Merge with 3.23.53

Docs/manual.texi:
  Auto merged
innobase/include/srv0srv.h:
  Auto merged
innobase/os/os0file.c:
  Auto merged
innobase/row/row0mysql.c:
  Auto merged
innobase/srv/srv0srv.c:
  Auto merged
sql/sql_table.cc:
  Auto merged
sql/filesort.cc:
  merge

Docs/manual.texi

@@ -51223,8 +51223,14 @@ not yet 100% confident in this code.
 @appendixsubsec Changes in release 3.23.53
 @itemize @bullet
 @item
+Fixed bug in @code{ALTER TABLE} and @code{RENAME TABLE} when running with
+@code{-O lower_case_table_names=1} (typically on windows) when giving the
+table name in uppercase.
+@item
+Fixed unlikely core dump with @code{SELECT ... ORDER BY ... LIMIT}.
+@item
 Changed @code{AND/OR} to report that they can return NULL. This fixes a
-bug in @code{GROUP BY} on @code{AND/OR} expression that return
+bug in @code{GROUP BY} on @code{AND/OR} expressions that return
 @code{NULL}.
 @item
 Fixed a bug that @code{OPTIMIZE} of locked and modified MyISAM table,

innobase/include/srv0srv.h

@@ -53,7 +53,7 @@ extern ulint	srv_n_log_files;
 extern ulint	srv_log_file_size;
 extern ibool	srv_log_archive_on;
 extern ulint	srv_log_buffer_size;
-extern ibool	srv_flush_log_at_trx_commit;
+extern ulint	srv_flush_log_at_trx_commit;
 
 extern byte	srv_latin1_ordering[256];/* The sort order table of the latin1
 					character set */

innobase/os/os0file.c

@@ -15,8 +15,6 @@ Created 10/21/1995 Heikki Tuuri
 
 #undef HAVE_FDATASYNC
 
-#undef UNIV_NON_BUFFERED_IO
-
 #ifdef POSIX_ASYNC_IO
 /* We assume in this case that the OS has standard Posix aio (at least SunOS
 2.6, HP-UX 11i and AIX 4.3 have) */
@@ -500,14 +498,25 @@ os_file_create(
 		}
 #endif			
 #ifdef UNIV_NON_BUFFERED_IO
-		attributes = attributes | FILE_FLAG_NO_BUFFERING;
+		if (type == OS_LOG_FILE && srv_flush_log_at_trx_commit == 2) {
+		        /* Do not use unbuffered i/o to log files because
+		        value 2 denotes that we do not flush the log at every
+		        commit, but only once per second */
+		} else {
+		        attributes = attributes | FILE_FLAG_NO_BUFFERING;
+		}
 #endif
 	} else if (purpose == OS_FILE_NORMAL) {
-		attributes = 0
+	        attributes = 0;
 #ifdef UNIV_NON_BUFFERED_IO
-			 | FILE_FLAG_NO_BUFFERING
+		if (type == OS_LOG_FILE && srv_flush_log_at_trx_commit == 2) {
+		        /* Do not use unbuffered i/o to log files because
+		        value 2 denotes that we do not flush the log at every
+		        commit, but only once per second */
+		} else {
+		        attributes = attributes | FILE_FLAG_NO_BUFFERING;
+		}
 #endif
-			;
 	} else {
 		attributes = 0;
 		ut_error;

innobase/row/row0mysql.c

@@ -1186,7 +1186,12 @@ row_create_table_for_mysql(
 	ut_ad(trx->mysql_thread_id == os_thread_get_curr_id());
 	ut_ad(mutex_own(&(dict_sys->mutex)));
 	
-	if (srv_created_new_raw || srv_force_recovery) {
+	/* We allow a create table also if innodb_force_recovery is used. This
+        enables the user to stop a runaway rollback or a crash caused by
+	a temporary table #sql... He can use the trick explained in the
+	manual to rename the temporary table to rsql..., and then drop it. */
+
+	if (srv_created_new_raw) {
 		fprintf(stderr,
 		"InnoDB: A new raw disk partition was initialized or\n"
 		"InnoDB: innodb_force_recovery is on: we do not allow\n"
@@ -1707,7 +1712,13 @@ row_drop_table_for_mysql(
 	ut_ad(trx->mysql_thread_id == os_thread_get_curr_id());
 	ut_a(name != NULL);
 
-	if (srv_created_new_raw || srv_force_recovery) {
+	/* Note that we allow dropping of a table even if innodb_force_recovery
+        is used. If a rollback or purge would crash because of a corrupt
+        table, the user can try dropping it to avoid the crash. This is also
+        a nice way to stop a runaway rollback caused by a failing big
+        table import in a single transaction. */
+
+	if (srv_created_new_raw) {
 		fprintf(stderr,
 		"InnoDB: A new raw disk partition was initialized or\n"
 		"InnoDB: innodb_force_recovery is on: we do not allow\n"

innobase/srv/srv0srv.c

@@ -96,7 +96,7 @@ ulint	srv_n_log_files		= ULINT_MAX;
 ulint	srv_log_file_size	= ULINT_MAX;	/* size in database pages */ 
 ibool	srv_log_archive_on	= TRUE;
 ulint	srv_log_buffer_size	= ULINT_MAX;	/* size in database pages */ 
-ibool	srv_flush_log_at_trx_commit = TRUE;
+ulint	srv_flush_log_at_trx_commit = 1;
 
 byte	srv_latin1_ordering[256]	/* The sort order table of the latin1
 					character set. The following table is