Adapt the innodb_undo tests from MySQL 5.7

Simplify the tests that are present in MySQL 5.7. Make the table
smaller while generating enough undo log. Do not unnecessarily
drop tables.

trx_purge_initiate_truncate(): Remove two crash injection points
(before and after normal redo log checkpoint), because they are
not adding any value. Clarify some messages.

trx_sys_create_rsegs(): Display the number of active undo tablespaces.

srv_undo_tablespaces_init(): When initializing the data files, do not
leave srv_undo_tablespaces_active at 0.
Do not display that number; let trx_sys_create_rsegs() display it once
the final number is known.

innodb_params_adjust(): Adjust parameters after startup.

innobase_init(): Do not allow innodb_max_undo_size to be less
than SRV_UNDO_TABLESPACE_SIZE_IN_PAGES. This avoids unnecessary
repeated truncation of undo tablespaces when using
innodb_page_size=32k or innodb_page_size=64k.

mysql-test/include/have_innodb_max_16k.inc

+if (`SELECT COUNT(*) = 0 FROM INFORMATION_SCHEMA.GLOBAL_STATUS WHERE LOWER(variable_name) = 'innodb_page_size' AND variable_value <= 16384`)
+{
+  --skip Test requires InnoDB with page size not greater than 16k.
+}

mysql-test/suite/innodb_undo/include/have_undo_tablespaces.inc

+if (`select count(*) = 0 from information_schema.global_variables where variable_name like 'innodb_undo_tablespaces' and variable_value >= 2`)
+{
+  --skip Test requires InnoDB with at-least 2 undo tablespaces.
+}

mysql-test/suite/innodb_undo/include/truncate_recover.inc

+begin;
+update t1 set c = 'MariaDB';
+update t1 set c = 'InnoDB';
+eval set global debug_dbug = '+d,$SEARCH_PATTERN';
+commit;
+--source include/shutdown_mysqld.inc
+--source include/search_pattern_in_file.inc
+--source include/start_mysqld.inc

mysql-test/suite/innodb_undo/r/truncate.result

+SET GLOBAL innodb_fast_shutdown=0;
+create table t1(keyc int primary key, c1 char(100)) engine = innodb;
+begin;
+update t1 set c1 = 'mysql';
+update t1 set c1 = 'oracle';
+delete from t1;
+commit;
+drop table t1;
+SET GLOBAL innodb_fast_shutdown=0;
+SET GLOBAL innodb_undo_log_truncate=1;
+SET GLOBAL innodb_purge_rseg_truncate_frequency=1;

mysql-test/suite/innodb_undo/r/truncate_multi_client.result

+SET GLOBAL innodb_fast_shutdown=0;
+create table t1(keyc int primary key, c char(100)) engine = innodb;
+create table t2(keyc int primary key, c char(100)) engine = innodb;
+CREATE PROCEDURE populate_t1()
+BEGIN
+DECLARE i INT DEFAULT 1;
+while (i <= 20000) DO
+insert into t1 values (i, 'a');
+SET i = i + 1;
+END WHILE;
+END |
+CREATE PROCEDURE populate_t2()
+BEGIN
+DECLARE i INT DEFAULT 1;
+while (i <= 20000) DO
+insert into t2 values (i, 'a');
+SET i = i + 1;
+END WHILE;
+END |
+connect  con1,localhost,root,,;
+begin;
+call populate_t1();
+connect  con2,localhost,root,,;
+begin;
+call populate_t2();
+connection con1;
+update t1 set c = 'mysql';
+connection con2;
+update t2 set c = 'mysql';
+connection con1;
+update t1 set c = 'oracle';
+connection con2;
+update t2 set c = 'oracle';
+connection con1;
+delete from t1;
+connection con2;
+delete from t2;
+connection con1;
+commit;
+disconnect con1;
+connection con2;
+commit;
+disconnect con2;
+connection default;
+drop table t1, t2;
+drop PROCEDURE populate_t1;
+drop PROCEDURE populate_t2;
+SET GLOBAL innodb_fast_shutdown=0;
+SET GLOBAL innodb_undo_log_truncate=1;
+SET GLOBAL innodb_purge_rseg_truncate_frequency=1;
+FOUND 1 /Truncating UNDO tablespace 1/ in mysqld.1.err

