MDEV-13807 mariabackup --apply-log-only does generate redo log by performing rollback and possibly other tasks

Skip rollback and other redo-log-generating tasks if
srv_apply_log_only is set.

Instead of assigning the debug variable recv_no_log_write = FALSE,
assign it to srv_apply_log_only, so that any unwanted writes are caught.

mysql-test/suite/mariabackup/apply-log-only-incr.result

@@ -0,0 +1,29 @@
+call mtr.add_suppression("InnoDB: New log files created");
+CREATE TABLE t(a INT UNSIGNED PRIMARY KEY) ENGINE INNODB;
+INSERT INTO t VALUES(0);
+COMMIT;
+start transaction;
+NOT FOUND /Rollback of trx with id/ in current_test
+# expect NOT FOUND
+NOT FOUND /Rollback of trx with id/ in current_test
+# expect NOT FOUND
+commit;
+SELECT count(*) FROM t;
+count(*)
+201
+# Restore and check results
+# shutdown server
+# remove datadir
+# xtrabackup move back
+# restart server
+SELECT COUNT(*) FROM t;
+COUNT(*)
+1
+SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED;
+SELECT COUNT(*) FROM t;
+COUNT(*)
+201
+SELECT * FROM t;
+a
+0
+DROP TABLE t;

mysql-test/suite/mariabackup/apply-log-only-incr.test

@@ -0,0 +1,62 @@
+--source include/have_innodb.inc
+
+call mtr.add_suppression("InnoDB: New log files created");
+
+let $basedir=$MYSQLTEST_VARDIR/tmp/backup;
+let $incremental_dir=$MYSQLTEST_VARDIR/tmp/backup_inc1;
+
+CREATE TABLE t(a INT UNSIGNED PRIMARY KEY) ENGINE INNODB;
+INSERT INTO t VALUES(0);
+COMMIT;
+
+start transaction;
+--disable_query_log
+let $n=100;
+while ($n) {
+eval INSERT t VALUES(101-$n);
+dec $n;
+}
+
+--disable_result_log
+exec $XTRABACKUP --defaults-file=$MYSQLTEST_VARDIR/my.cnf  --backup --target-dir=$basedir;
+--enable_result_log
+let $n=100;
+while ($n) {
+eval INSERT t VALUES(201-$n);
+dec $n;
+}
+--enable_query_log
+
+--disable_result_log
+exec $XTRABACKUP --defaults-file=$MYSQLTEST_VARDIR/my.cnf  --backup --ftwrl-wait-timeout=5 --ftwrl-wait-threshold=300 --ftwrl-wait-query-type=all --target-dir=$incremental_dir --incremental-basedir=$basedir ;
+exec $XTRABACKUP --prepare --apply-log-only --target-dir=$basedir ;
+--enable_result_log
+
+let SEARCH_FILE=$MYSQLTEST_VARDIR/log/current_test;
+--let SEARCH_PATTERN= Rollback of trx with id
+--source include/search_pattern_in_file.inc
+--echo # expect NOT FOUND
+
+exec $XTRABACKUP --prepare --apply-log-only --target-dir=$basedir --incremental-dir=$incremental_dir ;
+
+--source include/search_pattern_in_file.inc
+--echo # expect NOT FOUND
+
+commit;
+SELECT count(*) FROM t;
+echo # Restore and check results;
+--let $targetdir=$basedir
+--let $restart_parameters= --innodb-force-recovery=3
+--source include/restart_and_restore.inc
+
+rmdir $basedir;
+
+SELECT COUNT(*) FROM t;
+SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED;
+SELECT COUNT(*) FROM t;
+
+--let $restart_parameters=
+--source include/restart_mysqld.inc
+
+SELECT * FROM t;
+DROP TABLE t;

mysql-test/suite/mariabackup/apply-log-only.result

@@ -0,0 +1,10 @@
+call mtr.add_suppression("InnoDB: New log files created");
+CREATE TABLE t(a varchar(60)) ENGINE INNODB;
+start transaction;
+INSERT INTO t VALUES(1);
+NOT FOUND /Rollback of trx with id/ in current_test
+# expect NOT FOUND
+SELECT count(*) FROM t;
+count(*)
+1
+DROP TABLE t;

mysql-test/suite/mariabackup/apply-log-only.test

@@ -0,0 +1,25 @@
+--source include/have_innodb.inc
+call mtr.add_suppression("InnoDB: New log files created");
+
+let $basedir=$MYSQLTEST_VARDIR/tmp/backup;
+
+CREATE TABLE t(a varchar(60)) ENGINE INNODB;
+start transaction;
+INSERT INTO t VALUES(1);
+
+--disable_result_log
+exec $XTRABACKUP --defaults-file=$MYSQLTEST_VARDIR/my.cnf  --backup --target-dir=$basedir;
+--enable_result_log
+
+exec $XTRABACKUP --prepare --apply-log-only --target-dir=$basedir ;
+
+let SEARCH_FILE=$MYSQLTEST_VARDIR/log/current_test;
+--let SEARCH_PATTERN= Rollback of trx with id
+--source include/search_pattern_in_file.inc
+--echo # expect NOT FOUND
+
+SELECT count(*) FROM t;
+DROP TABLE t;
+
+# Cleanup
+rmdir $basedir;

storage/xtradb/log/log0recv.cc

@@ -1980,7 +1980,7 @@ recv_apply_hashed_log_recs(bool last_batch)
 
 		mutex_enter(&(log_sys->mutex));
 		mutex_enter(&(recv_sys->mutex));
-		ut_d(recv_no_log_write = FALSE);
+		ut_d(recv_no_log_write = srv_apply_log_only);
 
