Many files:

  Push the patch of Jan Lindstrom: better comments
ha_innodb.cc:
  Partial fix for Bug #12263 : we let InnoDB always to perform a rollback on the trx object if MySQL closes a connection; but we do print a warning to the .err log if an InnoDB transaction was active; we may remove that print later, since the situation really is not a bug; MySQL just is not aware that some cursor operation started an InnoDB transaction


sql/ha_innodb.cc:
  Partial fix for Bug #12263 : we let InnoDB always to perform a rollback on the trx object if MySQL closes a connection; but we do print a warning to the .err log if an InnoDB transaction was active; we may remove that print later, since the situation really is not a bug; MySQL just is not aware that some cursor operation started an InnoDB transaction
sql/ha_innodb.h:
  Push the patch of Jan Lindstrom: better comments
innobase/trx/trx0trx.c:
  Push the patch of Jan Lindstrom: better comments
innobase/srv/srv0srv.c:
  Push the patch of Jan Lindstrom: better comments
innobase/srv/srv0start.c:
  Push the patch of Jan Lindstrom: better comments
innobase/row/row0sel.c:
  Push the patch of Jan Lindstrom: better comments
innobase/read/read0read.c:
  Push the patch of Jan Lindstrom: better comments
innobase/include/read0read.h:
  Push the patch of Jan Lindstrom: better comments
innobase/include/trx0trx.h:
  Push the patch of Jan Lindstrom: better comments

7 files changed, 39 insertions, 32 deletions

diff --git a/innobase/include/read0read.h b/innobase/include/read0read.h
index 1a7a86470a8..b5edcefb544 100644
--- a/innobase/include/read0read.h
+++ b/innobase/include/read0read.h
@@ -68,7 +68,6 @@ void
 read_view_print(
 /*============*/
 	read_view_t*	view);	/* in: read view */
-
 /*************************************************************************
 Create a consistent cursor view for mysql to be used in cursors. In this 
 consistent read view modifications done by the creating transaction or future
@@ -78,10 +77,9 @@ cursor_view_t*
 read_cursor_view_create_for_mysql(
 /*==============================*/
 	trx_t*		cr_trx);/* in: trx where cursor view is created */
-
 /*************************************************************************
-Close a given consistent cursor view for and restore global read view
-back to a transaction. */
+Close a given consistent cursor view for mysql and restore global read view
+back to a transaction read view. */
 
 void
 read_cursor_view_close_for_mysql(
@@ -90,7 +88,7 @@ read_cursor_view_close_for_mysql(
 	cursor_view_t*	curview);	/* in: cursor view to be closed */
 /*************************************************************************
 This function sets a given consistent cursor view to a transaction
-read view if given consistent cursor view is not null. Otherwice, function
+read view if given consistent cursor view is not NULL. Otherwise, function
 restores a global read view to a transaction read view. */
 
 void 
diff --git a/innobase/include/trx0trx.h b/innobase/include/trx0trx.h
index 2fc4d5a289f..a3ef755348c 100644
--- a/innobase/include/trx0trx.h
+++ b/innobase/include/trx0trx.h
@@ -606,14 +606,13 @@ struct trx_struct{
 					/* memory heap for the global read 
 					view */
 	read_view_t*	global_read_view;
-					/* consistent read view used in the
-					transaction is stored here if
-					transaction is using a consistent
-					read view associated to a cursor */
+					/* consistent read view associated
+					to a transaction or NULL */
 	read_view_t*	read_view;	/* consistent read view used in the
 					transaction or NULL, this read view
-					can be normal read view associated
-					to a transaction or read view
+					if defined can be normal read view 
+					associated to a transaction (i.e. 
+					same as global_read_view) or read view
 					associated to a cursor */
 	/*------------------------------*/
 	UT_LIST_BASE_NODE_T(trx_named_savept_t) 
diff --git a/innobase/read/read0read.c b/innobase/read/read0read.c
index 76df7cdbee0..334f9a8a85a 100644
--- a/innobase/read/read0read.c
+++ b/innobase/read/read0read.c
@@ -347,8 +347,8 @@ read_cursor_view_create_for_mysql(
 }
 
 /*************************************************************************
-Close a given consistent cursor view for and restore global read view
-back to a transaction. */
+Close a given consistent cursor view for mysql and restore global read view
+back to a transaction read view. */
 
 void
 read_cursor_view_close_for_mysql(
@@ -372,7 +372,7 @@ read_cursor_view_close_for_mysql(
 	