mysql-test/suite/innodb_undo/r/truncate_recover.result

+create table t1(keyc int primary key, c char(100)) engine = innodb;
+begin;
+commit;
+begin;
+update t1 set c = 'MariaDB';
+update t1 set c = 'InnoDB';
+set global debug_dbug = '+d,ib_undo_trunc_before_truncate';
+commit;
+FOUND 1 /ib_undo_trunc_before_truncate/ in mysqld.1.err
+begin;
+update t1 set c = 'MariaDB';
+update t1 set c = 'InnoDB';
+set global debug_dbug = '+d,ib_undo_trunc_before_ddl_log_end';
+commit;
+FOUND 1 /ib_undo_trunc_before_ddl_log_end/ in mysqld.1.err

mysql-test/suite/innodb_undo/t/truncate.test

+#
+# WL#6965: Truncate UNDO logs.
+#
+
+--source include/have_innodb.inc
+--source include/have_innodb_max_16k.inc
+--source include/have_undo_tablespaces.inc
+
+# The test is restarting the server to force undo truncation.
+--source include/not_embedded.inc
+
+SET GLOBAL innodb_fast_shutdown=0;
+--let $restart_parameters=--innodb_undo_tablespaces=2 --innodb_undo_logs=4
+--source include/restart_mysqld.inc
+
+let MYSQLD_DATADIR = `select @@datadir`;
+
+#-----------------------------------------------------------------------------
+#
+# 1. Perform enough DML action so that undo tablespace size grows beyond
+#    set threshold and then wait and see if it is being truncated.
+#
+create table t1(keyc int primary key, c1 char(100)) engine = innodb;
+begin;
+--disable_query_log
+let $i=30000;
+while ($i) {
+  eval insert into t1 values(30000-$i, '');
+  dec $i;
+}
+--enable_query_log
+update t1 set c1 = 'mysql';
+update t1 set c1 = 'oracle';
+delete from t1;
+commit;
+drop table t1;
+
+let CHECKFILE = $MYSQL_TMP_DIR/check.txt;
+perl;
+($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size1)
+	= stat("$ENV{MYSQLD_DATADIR}/undo001");
+($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size2)
+	= stat("$ENV{MYSQLD_DATADIR}/undo002");
+open(OUT, ">$ENV{CHECKFILE}") || die;
+print OUT "let \$size1='$size1,$size2';\n";
+close(OUT);
+EOF
+SET GLOBAL innodb_fast_shutdown=0;
+SET GLOBAL innodb_undo_log_truncate=1;
+SET GLOBAL innodb_purge_rseg_truncate_frequency=1;
+--source include/shutdown_mysqld.inc
+--source $CHECKFILE
+perl;
+($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size1)
+	= stat("$ENV{MYSQLD_DATADIR}/undo001");
+($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size2)
+	= stat("$ENV{MYSQLD_DATADIR}/undo002");
+open(OUT, ">$ENV{CHECKFILE}") || die;
+print OUT "let \$size2='$size1,$size2';\n";
+close(OUT);
+EOF
+
+--source $CHECKFILE
+--remove_file $CHECKFILE
+
+if ($size1 == $size2)
+{
+   echo Truncation did not happen: $size1 == $size2;
+}
+
+--let $restart_parameters=
+--source include/start_mysqld.inc

