/ut0vec.ic include/ut0list.h		\
 			include/ut0list.ic include/ut0wqueue.h		\
 			include/ha_prototypes.h handler/ha_innodb.h	\
-			include/handler0alter.h
+			include/handler0alter.h				\
+			handler/i_s.h
 
 EXTRA_LIBRARIES =	libinnobase.a
 noinst_LIBRARIES =	@plugin_innobase_static_target@
@@ -154,13 +156,16 @@ libinnobase_a_SOURCES =	btr/btr0btr.c btr/btr0cur.c btr/btr0pcur.c	\
 			row/row0undo.c row/row0upd.c row/row0vers.c	\
 			srv/srv0que.c srv/srv0srv.c srv/srv0start.c	\
 			sync/sync0arr.c sync/sync0rw.c			\
-			sync/sync0sync.c thr/thr0loc.c trx/trx0purge.c	\
+			sync/sync0sync.c thr/thr0loc.c			\
+			trx/trx0i_s.c					\
+			trx/trx0purge.c					\
 			trx/trx0rec.c trx/trx0roll.c trx/trx0rseg.c	\
 			trx/trx0sys.c trx/trx0trx.c trx/trx0undo.c	\
 			usr/usr0sess.c ut/ut0byte.c ut/ut0dbg.c		\
 			ut/ut0list.c ut/ut0mem.c ut/ut0rnd.c		\
 			ut/ut0ut.c ut/ut0vec.c ut/ut0wqueue.c		\
-			handler/ha_innodb.cc handler/handler0alter.cc
+			handler/ha_innodb.cc handler/handler0alter.cc	\
+			handler/i_s.cc
 
 libinnobase_a_CXXFLAGS=	$(AM_CFLAGS)
 libinnobase_a_CFLAGS  =	$(AM_CFLAGS)

handler/ha_innodb.cc

@@ -34,6 +34,7 @@
 #include <mysys_err.h>
 #include <my_sys.h>
 #include "ha_innodb.h"
+#include "i_s.h"
 #include <mysql/plugin.h>
 
 #ifndef MYSQL_SERVER
@@ -8388,5 +8389,8 @@ mysql_declare_plugin(innobase)
   innobase_stat_zip_deinit,
   0x0100 /* 1.0 */,
   NULL, NULL, NULL
-}
+},
+i_s_innodb_trx,
+i_s_innodb_locks,
+i_s_innodb_lock_waits
 mysql_declare_plugin_end;

handler/i_s.h

+/******************************************************
+InnoDB INFORMATION SCHEMA tables interface to MySQL.
+
+(c) 2007 Innobase Oy
+
+Created July 18, 2007 Vasil Dimov
+*******************************************************/
+
+#ifndef i_s_h
+#define i_s_h
+
+extern struct st_mysql_plugin	i_s_innodb_trx;
+extern struct st_mysql_plugin	i_s_innodb_locks;
+extern struct st_mysql_plugin	i_s_innodb_lock_waits;
+
+#endif /* i_s_h */

include/sync0sync.h

@@ -383,6 +383,9 @@ or row lock! */
 					their level set after the page is
 					locked; see e.g.
 					ibuf_bitmap_get_map_page(). */
+#define SYNC_INFORMATION_SCHEMA	1900	/* Used when latching
+					INFORMATION SCHEMA internal
+					structures. */
 #define	SYNC_DICT_OPERATION	1001	/* table create, drop, etc. reserve
 					this in X-mode, implicit or backround
 					operations purge, rollback, foreign

