branches/zip: Enclose the definition of dict_index_t::trx_id in

#ifdef ROW_MERGE_IS_INDEX_USABLE, to avoid growing the memory
footprint until MySQL implements and calls the virtual method
handler::is_index_available() or something equivalent.

dict/dict0crea.c

@@ -554,8 +554,10 @@ dict_build_index_def_step(
 
 	ins_node_set_new_row(node->ind_def, row);
 
+#ifdef ROW_MERGE_IS_INDEX_USABLE
 	/* Note that the index was created by this transaction. */
 	index->trx_id = trx->id;
+#endif /* ROW_MERGE_IS_INDEX_USABLE */
 
 	return(DB_SUCCESS);
 }

handler/ha_innodb.cc

@@ -3906,6 +3906,7 @@ ha_innobase::try_semi_consistent_read(bool yes)
 	}
 }
 
+#ifdef ROW_MERGE_IS_INDEX_USABLE
 /**********************************************************************
 Check if an index can be used by the optimizer. */
 
@@ -3915,11 +3916,11 @@ ha_innobase::is_index_available(
 					/* out: true if available else false*/
 	uint		keynr)		/* in: index number to check */
 {
-	DBUG_ENTER("is_index_available");
+	DBUG_ENTER("ha_innobase::is_index_available");
 
 	if (table && keynr != MAX_KEY && table->s->keys > 0) {
-		dict_index_t*	index;
-		KEY*		key = table->key_info + keynr;
+		const dict_index_t*	index;
+		const KEY*		key = table->key_info + keynr;
 
 		ut_ad(user_thd == ha_thd());
 		ut_a(prebuilt->trx == thd_to_trx(user_thd));
@@ -3935,6 +3936,7 @@ ha_innobase::is_index_available(
 
 	DBUG_RETURN(true);
 }
+#endif /* ROW_MERGE_IS_INDEX_USABLE */
 
 /**********************************************************************
 Initializes a handle to use an index. */

handler/ha_innodb.h

@@ -121,7 +121,14 @@ class ha_innobase: public handler
 	void try_semi_consistent_read(bool yes);
 	void unlock_row();
 
-	bool is_index_available(uint index);
+#ifdef ROW_MERGE_IS_INDEX_USABLE
+	/** Check if an index can be used by this transaction.
+	* @param keynr	key number to check
+	* @return	true if available, false if the index
+	*		does not contain old records that exist
+	*		in the read view of this transaction */
+	bool is_index_available(uint keynr);
+#endif /* ROW_MERGE_IS_INDEX_USABLE */
 	int index_init(uint index, bool sorted);
 	int index_end();
 	int index_read(uchar * buf, const uchar * key,

include/dict0mem.h

@@ -239,9 +239,11 @@ struct dict_index_struct{
 				index tree */
 	rw_lock_t	lock;	/* read-write lock protecting the upper levels
 				of the index tree */
+#ifdef ROW_MERGE_IS_INDEX_USABLE
 	dulint		trx_id; /* id of the transaction that created this
-				index. It can be zero which implies that
-				it was created on database startup.*/
+				index, or ut_dulint_zero if the index existed
+				when InnoDB was started up */
+#endif /* ROW_MERGE_IS_INDEX_USABLE */
 #ifdef UNIV_DEBUG
 	ulint		magic_n;/* magic number */
 # define DICT_INDEX_MAGIC_N	76789786

include/row0merge.h

@@ -122,6 +122,7 @@ row_merge_create_index(
 	dict_table_t*	table,		/* in: the index is on this table */
 	const merge_index_def_t*	/* in: the index definition */
 			index_def);
+#ifdef ROW_MERGE_IS_INDEX_USABLE
 /*************************************************************************
 Check if a transaction can use an index. */
 
@@ -132,6 +133,7 @@ row_merge_is_index_usable(
 					the transaction else FALSE*/
 	const trx_t*		trx,	/* in: transaction */
 	const dict_index_t*	index);	/* in: index to check */
+#endif /* ROW_MERGE_IS_INDEX_USABLE */
 /*************************************************************************
 If there are views that refer to the old table name then we "attach" to
 the new instance of the table else we drop it immediately. */

row/row0merge.c

@@ -1876,10 +1876,12 @@ row_merge_create_index(
 
 			ut_a(index);
 
+#ifdef ROW_MERGE_IS_INDEX_USABLE
 			/* Note the id of the transaction that created this
 			index, we use it to restrict readers from accessing
 			this index, to ensure read consistency. */
 			index->trx_id = trx->id;
+#endif /* ROW_MERGE_IS_INDEX_USABLE */
 
 			/* Create element and append to list in trx. So that
 			we can rename from temp name to real name. */
@@ -1899,6 +1901,7 @@ row_merge_create_index(
 	return(index);
 }
 
+#ifdef ROW_MERGE_IS_INDEX_USABLE
 /*************************************************************************
 Check if a transaction can use an index. */
 
@@ -1914,6 +1917,7 @@ row_merge_is_index_usable(
 
 	return(ut_dulint_cmp(index->trx_id, trx->read_view->low_limit_id) < 0);
 }
+#endif /* ROW_MERGE_IS_INDEX_USABLE */
 
 /*************************************************************************
 Drop the old table. */