branches/zip:

Copy any data (currently table name and table index) that may be
destroyed after releasing the kernel mutex into internal cache's
storage.

This is done in efficient manner using ha_storage type and a given
string is copied only once into the cache's storage. Later additions of
the same string use the already stored string, thus allocating memory
only once per unique string.

Approved by:	Marko

trx/trx0i_s.c

@@ -14,6 +14,7 @@ Created July 17, 2007 Vasil Dimov
 #include <mysql/plugin.h>
 
 #include "univ.i"
+#include "ha0storage.h"
 #include "hash0hash.h"
 #include "lock0iter.h"
 #include "lock0lock.h"
@@ -118,10 +119,16 @@ struct trx_i_s_cache_struct {
 	i_s_table_cache_t innodb_locks;	/* innodb_locks table */
 	i_s_table_cache_t innodb_lock_waits;/* innodb_lock_waits table */
 /* the hash table size is LOCKS_HASH_CELLS_NUM * sizeof(void*) bytes */
-#define LOCKS_HASH_CELLS_NUM	10000
+#define LOCKS_HASH_CELLS_NUM		10000
 	hash_table_t*	locks_hash;	/* hash table used to eliminate
 					duplicate entries in the
 					innodb_locks table */
+#define CACHE_STORAGE_INITIAL_SIZE	1024
+#define CACHE_STORAGE_HASH_CELLS	2048
+	ha_storage_t*	storage;	/* storage for external volatile
+					data that can possibly not be
+					available later, when we release
+					the kernel mutex */
 };
 
 /* This is the intermediate buffer where data needed to fill the
@@ -362,21 +369,23 @@ fill_locks_row(
 				/* out: result object that's filled */
 	i_s_locks_row_t* row,	/* out: result object that's filled */
 	const lock_t*	lock,	/* in: lock to get data from */
-	ulint		heap_no)/* in: lock's record number
+	ulint		heap_no,/* in: lock's record number
 				or ULINT_UNDEFINED if the lock
 				is a table lock */
+	trx_i_s_cache_t* cache)	/* in/out: cache into which to copy
+				volatile strings */
 {
 	row->lock_trx_id = lock_get_trx_id(lock);
 	row->lock_mode = lock_get_mode_str(lock);
 	row->lock_type = lock_get_type_str(lock);
 
-	/* XXX this may be freed later */
-	row->lock_table = lock_get_table_name(lock);
+	row->lock_table = ha_storage_put_str(
+		cache->storage, lock_get_table_name(lock));
 
 	switch (lock_get_type(lock)) {
 	case LOCK_REC:
-		/* XXX this may be freed later */
-		row->lock_index = lock_rec_get_index_name(lock);
+		row->lock_index = ha_storage_put_str(
+			cache->storage, lock_rec_get_index_name(lock));
 
 		row->lock_space = lock_rec_get_space_id(lock);
 		row->lock_page = lock_rec_get_page_no(lock);
@@ -590,7 +599,7 @@ add_lock_to_cache(
 	dst_row = (i_s_locks_row_t*)
 		table_cache_create_empty_row(&cache->innodb_locks);
 
-	fill_locks_row(dst_row, lock, heap_no);
+	fill_locks_row(dst_row, lock, heap_no, cache);
 
 #ifndef TEST_DO_NOT_INSERT_INTO_THE_HASH_TABLE
 	HASH_INSERT(
@@ -753,7 +762,10 @@ trx_i_s_cache_clear(
 	cache->innodb_trx.rows_used = 0;
 	cache->innodb_locks.rows_used = 0;
 	cache->innodb_lock_waits.rows_used = 0;
+
 	hash_table_clear(cache->locks_hash);
+
+	ha_storage_empty(&cache->storage);
 }
 
 /***********************************************************************
@@ -835,6 +847,9 @@ trx_i_s_cache_init(
 			 sizeof(i_s_lock_waits_row_t));
 
 	cache->locks_hash = hash_create(LOCKS_HASH_CELLS_NUM);
+
+	cache->storage = ha_storage_create(CACHE_STORAGE_INITIAL_SIZE,
+					   CACHE_STORAGE_HASH_CELLS);
 }
 
 /***********************************************************************