include/trx0i_s.h

+/******************************************************
+INFORMATION SCHEMA innodb_trx, innodb_locks and
+innodb_lock_waits tables cache structures and public
+functions.
+
+(c) 2007 Innobase Oy
+
+Created July 17, 2007 Vasil Dimov
+*******************************************************/
+
+#ifndef trx0i_s_h
+#define trx0i_s_h
+
+#include "univ.i"
+#include "ut0ut.h"
+
+typedef struct i_s_locks_row_struct	i_s_locks_row_t;
+typedef struct i_s_hash_chain_struct	i_s_hash_chain_t;
+
+/* Objects of this type are added to the hash table
+trx_i_s_cache_t::locks_hash */
+struct i_s_hash_chain_struct {
+	i_s_locks_row_t*	value;
+	i_s_hash_chain_t*	next;
+};
+
+/* This structure represents INFORMATION_SCHEMA.innodb_locks row */
+struct i_s_locks_row_struct {
+	ullint		lock_trx_id;
+	const char*	lock_mode;
+	const char*	lock_type;
+	const char*	lock_table;
+	const char*	lock_index;
+	ulint		lock_space;
+	ulint		lock_page;
+	ulint		lock_rec;
+	/* The following are auxiliary and not included in the table */
+	ullint		lock_table_id;
+	i_s_hash_chain_t hash_chain; /* this object is added to the hash
+				    table
+				    trx_i_s_cache_t::locks_hash */
+};
+
+/* This structure represents INFORMATION_SCHEMA.innodb_trx row */
+typedef struct i_s_trx_row_struct {
+	ullint			trx_id;
+	const char*		trx_state;
+	ib_time_t		trx_started;
+	const i_s_locks_row_t*	wait_lock_row;
+	ib_time_t		trx_wait_started;
+	ulint			trx_mysql_thread_id;
+} i_s_trx_row_t;
+
+/* This structure represents INFORMATION_SCHEMA.innodb_lock_waits row */
+typedef struct i_s_lock_waits_row_struct {
+	const i_s_locks_row_t*	wait_lock_row;
+	const i_s_locks_row_t*	waited_lock_row;
+} i_s_lock_waits_row_t;
+
+/* This type is opaque and is defined in trx/trx0i_s.c */
+typedef struct trx_i_s_cache_struct	trx_i_s_cache_t;
+
+/* Auxiliary enum used by functions that need to select one of the
+INFORMATION_SCHEMA tables */
+enum i_s_table {
+	I_S_INNODB_TRX,
+	I_S_INNODB_LOCKS,
+	I_S_INNODB_LOCK_WAITS
+};
+
+/* This is the intermediate buffer where data needed to fill the
+INFORMATION SCHEMA tables is fetched and later retrieved by the C++
+code in handler/i_s.cc. */
+extern trx_i_s_cache_t*	trx_i_s_cache;
+
+/***********************************************************************
+Initialize INFORMATION SCHEMA trx related cache. */
+
+void
+trx_i_s_cache_init(
+/*===============*/
+	trx_i_s_cache_t*	cache);	/* out: cache to init */
+
+/***********************************************************************
+Issue a shared/read lock on the tables cache. */
+
+void
+trx_i_s_cache_start_read(
+/*=====================*/
+	trx_i_s_cache_t*	cache);	/* in: cache */
+
+/***********************************************************************
+Release a shared/read lock on the tables cache. */
+
+void
+trx_i_s_cache_end_read(
+/*===================*/
+	trx_i_s_cache_t*	cache);	/* in: cache */
+
+/***********************************************************************
+Issue an exclusive/write lock on the tables cache. */
+
+void
+trx_i_s_cache_start_write(
+/*======================*/
+	trx_i_s_cache_t*	cache);	/* in: cache */
+
+/***********************************************************************
+Release an exclusive/write lock on the tables cache. */
+
+void
+trx_i_s_cache_end_write(
+/*====================*/
+	trx_i_s_cache_t*	cache);	/* in: cache */
+
+
+/***********************************************************************
+Retrieves the number of used rows in the cache for a given
+INFORMATION SCHEMA table. */
+
+ullint
+trx_i_s_cache_get_rows_used(
+/*========================*/
+					/* out: number of rows */
+	trx_i_s_cache_t*	cache,	/* in: cache */
+	enum i_s_table		table);	/* in: which table */
+
+/***********************************************************************
+Retrieves the nth row in the cache for a given INFORMATION SCHEMA
+table. */
+
+void*
+trx_i_s_cache_get_nth_row(
+/*======================*/
+					/* out: row */
+	trx_i_s_cache_t*	cache,	/* in: cache */
+	enum i_s_table		table,	/* in: which table */
+	ulint			n);	/* in: row number */
+
+/***********************************************************************
+Update the transactions cache if it has not been read for some time. */
+
+int
+trx_i_s_possibly_fetch_data_into_cache(
+/*===================================*/
+					/* out: 0 - fetched, 1 - not */
+	trx_i_s_cache_t*	cache);	/* in/out: cache */
+
+/* The maximum length that may be required by lock_id_sz in
+trx_i_s_create_lock_id(). "%llu:%lu:%lu:%lu" -> 84 chars */
+
+#define TRX_I_S_LOCK_ID_MAX_LEN	84
+
+/***********************************************************************
+Crafts a lock id string from a i_s_locks_row_t object. Returns its
+second argument. This function aborts if there is not enough space in
+lock_id. Be sure to provide at least TRX_I_S_LOCK_ID_MAX_LEN if you want
+to be 100% sure that it will not abort. */
+
+char*
+trx_i_s_create_lock_id(
+/*===================*/
+					/* out: resulting lock id */
+	const i_s_locks_row_t*	row,	/* in: innodb_locks row */
+	char*			lock_id,/* out: resulting lock_id */
+	ulint			lock_id_size);/* in: size of the lock id
+					buffer */
+
+#endif /* trx0i_s_h */

srv/srv0srv.c

@@ -49,6 +49,7 @@ Created 10/8/1995 Heikki Tuuri
 #include "srv0start.h"
 #include "row0mysql.h"
 #include "ha_prototypes.h"
+#include "trx0i_s.h"
 
 /* This is set to TRUE if the MySQL user has set it in MySQL; currently
 affects only FOREIGN KEY definition parsing */
@@ -938,6 +939,9 @@ srv_init(void)
 		conc_slot->event = os_event_create(NULL);
 		ut_a(conc_slot->event);
 	}
+
+	/* Initialize some INFORMATION SCHEMA internal structures */
+	trx_i_s_cache_init(trx_i_s_cache);
 }
 
 /*************************************************************************