diff --git a/libmariadb b/libmariadb
index e9868bfce0d30..d1387356292fb 160000
--- a/libmariadb
+++ b/libmariadb
@@ -1 +1 @@
-Subproject commit e9868bfce0d30e789d89272f190c1fcb64f78904
+Subproject commit d1387356292fb840c7736aeb8f449310c3139087
diff --git a/mysql-test/r/check_constraint.result b/mysql-test/r/check_constraint.result
index 1743bb9704716..7447550ed0937 100644
--- a/mysql-test/r/check_constraint.result
+++ b/mysql-test/r/check_constraint.result
@@ -140,3 +140,7 @@ create table t1 (a int, b int, check(a>0));
 alter table t1 drop column a;
 ERROR 42S22: Unknown column 'a' in 'CHECK'
 drop table t1;
+create table t1 (a int check (@b in (select user from mysql.user)));
+ERROR HY000: Function or expression 'select ...' cannot be used in the CHECK clause of `a`
+create table t1 (a int check (a > @b));
+ERROR HY000: Function or expression '@b' cannot be used in the CHECK clause of `a`
diff --git a/mysql-test/suite/innodb/r/log_file.result b/mysql-test/suite/innodb/r/log_file.result
index 352e4b76cf1f1..918faec8adae5 100644
--- a/mysql-test/suite/innodb/r/log_file.result
+++ b/mysql-test/suite/innodb/r/log_file.result
@@ -207,7 +207,7 @@ SELECT * FROM INFORMATION_SCHEMA.ENGINES
 WHERE engine = 'innodb'
 AND support IN ('YES', 'DEFAULT', 'ENABLED');
 ENGINE	SUPPORT	COMMENT	TRANSACTIONS	XA	SAVEPOINTS
-FOUND /Expected to open 3 undo tablespaces but was able to find only 1 undo tablespaces/ in mysqld.1.err
+FOUND /InnoDB: Unable to open undo tablespace.*undo002/ in mysqld.1.err
 bak_ib_logfile0
 bak_ib_logfile1
 bak_ib_logfile2
@@ -244,7 +244,7 @@ SELECT * FROM INFORMATION_SCHEMA.ENGINES
 WHERE engine = 'innodb'
 AND support IN ('YES', 'DEFAULT', 'ENABLED');
 ENGINE	SUPPORT	COMMENT	TRANSACTIONS	XA	SAVEPOINTS
-FOUND /Expected to open 3 undo tablespaces but was able to find only 0 undo tablespaces/ in mysqld.1.err
+FOUND /InnoDB: Unable to open undo tablespace.*undo001/ in mysqld.1.err
 bak_ib_logfile0
 bak_ib_logfile1
 bak_ib_logfile2
diff --git a/mysql-test/suite/innodb/t/log_file.test b/mysql-test/suite/innodb/t/log_file.test
index c50257a69bed8..e0f4b85c6825b 100644
--- a/mysql-test/suite/innodb/t/log_file.test
+++ b/mysql-test/suite/innodb/t/log_file.test
@@ -41,7 +41,7 @@ AND support IN ('YES', 'DEFAULT', 'ENABLED');
 --let $ibp=$ibp --innodb-data-file-path=ibdata1:16M;ibdata2:10M:autoextend
 
 --echo # Start mysqld without the possibility to create innodb_undo_tablespaces
---let $restart_parameters= $ibp --innodb-undo-tablespaces=3
+--let $restart_parameters= $ibp
 --mkdir $bugdir/undo002
 --source include/restart_mysqld.inc
 eval $check_no_innodb;
@@ -172,7 +172,7 @@ let SEARCH_PATTERN=undo tablespace .*undo003.* exists\. Creating system tablespa
 --source include/start_mysqld.inc
 eval $check_no_innodb;
 --source include/shutdown_mysqld.inc
-let SEARCH_PATTERN=Expected to open 3 undo tablespaces but was able to find only 1 undo tablespaces;
+let SEARCH_PATTERN=InnoDB: Unable to open undo tablespace.*undo002;
 --source include/search_pattern_in_file.inc
 # clean up & Restore
 --source ../include/log_file_cleanup.inc
@@ -184,7 +184,7 @@ let SEARCH_PATTERN=Expected to open 3 undo tablespaces but was able to find only
 --source include/start_mysqld.inc
 eval $check_no_innodb;
 --source include/shutdown_mysqld.inc
-let SEARCH_PATTERN=Expected to open 3 undo tablespaces but was able to find only 0 undo tablespaces;
+let SEARCH_PATTERN=InnoDB: Unable to open undo tablespace.*undo001;
 --source include/search_pattern_in_file.inc
 