 		recv_no_ibuf_operations = FALSE;
 	}
@@ -3461,7 +3461,8 @@ recv_recovery_from_checkpoint_finish(void)
 	that the data dictionary tables will be free of any locks.
 	The data dictionary latch should guarantee that there is at
 	most one data dictionary transaction active at a time. */
-	if (srv_force_recovery < SRV_FORCE_NO_TRX_UNDO) {
+	if (srv_force_recovery < SRV_FORCE_NO_TRX_UNDO
+	    && !srv_apply_log_only) {
 		trx_rollback_or_clean_recovered(FALSE);
 	}
 }

storage/xtradb/srv/srv0srv.cc

@@ -2470,7 +2470,7 @@ srv_get_active_thread_type(void)
 {
 	srv_thread_type ret = SRV_NONE;
 
-	if (srv_read_only_mode) {
+	if (srv_read_only_mode || srv_apply_log_only) {
 		return(SRV_NONE);
 	}
 

storage/xtradb/srv/srv0start.cc

@@ -767,7 +767,7 @@ create_log_files(
 
 	/* Create a log checkpoint. */
 	mutex_enter(&log_sys->mutex);
-	ut_d(recv_no_log_write = FALSE);
+	ut_d(recv_no_log_write = srv_apply_log_only);
 	recv_reset_logs(
 #ifdef UNIV_LOG_ARCHIVE
 		UT_LIST_GET_FIRST(log_sys->log_groups)->archived_file_no,
@@ -2748,6 +2748,11 @@ files_checked:
 
 		recv_recovery_from_checkpoint_finish();
 
+		if (srv_apply_log_only) {
+			ut_ad(IS_XTRABACKUP());
+			goto skip_processes;
+		}
+
 		if (srv_force_recovery < SRV_FORCE_NO_IBUF_MERGE) {
 			/* The following call is necessary for the insert
 			buffer to work with multiple tablespaces. We must
@@ -3156,6 +3161,7 @@ files_checked:
 		os_thread_create(btr_defragment_thread, NULL, NULL);
 	}
 
+skip_processes:
 	srv_was_started = TRUE;
 
 	return(DB_SUCCESS);
@@ -3318,7 +3324,7 @@ innodb_shutdown()
 		srv_misc_tmpfile = 0;
 	}
 
-	if (!srv_read_only_mode) {
+	if (!srv_read_only_mode && !srv_apply_log_only) {
 		dict_stats_thread_deinit();
 		fil_crypt_threads_cleanup();
 		btr_scrub_cleanup();

storage/xtradb/trx/trx0rseg.cc

@@ -122,9 +122,11 @@ trx_rseg_mem_free(
 
 	mutex_free(&rseg->mutex);
 
+	if (!srv_apply_log_only) {
 	/* There can't be any active transactions. */
 	ut_a(UT_LIST_GET_LEN(rseg->update_undo_list) == 0);
 	ut_a(UT_LIST_GET_LEN(rseg->insert_undo_list) == 0);
+	}
 
 	for (undo = UT_LIST_GET_FIRST(rseg->update_undo_cached);
 	     undo != NULL;

storage/xtradb/trx/trx0sys.cc

@@ -1346,8 +1346,7 @@ trx_sys_close(void)
 	ut_a(UT_LIST_GET_LEN(trx_sys->rw_trx_list) == trx_sys->n_prepared_trx
 	     || srv_read_only_mode
 	     || srv_force_recovery >= SRV_FORCE_NO_TRX_UNDO
-	     || (IS_XTRABACKUP() && srv_apply_log_only));
-
+	     || srv_apply_log_only);
 
 	while ((trx = UT_LIST_GET_FIRST(trx_sys->rw_trx_list)) != NULL) {
 		trx_free_prepared(trx);
@@ -1378,7 +1377,7 @@ trx_sys_close(void)
 		UT_LIST_REMOVE(view_list, trx_sys->view_list, prev_view);
 	}
 
-	if (!IS_XTRABACKUP() || !srv_apply_log_only) {
+	if (!srv_apply_log_only) {
 		ut_a(UT_LIST_GET_LEN(trx_sys->view_list) == 0);
 		ut_a(UT_LIST_GET_LEN(trx_sys->ro_trx_list) == 0);
 		ut_a(UT_LIST_GET_LEN(trx_sys->rw_trx_list) == 0);
@@ -1430,7 +1429,7 @@ ulint
 trx_sys_any_active_transactions(void)
 /*=================================*/
 {
-	if (IS_XTRABACKUP() && srv_apply_log_only) {
+	if (srv_apply_log_only) {
 		return(0);
 	}
 	mutex_enter(&trx_sys->mutex);

storage/xtradb/trx/trx0trx.cc

@@ -483,6 +483,7 @@ trx_free_prepared(
 	     || (trx_state_eq(trx, TRX_STATE_ACTIVE)
 		 && trx->is_recovered
 		 && (srv_read_only_mode
+		     || srv_apply_log_only
 		     || srv_force_recovery >= SRV_FORCE_NO_TRX_UNDO)));
 	ut_a(trx->magic_n == TRX_MAGIC_N);
 

storage/xtradb/trx/trx0undo.cc

@@ -2037,6 +2037,7 @@ trx_undo_free_prepared(
 			/* lock_trx_release_locks() assigns
 			trx->is_recovered=false */
 			ut_a(srv_read_only_mode
+			     || srv_apply_log_only
 			     || srv_force_recovery >= SRV_FORCE_NO_TRX_UNDO);
 			break;
 		default: