Port r146 from branches/5.0:

Make innodb_flush_log_at_trx_commit a settable global variable.

handler/ha_innodb.cc

@@ -164,7 +164,6 @@ char*	innobase_unix_file_flush_method		= NULL;
 /* Below we have boolean-valued start-up parameters, and their default
 values */
 
-uint	innobase_flush_log_at_trx_commit	= 1;
 ulong	innobase_fast_shutdown			= 1;
 my_bool innobase_log_archive			= FALSE;/* unused */
 my_bool innobase_use_doublewrite    = TRUE;
@@ -1362,7 +1361,6 @@ innobase_init(void)
 	srv_log_archive_on = (ulint) innobase_log_archive;
 #endif /* UNIV_LOG_ARCHIVE */
 	srv_log_buffer_size = (ulint) innobase_log_buffer_size;
-	srv_flush_log_at_trx_commit = (ulint) innobase_flush_log_at_trx_commit;
 
         /* We set srv_pool_size here in units of 1 kB. InnoDB internally
         changes the value so that it becomes the number of database pages. */
@@ -1837,7 +1835,7 @@ innobase_commit_complete(
 
                 trx->active_trans = 0;
 
-                if (srv_flush_log_at_trx_commit == 0) {
+                if (UNIV_UNLIKELY(srv_flush_log_at_trx_commit == 0)) {
 
                         return(0);
                 }

handler/ha_innodb.h

@@ -208,7 +208,6 @@ class ha_innobase: public handler
 };
 
 extern struct show_var_st innodb_status_variables[];
-extern uint innobase_flush_log_at_trx_commit;
 extern ulong innobase_fast_shutdown;
 extern ulong innobase_large_page_size;
 extern long innobase_mirrored_log_groups, innobase_log_files_in_group;
@@ -244,6 +243,7 @@ extern ulong srv_n_free_tickets_to_enter;
 extern ulong srv_thread_sleep_delay;
 extern ulong srv_thread_concurrency;
 extern ulong srv_commit_concurrency;
+extern ulong srv_flush_log_at_trx_commit;
 }
 
 bool innobase_init(void);

include/srv0srv.h

@@ -77,7 +77,7 @@ extern ulint	srv_n_log_groups;
 extern ulint	srv_n_log_files;
 extern ulint	srv_log_file_size;
 extern ulint	srv_log_buffer_size;
-extern ulint	srv_flush_log_at_trx_commit;
+extern ulong	srv_flush_log_at_trx_commit;
 
 extern byte	srv_latin1_ordering[256];/* The sort order table of the latin1
 					character set */

srv/srv0srv.c

@@ -113,7 +113,7 @@ ulint	srv_n_log_groups	= ULINT_MAX;
 ulint	srv_n_log_files		= ULINT_MAX;
 ulint	srv_log_file_size	= ULINT_MAX;	/* size in database pages */ 
 ulint	srv_log_buffer_size	= ULINT_MAX;	/* size in database pages */ 
-ulint	srv_flush_log_at_trx_commit = 1;
+ulong	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