Partial fix for Bug#11764622 57480: MEMORY LEAK WHEN HAVING 256+ TABLES

Port vasil.dimov@oracle.com-20111205082831-7v1qu50hvd9hjr3g from mysql-trunk

storage/innobase/btr/btr0pcur.c

@@ -52,12 +52,13 @@ btr_pcur_create_for_mysql(void)
 }
 
 /**************************************************************//**
-Frees the memory for a persistent cursor object. */
+Resets a persistent cursor object, freeing ::old_rec_buf if it is
+allocated and resetting the other members to their initial values. */
 UNIV_INTERN
 void
-btr_pcur_free_for_mysql(
-/*====================*/
-	btr_pcur_t*	cursor)	/*!< in, own: persistent cursor */
+btr_pcur_reset(
+/*===========*/
+	btr_pcur_t*	cursor)	/*!< in, out: persistent cursor */
 {
 	if (cursor->old_rec_buf != NULL) {
 
@@ -66,6 +67,7 @@ btr_pcur_free_for_mysql(
 		cursor->old_rec_buf = NULL;
 	}
 
+	cursor->btr_cur.index = NULL;
 	cursor->btr_cur.page_cur.rec = NULL;
 	cursor->old_rec = NULL;
 	cursor->old_n_fields = 0;
@@ -73,7 +75,17 @@ btr_pcur_free_for_mysql(
 
 	cursor->latch_mode = BTR_NO_LATCHES;
 	cursor->pos_state = BTR_PCUR_NOT_POSITIONED;
+}
 
+/**************************************************************//**
+Frees the memory for a persistent cursor object. */
+UNIV_INTERN
+void
+btr_pcur_free_for_mysql(
+/*====================*/
+	btr_pcur_t*	cursor)	/*!< in, own: persistent cursor */
+{
+	btr_pcur_reset(cursor);
 	mem_free(cursor);
 }
 

storage/innobase/include/btr0pcur.h

@@ -53,6 +53,16 @@ UNIV_INTERN
 btr_pcur_t*
 btr_pcur_create_for_mysql(void);
 /*============================*/
+
+/**************************************************************//**
+Resets a persistent cursor object, freeing ::old_rec_buf if it is
+allocated and resetting the other members to their initial values. */
+UNIV_INTERN
+void
+btr_pcur_reset(
+/*===========*/
+	btr_pcur_t*	cursor);/*!< in, out: persistent cursor */
+
 /**************************************************************//**
 Frees the memory for a persistent cursor object. */
 UNIV_INTERN

storage/innobase/include/row0mysql.h

@@ -674,9 +674,9 @@ struct row_prebuilt_struct {
 					in inserts */
 	que_fork_t*	upd_graph;	/*!< Innobase SQL query graph used
 					in updates or deletes */
-	btr_pcur_t*	pcur;		/*!< persistent cursor used in selects
+	btr_pcur_t	pcur;		/*!< persistent cursor used in selects
 					and updates */
-	btr_pcur_t*	clust_pcur;	/*!< persistent cursor used in
+	btr_pcur_t	clust_pcur;	/*!< persistent cursor used in
 					some selects and updates */
 	que_fork_t*	sel_graph;	/*!< dummy query graph used in
 					selects */

storage/innobase/row/row0mysql.c

@@ -730,8 +730,8 @@ row_create_prebuilt(
 	prebuilt->sql_stat_start = TRUE;
 	prebuilt->heap = heap;
 
-	prebuilt->pcur = btr_pcur_create_for_mysql();
-	prebuilt->clust_pcur = btr_pcur_create_for_mysql();
+	btr_pcur_reset(&prebuilt->pcur);
+	btr_pcur_reset(&prebuilt->clust_pcur);
 
 	prebuilt->select_lock_type = LOCK_NONE;
 	prebuilt->stored_select_lock_type = 99999999;
@@ -792,8 +792,8 @@ row_prebuilt_free(
 	prebuilt->magic_n = ROW_PREBUILT_FREED;
 	prebuilt->magic_n2 = ROW_PREBUILT_FREED;
 
-	btr_pcur_free_for_mysql(prebuilt->pcur);
-	btr_pcur_free_for_mysql(prebuilt->clust_pcur);
+	btr_pcur_reset(&prebuilt->pcur);
+	btr_pcur_reset(&prebuilt->clust_pcur);
 
 	if (prebuilt->mysql_template) {
 		mem_free(prebuilt->mysql_template);
@@ -1453,11 +1453,11 @@ row_update_for_mysql(
 
 	clust_index = dict_table_get_first_index(table);
 