 # clean up & Restore
diff --git a/mysql-test/suite/innodb_zip/disabled.def b/mysql-test/suite/innodb_zip/disabled.def
index 294204f409c4f..8b137891791fe 100644
--- a/mysql-test/suite/innodb_zip/disabled.def
+++ b/mysql-test/suite/innodb_zip/disabled.def
@@ -1 +1 @@
-cmp_per_index:  MDEV-11629
+
diff --git a/mysql-test/suite/innodb_zip/r/cmp_per_index.result b/mysql-test/suite/innodb_zip/r/cmp_per_index.result
index 5b899e9ff7105..b380071c623aa 100644
--- a/mysql-test/suite/innodb_zip/r/cmp_per_index.result
+++ b/mysql-test/suite/innodb_zip/r/cmp_per_index.result
@@ -39,13 +39,13 @@ BEGIN;
 COMMIT;
 ALTER TABLE t DROP INDEX c;
 GRANT USAGE ON *.* TO 'tuser01'@'localhost' IDENTIFIED BY 'cDJvI9s_Uq';
-Warnings:
-Level	Warning
-Code	1287
-Message	Using GRANT for creating new user is deprecated and will be removed in future release. Create new user with CREATE USER statement.
 FLUSH PRIVILEGES;
+connect  con1,localhost,tuser01,cDJvI9s_Uq,;
+connection con1;
 SELECT * FROM information_schema.innodb_cmp_per_index;
 ERROR 42000: Access denied; you need (at least one of) the PROCESS privilege(s) for this operation
+connection default;
+disconnect con1;
 DROP USER 'tuser01'@'localhost';
 SELECT
 database_name,
@@ -70,7 +70,6 @@ index_name	PRIMARY
 compress_ops	65
 compress_ops_ok	65
 uncompress_ops	0
-# restart
 SET GLOBAL innodb_cmp_per_index_enabled=ON;
 SELECT COUNT(*) FROM t;
 COUNT(*)	128
@@ -86,9 +85,15 @@ FROM information_schema.innodb_cmp_per_index
 ORDER BY 1, 2, 3;
 database_name	test
 table_name	t
+index_name	b
+compress_ops	0
+compress_ops_ok	0
+uncompress_ops	6
+database_name	test
+table_name	t
 index_name	PRIMARY
 compress_ops	0
 compress_ops_ok	0
-uncompress_ops	9
+uncompress_ops	5
 DROP TABLE t;
 SET GLOBAL innodb_cmp_per_index_enabled=default;
diff --git a/mysql-test/suite/innodb_zip/t/cmp_per_index.opt b/mysql-test/suite/innodb_zip/t/cmp_per_index.opt
new file mode 100644
index 0000000000000..a031a64fc6ca8
--- /dev/null
+++ b/mysql-test/suite/innodb_zip/t/cmp_per_index.opt
@@ -0,0 +1,2 @@
+--innodb_log_compressed_pages=on
+--innodb_cmp_per_index_reset
diff --git a/mysql-test/suite/vcol/r/wrong_arena.result b/mysql-test/suite/vcol/r/wrong_arena.result
index 8a07c828288bf..e86026852e4b1 100644
--- a/mysql-test/suite/vcol/r/wrong_arena.result
+++ b/mysql-test/suite/vcol/r/wrong_arena.result
@@ -40,12 +40,6 @@ connection default;
 select * from t1;
 a	b	c	d	e
 2010-10-10 10:10:10	1	0	0	NULL
-Warnings:
-Warning	1292	Incorrect datetime value: '1'
-Warning	1292	Incorrect datetime value: '2'
-Warning	1292	Incorrect datetime value: '1'
-Warning	1292	Incorrect datetime value: '1'
-Warning	1292	Incorrect datetime value: '2'
 drop table t1;
 connect con1, localhost, root;
 create table t1 (a datetime,
diff --git a/mysql-test/suite/vcol/t/wrong_arena.test b/mysql-test/suite/vcol/t/wrong_arena.test
index 484f1fe685df6..340634422ae65 100644
--- a/mysql-test/suite/vcol/t/wrong_arena.test
+++ b/mysql-test/suite/vcol/t/wrong_arena.test
@@ -16,11 +16,15 @@ create table t1 (a datetime,
 );
 show create table t1;
 connect con1, localhost, root;
+disable_warnings;
 insert t1 (a) values ('2010-10-10 10:10:10');
+enable_warnings;
 select * from t1;
 disconnect con1;
 connection default;
+disable_warnings;
 select * from t1;
+enable_warnings;
 drop table t1;
 
 connect con1, localhost, root;
diff --git a/mysql-test/t/check_constraint.test b/mysql-test/t/check_constraint.test
index 7c5d30b6cd328..437463ee45736 100644
--- a/mysql-test/t/check_constraint.test
+++ b/mysql-test/t/check_constraint.test
@@ -86,3 +86,11 @@ create table t1 (a int, b int, check(a>0));
 --error ER_BAD_FIELD_ERROR
 alter table t1 drop column a;
 drop table t1;
+
+#
+# MDEV-12421 Check constraint with query crashes server and renders DB unusable
+#
+--error ER_GENERATED_COLUMN_FUNCTION_IS_NOT_ALLOWED
+create table t1 (a int check (@b in (select user from mysql.user)));
+--error ER_GENERATED_COLUMN_FUNCTION_IS_NOT_ALLOWED
+create table t1 (a int check (a > @b));
diff --git a/mysql-test/t/mdev-504.test b/mysql-test/t/mdev-504.test
index 76232927cd98d..551c21c37d015 100644
--- a/mysql-test/t/mdev-504.test
+++ b/mysql-test/t/mdev-504.test
@@ -1,5 +1,5 @@
 --source include/not_valgrind.inc
---disable_ps_protocol
+--source include/no_protocol.inc
 
 SET GLOBAL net_write_timeout = 900; 
 
diff --git a/plugin/aws_key_management/CMakeLists.txt b/plugin/aws_key_management/CMakeLists.txt
index 9e012b646966c..d83c483018333 100644
--- a/plugin/aws_key_management/CMakeLists.txt
+++ b/plugin/aws_key_management/CMakeLists.txt
@@ -137,8 +137,8 @@ ELSE()
   INCLUDE_DIRECTORIES(${CMAKE_BINARY_DIR}/aws_sdk_cpp/include)
 ENDIF()
 
-MYSQL_ADD_PLUGIN(aws_key_management aws_key_management_plugin.cc 
-                 COMPONENT aws-key-management)
 ADD_DEFINITIONS(${SSL_DEFINES}) # Need to know whether openssl should be initialized
 SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}  ${CXX11_FLAGS}")
-TARGET_LINK_LIBRARIES(aws_key_management ${AWS_SDK_LIBS})
+MYSQL_ADD_PLUGIN(aws_key_management aws_key_management_plugin.cc
+                 LINK_LIBRARIES ${AWS_SDK_LIBS}
+                 COMPONENT aws-key-management)
diff --git a/sql/sql_show.cc b/sql/sql_show.cc
index 18bc19bb85eff..6564504eff471 100644
--- a/sql/sql_show.cc
+++ b/sql/sql_show.cc
@@ -4667,7 +4667,7 @@ static int fill_schema_table_from_frm(THD *thd, TABLE *table,
     table_list.view= (LEX*) share->is_view;
     res= schema_table->process_table(thd, &table_list, table,
                                      res, db_name, table_name);
-    free_root(&tbl.mem_root, MYF(0));
+    closefrm(&tbl);
   }
 
 
diff --git a/sql/sql_yacc.yy b/sql/sql_yacc.yy
index 595218023eb06..e030ecde0864d 100644
--- a/sql/sql_yacc.yy
+++ b/sql/sql_yacc.yy
@@ -5985,8 +5985,8 @@ field_list_item:
         ;
 
 column_def:
-          field_spec opt_check_constraint
-          { $$= $1;  $$->check_constraint= $2; }
+          field_spec
+          { $$= $1; }
         | field_spec references
           { $$= $1; }
         ;
@@ -6124,11 +6124,13 @@ field_spec:
             lex->init_last_field(f, $1.str, NULL);
             $<create_field>$= f;
           }
-          field_type_or_serial
+          field_type_or_serial opt_check_constraint
           {
             LEX *lex=Lex;
             $$= $<create_field>2;
 