mysql-test/suite/innodb_undo/t/truncate_multi_client.test

+#
+# WL#6965: Truncate UNDO logs.
+#
+
+--source include/have_innodb.inc
+# This test is restarting the server.
+--source include/not_embedded.inc
+# With larger innodb_page_size, the undo log tablespaces do not grow enough.
+--source include/have_innodb_max_16k.inc
+--source include/have_undo_tablespaces.inc
+
+SET GLOBAL innodb_fast_shutdown=0;
+--let $restart_parameters=--innodb_undo_tablespaces=2 --innodb_undo_logs=4
+--source include/restart_mysqld.inc
+
+#-----------------------------------------------------------------------------
+#
+# Perform DML action using multiple clients and multiple undo tablespace.
+#
+#
+create table t1(keyc int primary key, c char(100)) engine = innodb;
+create table t2(keyc int primary key, c char(100)) engine = innodb;
+#
+delimiter |;
+CREATE PROCEDURE populate_t1()
+BEGIN
+        DECLARE i INT DEFAULT 1;
+        while (i <= 20000) DO
+                insert into t1 values (i, 'a');
+                SET i = i + 1;
+        END WHILE;
+END |
+delimiter ;|
+#
+delimiter |;
+CREATE PROCEDURE populate_t2()
+BEGIN
+        DECLARE i INT DEFAULT 1;
+        while (i <= 20000) DO
+                insert into t2 values (i, 'a');
+                SET i = i + 1;
+        END WHILE;
+END |
+delimiter ;|
+#
+#
+connect (con1,localhost,root,,);
+begin;
+send call populate_t1();
+
+connect (con2,localhost,root,,);
+begin;
+send call populate_t2();
+
+connection con1; reap; send update t1 set c = 'mysql';
+connection con2; reap; send update t2 set c = 'mysql';
+connection con1; reap; send update t1 set c = 'oracle';
+connection con2; reap; send update t2 set c = 'oracle';
+connection con1; reap; send delete from t1;
+connection con2; reap; send delete from t2;
+connection con1; reap; commit; disconnect con1;
+connection con2; reap; commit; disconnect con2;
+
+connection default;
+drop table t1, t2;
+drop PROCEDURE populate_t1;
+drop PROCEDURE populate_t2;
+
+SET GLOBAL innodb_fast_shutdown=0;
+SET GLOBAL innodb_undo_log_truncate=1;
+SET GLOBAL innodb_purge_rseg_truncate_frequency=1;
+
+--source include/restart_mysqld.inc
+
+let SEARCH_FILE = $MYSQLTEST_VARDIR/log/mysqld.1.err;
+let SEARCH_PATTERN = Truncating UNDO tablespace 1;
+--source include/search_pattern_in_file.inc

mysql-test/suite/innodb_undo/t/truncate_recover.test

+#
+# WL#6965: Truncate UNDO logs.
+#
+
+--source include/have_innodb.inc
+--source include/have_debug.inc
+# With larger innodb_page_size, the undo log tablespaces do not grow enough.
+--source include/have_innodb_max_16k.inc
+--source include/have_undo_tablespaces.inc
+
+# Valgrind would complain about memory leaks when we crash on purpose.
+--source include/not_valgrind.inc
+# Embedded server does not support crashing
+--source include/not_embedded.inc
+# Avoid CrashReporter popup on Mac
+--source include/not_crashrep.inc
+
+--disable_query_log
+# FIXME: The doublewrite buffer should not issue these warnings.
+# FIXME: Maybe buf_dblwr_process() should empty the buffer at the end?
+call mtr.add_suppression("InnoDB: A copy of page.*in the doublewrite buffer slot.*is not within space bounds");
+FLUSH TABLES;
+--enable_query_log
+
+--let $restart_parameters=--innodb-undo-logs=4 --innodb-undo-tablespaces=2 --innodb-undo-log-truncate=1 --innodb-max-undo-log-size=10485760 --innodb-purge-rseg-truncate-frequency=1 --innodb-fast-shutdown=0
+--source include/restart_mysqld.inc
+
+let SEARCH_FILE = $MYSQLTEST_VARDIR/log/mysqld.1.err;
+
+create table t1(keyc int primary key, c char(100)) engine = innodb;
+begin;
+--disable_query_log
+let $i=30000;
+while ($i) {
+  eval insert into t1 values(30000-$i, '');
+  dec $i;
+}
+--enable_query_log
+commit;
+
+let SEARCH_PATTERN = ib_undo_trunc_before_truncate;
+--source include/truncate_recover.inc
+
+let SEARCH_PATTERN = ib_undo_trunc_before_ddl_log_end;
+--source include/truncate_recover.inc
+
+let SEARCH_PATTERN = ib_undo_trunc_trunc_done;
+let $restart_parameters=
+--source include/truncate_recover.inc
+drop table t1;