-	if (prebuilt->pcur->btr_cur.index == clust_index) {
-		btr_pcur_copy_stored_position(node->pcur, prebuilt->pcur);
+	if (prebuilt->pcur.btr_cur.index == clust_index) {
+		btr_pcur_copy_stored_position(node->pcur, &prebuilt->pcur);
 	} else {
 		btr_pcur_copy_stored_position(node->pcur,
-					      prebuilt->clust_pcur);
+					      &prebuilt->clust_pcur);
 	}
 
 	ut_a(node->pcur->rel_pos == BTR_PCUR_ON);
@@ -1561,8 +1561,8 @@ row_unlock_for_mysql(
 					clust_pcur, and we do not need
 					to reposition the cursors. */
 {
-	btr_pcur_t*	pcur		= prebuilt->pcur;
-	btr_pcur_t*	clust_pcur	= prebuilt->clust_pcur;
+	btr_pcur_t*	pcur		= &prebuilt->pcur;
+	btr_pcur_t*	clust_pcur	= &prebuilt->clust_pcur;
 	trx_t*		trx		= prebuilt->trx;
 
 	ut_ad(prebuilt && trx);

storage/innobase/row/row0sel.c

@@ -2915,17 +2915,17 @@ row_sel_get_clust_rec_for_mysql(
 
 	btr_pcur_open_with_no_init(clust_index, prebuilt->clust_ref,
 				   PAGE_CUR_LE, BTR_SEARCH_LEAF,
-				   prebuilt->clust_pcur, 0, mtr);
+				   &prebuilt->clust_pcur, 0, mtr);
 
-	clust_rec = btr_pcur_get_rec(prebuilt->clust_pcur);
+	clust_rec = btr_pcur_get_rec(&prebuilt->clust_pcur);
 
-	prebuilt->clust_pcur->trx_if_known = trx;
+	prebuilt->clust_pcur.trx_if_known = trx;
 
 	/* Note: only if the search ends up on a non-infimum record is the
 	low_match value the real match to the search tuple */
 
 	if (!page_rec_is_user_rec(clust_rec)
-	    || btr_pcur_get_low_match(prebuilt->clust_pcur)
+	    || btr_pcur_get_low_match(&prebuilt->clust_pcur)
 	    < dict_index_get_n_unique(clust_index)) {
 
 		/* In a rare case it is possible that no clust rec is found
@@ -2974,7 +2974,7 @@ row_sel_get_clust_rec_for_mysql(
 		we set a LOCK_REC_NOT_GAP type lock */
 
 		err = lock_clust_rec_read_check_and_lock(
-			0, btr_pcur_get_block(prebuilt->clust_pcur),
+			0, btr_pcur_get_block(&prebuilt->clust_pcur),
 			clust_rec, clust_index, *offsets,
 			prebuilt->select_lock_type, LOCK_REC_NOT_GAP, thr);
 		switch (err) {
@@ -3052,7 +3052,7 @@ func_exit:
 		/* We may use the cursor in update or in unlock_row():
 		store its position */
 
-		btr_pcur_store_position(prebuilt->clust_pcur, mtr);
+		btr_pcur_store_position(&prebuilt->clust_pcur, mtr);
 	}
 
 err_exit:
@@ -3300,7 +3300,7 @@ row_sel_try_search_shortcut_for_mysql(
 {
 	dict_index_t*	index		= prebuilt->index;
 	const dtuple_t*	search_tuple	= prebuilt->search_tuple;
-	btr_pcur_t*	pcur		= prebuilt->pcur;
+	btr_pcur_t*	pcur		= &prebuilt->pcur;
 	trx_t*		trx		= prebuilt->trx;
 	const rec_t*	rec;
 
@@ -3389,7 +3389,7 @@ row_search_for_mysql(
 	dict_index_t*	index		= prebuilt->index;
 	ibool		comp		= dict_table_is_comp(index->table);
 	const dtuple_t*	search_tuple	= prebuilt->search_tuple;
-	btr_pcur_t*	pcur		= prebuilt->pcur;
+	btr_pcur_t*	pcur		= &prebuilt->pcur;
 	trx_t*		trx		= prebuilt->trx;
 	dict_index_t*	clust_index;
 	que_thr_t*	thr;