+            $$->check_constraint= $4;
+
             if ($$->check(thd))
               MYSQL_YYABORT;
 
diff --git a/storage/innobase/handler/ha_innodb.cc b/storage/innobase/handler/ha_innodb.cc
index 3dc22fe58d857..6aacdd48ad853 100644
--- a/storage/innobase/handler/ha_innodb.cc
+++ b/storage/innobase/handler/ha_innodb.cc
@@ -22140,7 +22140,7 @@ innobase_undo_logs_init_default_max()
 {
 	MYSQL_SYSVAR_NAME(undo_logs).max_val
 		= MYSQL_SYSVAR_NAME(undo_logs).def_val
-		= static_cast<unsigned long>(srv_available_undo_logs);
+		= srv_available_undo_logs;
 }
 
 /****************************************************************************
diff --git a/storage/innobase/include/srv0srv.h b/storage/innobase/include/srv0srv.h
index e469cd90737e0..eb08c47896522 100644
--- a/storage/innobase/include/srv0srv.h
+++ b/storage/innobase/include/srv0srv.h
@@ -334,9 +334,6 @@ extern my_bool	srv_undo_log_truncate;
 /* Enables or disables this prefix optimization.  Disabled by default. */
 extern my_bool	srv_prefix_index_cluster_optimization;
 
-/** UNDO logs not redo logged, these logs reside in the temp tablespace.*/
-extern const ulong	srv_tmp_undo_logs;
-
 /** Default size of UNDO tablespace while it is created new. */
 extern const ulint	SRV_UNDO_TABLESPACE_SIZE_IN_PAGES;
 
@@ -518,7 +515,8 @@ extern uint	srv_spin_wait_delay;
 extern ibool	srv_priority_boost;
 
 extern ulint	srv_truncated_status_writes;
-extern ulint	srv_available_undo_logs;
+/** Number of initialized rollback segments for persistent undo log */
+extern ulong	srv_available_undo_logs;
 
 #if defined UNIV_DEBUG || defined UNIV_IBUF_DEBUG
 extern my_bool	srv_ibuf_disable_background_merge;
diff --git a/storage/innobase/include/trx0rseg.h b/storage/innobase/include/trx0rseg.h
index e17d11b383e75..95774cbf476e6 100644
--- a/storage/innobase/include/trx0rseg.h
+++ b/storage/innobase/include/trx0rseg.h
@@ -85,16 +85,6 @@ trx_rsegf_undo_find_free(
 /*=====================*/
 	trx_rsegf_t*	rsegf,	/*!< in: rollback segment header */
 	mtr_t*		mtr);	/*!< in: mtr */
-/** Get a rollback segment.
-@param[in]	id	rollback segment id
-@return rollback segment */
-UNIV_INLINE
-trx_rseg_t*
-trx_rseg_get_on_id(ulint id)
-{
-	ut_a(id < TRX_SYS_N_RSEGS);
-	return(trx_sys->rseg_array[id]);
-}
 
 /** Creates a rollback segment header.
 This function is called only when a new rollback segment is created in
@@ -119,14 +109,14 @@ trx_rseg_array_init();
 void
 trx_rseg_mem_free(trx_rseg_t* rseg);
 
-/*********************************************************************
-Creates a rollback segment. */
+/** Create a persistent rollback segment.
+@param[in]	space_id	system or undo tablespace id */
 trx_rseg_t*
-trx_rseg_create(
-/*============*/
-	ulint	space_id,	/*!< in: id of UNDO tablespace */
-	ulint   nth_free_slot);	/*!< in: allocate nth free slot.
-				0 means next free slots. */
+trx_rseg_create(ulint space_id);
+
+/** Create the temporary rollback segments. */
+void
+trx_temp_rseg_create();
 
 /********************************************************************
 Get the number of unique rollback tablespaces in use except space id 0.
@@ -205,6 +195,14 @@ struct trx_rseg_t {
 	/** If true, then skip allocating this rseg as it reside in
 	UNDO-tablespace marked for truncate. */
 	bool				skip_allocation;
+
+	/** @return whether the rollback segment is persistent */
+	bool is_persistent() const
+	{
+		ut_ad(space == SRV_TMP_SPACE_ID
+		      || space <= srv_undo_tablespaces);
+		return(space != SRV_TMP_SPACE_ID);
+	}
 };
 