mysql-test/suite/sys_vars/r/innodb_max_undo_log_size_basic.result

@@ -4,17 +4,21 @@ COUNT(@@GLOBAL.innodb_max_undo_log_size)
 1
 1 Expected
 '#---------------------BS_STVARS_035_02----------------------#'
+SET @save = @@GLOBAL.innodb_max_undo_log_size;
 SET @@GLOBAL.innodb_max_undo_log_size=1073741824;
 SELECT COUNT(@@GLOBAL.innodb_max_undo_log_size);
 COUNT(@@GLOBAL.innodb_max_undo_log_size)
 1
 1 Expected
 SET @@GLOBAL.innodb_max_undo_log_size=18446744073709551615;
-SELECT @@GLOBAL.innodb_max_undo_log_size;
-@@GLOBAL.innodb_max_undo_log_size
-18446744073709551615
-18446744073709551615 Expected
+Warnings:
+Warning	1292	Truncated incorrect innodb_max_undo_log_size value: '18446744073709551615'
+SELECT FLOOR(@@GLOBAL.innodb_max_undo_log_size / @@GLOBAL.innodb_page_size);
+FLOOR(@@GLOBAL.innodb_max_undo_log_size / @@GLOBAL.innodb_page_size)
+4294967296
+4294967296 Expected
 SET @@GLOBAL.innodb_max_undo_log_size=1073741824;
+SET GLOBAL innodb_max_undo_log_size = @save;
 '#---------------------BS_STVARS_035_03----------------------#'
 SELECT @@GLOBAL.innodb_max_undo_log_size = VARIABLE_VALUE
 FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES

mysql-test/suite/sys_vars/r/sysvars_innodb.result

@@ -1618,14 +1618,14 @@ READ_ONLY	NO
 COMMAND_LINE_ARGUMENT	REQUIRED
 VARIABLE_NAME	INNODB_MAX_UNDO_LOG_SIZE
 SESSION_VALUE	NULL
-GLOBAL_VALUE	1073741824
+GLOBAL_VALUE	10485760
 GLOBAL_VALUE_ORIGIN	COMPILE-TIME
-DEFAULT_VALUE	1073741824
+DEFAULT_VALUE	10485760
 VARIABLE_SCOPE	GLOBAL
 VARIABLE_TYPE	BIGINT UNSIGNED
-VARIABLE_COMMENT	Maximum size of UNDO tablespace in MB (If UNDO tablespace grows beyond this size it will be truncated in due course). 
+VARIABLE_COMMENT	Desired maximum UNDO tablespace size in bytes
 NUMERIC_MIN_VALUE	10485760
-NUMERIC_MAX_VALUE	18446744073709551615
+NUMERIC_MAX_VALUE	281474976710656
 NUMERIC_BLOCK_SIZE	0
 ENUM_VALUE_LIST	NULL
 READ_ONLY	NO

mysql-test/suite/sys_vars/t/innodb_max_undo_log_size_basic.test

@@ -37,17 +37,21 @@ SELECT COUNT(@@GLOBAL.innodb_max_undo_log_size);
 #   Check if Value can set                                         #
 ####################################################################
 
+SET @save = @@GLOBAL.innodb_max_undo_log_size;
+
 SET @@GLOBAL.innodb_max_undo_log_size=1073741824;
 
 SELECT COUNT(@@GLOBAL.innodb_max_undo_log_size);
 --echo 1 Expected
 
 SET @@GLOBAL.innodb_max_undo_log_size=18446744073709551615;
-SELECT @@GLOBAL.innodb_max_undo_log_size;
---echo 18446744073709551615 Expected
+SELECT FLOOR(@@GLOBAL.innodb_max_undo_log_size / @@GLOBAL.innodb_page_size);
+--echo 4294967296 Expected
 
 SET @@GLOBAL.innodb_max_undo_log_size=1073741824;
 
+SET GLOBAL innodb_max_undo_log_size = @save;
+
 --echo '#---------------------BS_STVARS_035_03----------------------#'
 #################################################################
 # Check if the value in GLOBAL Table matches value in variable  #

storage/innobase/handler/ha_innodb.cc

@@ -1359,15 +1359,11 @@ void
 innobase_commit_concurrency_init_default();
 /*=======================================*/
 
-/** @brief Initialize the default and max value of innodb_undo_logs.
-
-Once InnoDB is running, the default value and the max value of
-innodb_undo_logs must be equal to the available undo logs,
-given by srv_available_undo_logs. */
+/** @brief Adjust some InnoDB startup parameters based on file contents
+or innodb_page_size. */
 static
 void
-innobase_undo_logs_init_default_max();
-/*==================================*/
+innodb_params_adjust();
 
 /************************************************************//**
 Validate the file format name and return its corresponding id.
@@ -4291,6 +4287,11 @@ innobase_init(
 
 	if (UNIV_PAGE_SIZE_DEF != srv_page_size) {
 		ib::info() << "innodb_page_size=" << srv_page_size;
+
+		srv_max_undo_log_size = std::max(
+			srv_max_undo_log_size,
+			ulonglong(SRV_UNDO_TABLESPACE_SIZE_IN_PAGES)
+			* srv_page_size);
 	}
 
 	if (srv_log_write_ahead_size > srv_page_size) {
@@ -4457,12 +4458,6 @@ innobase_init(
 	}
 	*/
 
-	/* Since we in this module access directly the fields of a trx
-	struct, and due to different headers and flags it might happen that
-	ib_mutex_t has a different size in this module and in InnoDB
-	modules, we check at run time that the size is the same in
-	these compilation modules. */
-
 	err = innobase_start_or_create_for_mysql();
 
 	if (srv_buf_pool_size_org != 0) {
@@ -4488,8 +4483,7 @@ innobase_init(
 	}
 
 	srv_was_started = true;
-	/* Adjust the innodb_undo_logs config object */
-	innobase_undo_logs_init_default_max();
+	innodb_params_adjust();
 
 	innobase_old_blocks_pct = static_cast<uint>(
 		buf_LRU_old_ratio_update(innobase_old_blocks_pct, TRUE));
@@ -21493,12 +21487,10 @@ static MYSQL_SYSVAR_ULONG(undo_logs, srv_undo_logs,
 
 static MYSQL_SYSVAR_ULONGLONG(max_undo_log_size, srv_max_undo_log_size,
   PLUGIN_VAR_OPCMDARG,
-  "Maximum size of UNDO tablespace in MB (If UNDO tablespace grows"
-  " beyond this size it will be truncated in due course). ",
+  "Desired maximum UNDO tablespace size in bytes",
   NULL, NULL,
-  1024 * 1024 * 1024L,
-  10 * 1024 * 1024L,
-  ~0ULL, 0);
+  10 << 20, 10 << 20,
+  1ULL << (32 + UNIV_PAGE_SIZE_SHIFT_MAX), 0);
 
 static MYSQL_SYSVAR_ULONG(purge_rseg_truncate_frequency,
   srv_purge_rseg_truncate_frequency,
@@ -22222,19 +22214,25 @@ innobase_commit_concurrency_init_default()
 		= innobase_commit_concurrency;
 }
 
-/** @brief Initialize the default and max value of innodb_undo_logs.
-
-Once InnoDB is running, the default value and the max value of
-innodb_undo_logs must be equal to the available undo logs,
-given by srv_available_undo_logs. */
+/** @brief Adjust some InnoDB startup parameters based on file contents
+or innodb_page_size. */
 static
 void
-innobase_undo_logs_init_default_max()
-/*=================================*/
+innodb_params_adjust()
 {
+	/* The default value and the max value of
+	innodb_undo_logs must be equal to the available undo logs. */
 	MYSQL_SYSVAR_NAME(undo_logs).max_val
 		= MYSQL_SYSVAR_NAME(undo_logs).def_val
 		= srv_available_undo_logs;
+	MYSQL_SYSVAR_NAME(max_undo_log_size).max_val
+		= 1ULL << (32 + UNIV_PAGE_SIZE_SHIFT);
+	MYSQL_SYSVAR_NAME(max_undo_log_size).min_val
+		= MYSQL_SYSVAR_NAME(max_undo_log_size).def_val
+		= ulonglong(SRV_UNDO_TABLESPACE_SIZE_IN_PAGES)
+		* srv_page_size;
+	MYSQL_SYSVAR_NAME(max_undo_log_size).max_val
+		= 1ULL << (32 + UNIV_PAGE_SIZE_SHIFT);
 }
 