 /*************************************************************************
 This function sets a given consistent cursor view to a transaction
-read view if given consistent cursor view is not null. Otherwice, function
+read view if given consistent cursor view is not NULL. Otherwise, function
 restores a global read view to a transaction read view. */
 
 void 
diff --git a/innobase/row/row0sel.c b/innobase/row/row0sel.c
index 0b563eb147e..15881cb8c5d 100644
--- a/innobase/row/row0sel.c
+++ b/innobase/row/row0sel.c
@@ -3100,6 +3100,13 @@ row_search_for_mysql(
 "http://dev.mysql.com/doc/mysql/en/InnoDB_troubleshooting_datadict.html\n"
 "InnoDB: how you can resolve the problem.\n",
 				prebuilt->table->name);
+
+		/* Restore a global read view back to a transaction. This 
+		forces MySQL always to set a cursor view before fetch from
+		a cursor. */
+
+		trx->read_view = trx->global_read_view;
+
 		return(DB_ERROR);
 	}
 
@@ -4091,8 +4098,9 @@ normal_return:
 	}
 
 func_exit:
-	/* Restore a global read view back to transaction. This forces
-	MySQL always to set cursor view before fetch if it is used. */
+	/* Restore a global read view back to a transaction. This 
+	forces MySQL always to set a cursor view before fetch from
+	a cursor. */
 
 	trx->read_view = trx->global_read_view;
 
diff --git a/innobase/srv/srv0srv.c b/innobase/srv/srv0srv.c
index 837c5be2bb6..dc85750f0be 100644
--- a/innobase/srv/srv0srv.c
+++ b/innobase/srv/srv0srv.c
@@ -1711,6 +1711,10 @@ srv_printf_innodb_monitor(
 	fprintf(file, "%ld queries inside InnoDB, %lu queries in queue\n",
        		       (long) srv_conc_n_threads,
 		       (ulong) srv_conc_n_waiting_threads);
+
+	fprintf(file, "%lu read views open inside InnoDB\n",
+			UT_LIST_GET_LEN(trx_sys->view_list));
+
         n_reserved = fil_space_get_n_reserved_extents(0);
         if (n_reserved > 0) {
                 fprintf(file,
diff --git a/innobase/srv/srv0start.c b/innobase/srv/srv0start.c
index 7798e0c8e32..ffe4ba08ee9 100644
--- a/innobase/srv/srv0start.c
+++ b/innobase/srv/srv0start.c
@@ -1833,6 +1833,16 @@ innobase_shutdown_for_mysql(void)
 	srv_free();
 	os_sync_free();
 
+	/* Check that all read views are closed except read view owned
+	by a purge. */
+
+	if (UT_LIST_GET_LEN(trx_sys->view_list) > 1) {
+	        fprintf(stderr,
+"InnoDB: Error: all read views were not closed before shutdown:\n"
+"InnoDB: %lu read views open \n",
+		UT_LIST_GET_LEN(trx_sys->view_list) - 1);
+	}
+
 	/* 5. Free all allocated memory and the os_fast_mutex created in
 	ut0mem.c */
 
diff --git a/innobase/trx/trx0trx.c b/innobase/trx/trx0trx.c
index f95491443ee..1681bed9af2 100644
--- a/innobase/trx/trx0trx.c
+++ b/innobase/trx/trx0trx.c
@@ -833,26 +833,14 @@ trx_commit_off_kernel(
 
 	lock_release_off_kernel(trx);
 
-	if (trx->read_view) {
-		/* If transaction has a global read view this case
-		means that transaction has been using a consistent
-		read view associated to a cursor. Only the global
-		read view associated to a transaction is closed
-		and read view is then removed from the transaction.
-		If read view associated to a cursor is still used
-		it must be re-registered to another transaction. */
-
-		if (UNIV_LIKELY_NULL(trx->global_read_view)) {
-			trx->read_view = trx->global_read_view;
-		}
-
-		read_view_close(trx->read_view);
-
+	if (trx->global_read_view) {
+		read_view_close(trx->global_read_view);
 		mem_heap_empty(trx->global_read_view_heap);
-		trx->read_view = NULL;
 		trx->global_read_view = NULL;
 	}
 
+	trx->read_view = NULL;
+
 	if (must_flush_log) {
 
 		mutex_exit(&kernel_mutex);