 /* Undo log segment slot in a rollback segment header */
diff --git a/storage/innobase/include/trx0sys.h b/storage/innobase/include/trx0sys.h
index 8ebb74e3d86f8..b867600653d8c 100644
--- a/storage/innobase/include/trx0sys.h
+++ b/storage/innobase/include/trx0sys.h
@@ -75,17 +75,10 @@ Creates and initializes the transaction system at the database creation. */
 void
 trx_sys_create_sys_pages(void);
 /*==========================*/
-/****************************************************************//**
-Looks for a free slot for a rollback segment in the trx system file copy.
-@return slot index or ULINT_UNDEFINED if not found */
+/** @return an unallocated rollback segment slot in the TRX_SYS header
+@retval ULINT_UNDEFINED if not found */
 ulint
-trx_sysf_rseg_find_free(
-/*====================*/
-	mtr_t*	mtr,			/*!< in/out: mtr */
-	bool	include_tmp_slots,	/*!< in: if true, report slots reserved
-					for temp-tablespace as free slots. */
-	ulint	nth_free_slots);	/*!< in: allocate nth free slot.
-					0 means next free slot. */
+trx_sysf_rseg_find_free(mtr_t* mtr);
 /**********************************************************************//**
 Gets a pointer to the transaction system file copy and x-locks its page.
 @return pointer to system file copy, page x-locked */
@@ -160,14 +153,6 @@ trx_sys_get_max_trx_id(void);
 extern uint			trx_rseg_n_slots_debug;
 #endif
 
-/*****************************************************************//**
-Check if slot-id is reserved slot-id for noredo rsegs. */
-UNIV_INLINE
-bool
-trx_sys_is_noredo_rseg_slot(
-/*========================*/
-	ulint	slot_id);	/*!< in: slot_id to check */
-
 /*****************************************************************//**
 Writes a trx id to an index page. In case that the id size changes in
 some future version, this function should be used instead of
@@ -319,16 +304,10 @@ trx_sys_file_format_max_set(
 	ulint		format_id,	/*!< in: file format id */
 	const char**	name);		/*!< out: max file format name or
 					NULL if not needed. */
-/*********************************************************************
-Creates the rollback segments
-@return number of rollback segments that are active. */
-ulint
-trx_sys_create_rsegs(
-/*=================*/
-	ulint	n_spaces,	/*!< number of tablespaces for UNDO logs */
-	ulint	n_rsegs,	/*!< number of rollback segments to create */
-	ulint	n_tmp_rsegs);	/*!< number of rollback segments reserved for
-				temp-tables. */
+/** Create the rollback segments.
+@return	whether the creation succeeded */
+bool
+trx_sys_create_rsegs();
 /*****************************************************************//**
 Get the number of transaction in the system, independent of their state.
 @return count of transactions in trx_sys_t::trx_list */
@@ -556,13 +535,15 @@ struct trx_sys_t {
 					transactions which exist or existed */
 #endif /* UNIV_DEBUG */
 
-	char		pad1[64];	/*!< To avoid false sharing */
+	/** Avoid false sharing */
+	const char	pad1[CACHE_LINE_SIZE];
 	trx_ut_list_t	rw_trx_list;	/*!< List of active and committed in
 					memory read-write transactions, sorted
 					on trx id, biggest first. Recovered
 					transactions are always on this list. */
 
-	char		pad2[64];	/*!< To avoid false sharing */
+	/** Avoid false sharing */
+	const char	pad2[CACHE_LINE_SIZE];
 	trx_ut_list_t	mysql_trx_list;	/*!< List of transactions created
 					for MySQL. All user transactions are
 					on mysql_trx_list. The rw_trx_list
@@ -582,7 +563,13 @@ struct trx_sys_t {
 					to ensure right order of removal and
 					consistent snapshot. */
 
-	char		pad3[64];	/*!< To avoid false sharing */
+	/** Avoid false sharing */
+	const char	pad3[CACHE_LINE_SIZE];
+	/** Temporary rollback segments */
+	trx_rseg_t*	temp_rsegs[TRX_SYS_N_RSEGS];
+	/** Avoid false sharing */
+	const char	pad4[CACHE_LINE_SIZE];
+
 	trx_rseg_t*	rseg_array[TRX_SYS_N_RSEGS];
 					/*!< Pointer array to rollback
 					segments; NULL if slot not in use;
diff --git a/storage/innobase/include/trx0sys.ic b/storage/innobase/include/trx0sys.ic
index f03535c53b311..1c805ead4b31d 100644
--- a/storage/innobase/include/trx0sys.ic
+++ b/storage/innobase/include/trx0sys.ic
@@ -191,18 +191,6 @@ trx_write_trx_id(
 	mach_write_to_6(ptr, id);
 }
 