 /****************************************************************************

storage/innobase/srv/srv0start.cc

@@ -894,6 +894,7 @@ srv_undo_tablespaces_init(bool create_new_db)
 			}
 		}
 	} else {
+		srv_undo_tablespaces_active = srv_undo_tablespaces;
 		n_undo_tablespaces = srv_undo_tablespaces;
 
 		for (i = 1; i <= n_undo_tablespaces; ++i) {
@@ -975,12 +976,10 @@ srv_undo_tablespaces_init(bool create_new_db)
 
 		return(err != DB_SUCCESS ? err : DB_ERROR);
 
-	} else  if (n_undo_tablespaces > 0) {
+	} else if (n_undo_tablespaces > 0) {
 
 		ib::info() << "Opened " << n_undo_tablespaces
-			<< " undo tablespaces ("
-			<< srv_undo_tablespaces_active
-			<< " active)";
+			<< " undo tablespaces";
 
 		if (srv_undo_tablespaces == 0) {
 			ib::warn() << "innodb_undo_tablespaces=0 disables"

storage/innobase/trx/trx0purge.cc

 /*****************************************************************************
 
 Copyright (c) 1996, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, MariaDB Corporation. All Rights Reserved.
+Copyright (c) 2017, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -987,27 +987,20 @@ trx_purge_initiate_truncate(
 	   initiate truncate.
 	d. Execute actual truncate
 	e. Remove the DDL log. */
-	DBUG_EXECUTE_IF("ib_undo_trunc_before_checkpoint",
-			ib::info() << "ib_undo_trunc_before_checkpoint";
-			DBUG_SUICIDE(););
 
 	/* After truncate if server crashes then redo logging done for this
 	undo tablespace might not stand valid as tablespace has been
 	truncated. */
 	log_make_checkpoint_at(LSN_MAX, TRUE);
 
-	ib::info() << "Truncating UNDO tablespace with space identifier "
-		<< undo_trunc->get_marked_space_id();
+	const ulint space_id = undo_trunc->get_marked_space_id();
 
-	DBUG_EXECUTE_IF("ib_undo_trunc_before_ddl_log_start",
-			ib::info() << "ib_undo_trunc_before_ddl_log_start";
-			DBUG_SUICIDE(););
+	ib::info() << "Truncating UNDO tablespace " << space_id;
 
 #ifdef UNIV_DEBUG
 	dberr_t	err =
 #endif /* UNIV_DEBUG */
-		undo_trunc->start_logging(
-			undo_trunc->get_marked_space_id());
+		undo_trunc->start_logging(space_id);
 	ut_ad(err == DB_SUCCESS);
 
 	DBUG_EXECUTE_IF("ib_undo_trunc_before_truncate",
@@ -1016,14 +1009,12 @@ trx_purge_initiate_truncate(
 
 	trx_purge_cleanse_purge_queue(undo_trunc);
 
-	bool	success = trx_undo_truncate_tablespace(undo_trunc);
-	if (!success) {
+	if (!trx_undo_truncate_tablespace(undo_trunc)) {
 		/* Note: In case of error we don't enable the rsegs
 		and neither unmark the tablespace so the tablespace
 		continue to remain inactive. */
-		ib::error() << "Failed to truncate UNDO tablespace with"
-			" space identifier "
-			<< undo_trunc->get_marked_space_id();
+		ib::error() << "Failed to truncate UNDO tablespace "
+			<< space_id;
 		return;
 	}
 
@@ -1046,7 +1037,7 @@ trx_purge_initiate_truncate(
 
 	log_make_checkpoint_at(LSN_MAX, TRUE);
 
-	undo_trunc->done_logging(undo_trunc->get_marked_space_id());
+	undo_trunc->done_logging(space_id);
 
 	/* Completed truncate. Now it is safe to re-use the tablespace. */
 	for (ulint i = 0; i < undo_trunc->rsegs_size(); ++i) {
@@ -1054,8 +1045,7 @@ trx_purge_initiate_truncate(
 		rseg->skip_allocation = false;
 	}
 
-	ib::info() << "Completed truncate of UNDO tablespace with space"
-		" identifier " << undo_trunc->get_marked_space_id();
+	ib::info() << "Truncated UNDO tablespace " << space_id;
 
 	undo_trunc->reset();
 	undo::Truncate::clear_trunc_list();
@@ -1075,7 +1065,7 @@ trx_purge_truncate_history(
 	purge_iter_t*		limit,		/*!< in: truncate limit */
 	const ReadView*		view)		/*!< in: purge view */
 {
-	ulint		i;
+	ut_ad(trx_purge_check_limit());
 
 	/* We play safe and set the truncate limit at most to the purge view
 	low_limit number, though this is not necessary */
@@ -1088,7 +1078,7 @@ trx_purge_truncate_history(
 
 	ut_ad(limit->trx_no <= purge_sys->view.low_limit_no());
 
-	for (i = 0; i < TRX_SYS_N_RSEGS; ++i) {
+	for (ulint i = 0; i < TRX_SYS_N_RSEGS; ++i) {
 		trx_rseg_t*	rseg = trx_sys->rseg_array[i];
 
 		if (rseg != NULL) {
@@ -1100,8 +1090,7 @@ trx_purge_truncate_history(
 	/* UNDO tablespace truncate. We will try to truncate as much as we
 	can (greedy approach). This will ensure when the server is idle we
 	try and truncate all the UNDO tablespaces. */
-	ulint	nchances = srv_undo_tablespaces_active;
-	for (i = 0; i < nchances; i++) {
+	for (ulint i = srv_undo_tablespaces_active; i--; ) {
 		trx_purge_mark_undo_for_truncate(&purge_sys->undo_trunc);
 		trx_purge_initiate_truncate(limit, &purge_sys->undo_trunc);
 	}
@@ -1638,22 +1627,6 @@ trx_purge_wait_for_workers_to_complete(
 	ut_a(srv_get_task_queue_length() == 0);
 }
 
-/******************************************************************//**
-Remove old historical changes from the rollback segments. */
-static
-void
-trx_purge_truncate(void)
-/*====================*/
-{
-	ut_ad(trx_purge_check_limit());
-
-	if (purge_sys->limit.trx_no == 0) {
-		trx_purge_truncate_history(&purge_sys->iter, &purge_sys->view);
-	} else {
-		trx_purge_truncate_history(&purge_sys->limit, &purge_sys->view);
-	}
-}
-
 /*******************************************************************//**
 This function runs a purge batch.
 @return number of undo log pages handled in the batch */
@@ -1742,7 +1715,11 @@ trx_purge(
 #endif /* UNIV_DEBUG */
 
 	if (truncate) {
-		trx_purge_truncate();
+		trx_purge_truncate_history(
+			purge_sys->limit.trx_no
+			? &purge_sys->limit
+			: &purge_sys->iter,
+			&purge_sys->view);
 	}
 
 	MONITOR_INC_VALUE(MONITOR_PURGE_INVOKED, 1);

storage/innobase/trx/trx0sys.cc

@@ -935,8 +935,14 @@ trx_sys_create_rsegs()
 
 	ut_ad(srv_undo_logs <= srv_available_undo_logs);
 
-	ib::info() << srv_undo_logs << " out of " << srv_available_undo_logs
-		<< " rollback segments are active.";
+	ib::info info;
+	info << srv_undo_logs << " out of " << srv_available_undo_logs;
+	if (srv_undo_tablespaces_active) {
+		info << " rollback segments in " << srv_undo_tablespaces_active
+		<< " undo tablespaces are active.";
+	} else {
+		info << " rollback segments are active.";
+	}
 
 	return(true);
 }