-/*****************************************************************//**
-Check if slot-id is reserved slot-id for noredo rsegs. */
-UNIV_INLINE
-bool
-trx_sys_is_noredo_rseg_slot(
-/*========================*/
-	ulint	slot_id)	/*!< in: slot_id to check */
-{
-	/* Slots allocated from temp-tablespace are no-redo slots. */
-	return(slot_id > 0 && slot_id < (srv_tmp_undo_logs + 1));
-}
-
 /*****************************************************************//**
 Reads a trx id from an index page. In case that the id size changes in
 some future version, this function should be used instead of
diff --git a/storage/innobase/include/trx0trx.h b/storage/innobase/include/trx0trx.h
index 7da3bfb5459d4..d0a67a7ed284b 100644
--- a/storage/innobase/include/trx0trx.h
+++ b/storage/innobase/include/trx0trx.h
@@ -507,14 +507,6 @@ trx_id_t
 trx_get_id_for_print(
 	const trx_t*	trx);
 
-/****************************************************************//**
-Assign a transaction temp-tablespace bound rollback-segment. */
-void
-trx_assign_rseg(
-/*============*/
-	trx_t*		trx);		/*!< transaction that involves write
-					to temp-table. */
-
 /** Create the trx_t pool */
 void
 trx_pool_init();
@@ -869,12 +861,6 @@ struct trx_rsegs_t {
 	trx_temp_undo_t	m_noredo;
 };
 
-enum trx_rseg_type_t {
-	TRX_RSEG_TYPE_NONE = 0,		/*!< void rollback segment type. */
-	TRX_RSEG_TYPE_REDO,		/*!< redo rollback segment. */
-	TRX_RSEG_TYPE_NOREDO		/*!< non-redo rollback segment. */
-};
-
 struct TrxVersion {
 	TrxVersion(trx_t* trx);
 
@@ -1295,6 +1281,22 @@ struct trx_t {
 	{
 		return(has_logged_persistent() || rsegs.m_noredo.undo);
 	}
+
+	/** @return rollback segment for modifying temporary tables */
+	trx_rseg_t* get_temp_rseg()
+	{
+		if (trx_rseg_t* rseg = rsegs.m_noredo.rseg) {
+			ut_ad(id != 0);
+			return(rseg);
+		}
+
+		return(assign_temp_rseg());
+	}
+
+private:
+	/** Assign a rollback segment for modifying temporary tables.
+	@return the assigned rollback segment */
+	trx_rseg_t* assign_temp_rseg();
 };
 
 /**
diff --git a/storage/innobase/row/row0purge.cc b/storage/innobase/row/row0purge.cc
index ce9a265bd8c12..2a13203b74764 100644
--- a/storage/innobase/row/row0purge.cc
+++ b/storage/innobase/row/row0purge.cc
@@ -741,10 +741,11 @@ row_purge_upd_exist_or_extern_func(
 						 &is_insert, &rseg_id,
 						 &page_no, &offset);
 
-			rseg = trx_rseg_get_on_id(rseg_id);
+			rseg = trx_sys->rseg_array[rseg_id];
 
 			ut_a(rseg != NULL);
-			ut_a(rseg->id == rseg_id);
+			ut_ad(rseg->id == rseg_id);
+			ut_ad(rseg->is_persistent());
 
 			mtr_start(&mtr);
 
diff --git a/storage/innobase/srv/srv0srv.cc b/storage/innobase/srv/srv0srv.cc
index b689cd012c6a6..a05bb5300a34b 100644
--- a/storage/innobase/srv/srv0srv.cc
+++ b/storage/innobase/srv/srv0srv.cc
@@ -139,10 +139,6 @@ my_bool	srv_undo_log_truncate = FALSE;
 /** Maximum size of undo tablespace. */
 unsigned long long	srv_max_undo_log_size;
 
-/** UNDO logs that are not redo logged.
-These logs reside in the temp tablespace.*/
-const ulong		srv_tmp_undo_logs = 32;
-
 /** Default undo tablespace size in UNIV_PAGEs count (10MB). */
 const ulint SRV_UNDO_TABLESPACE_SIZE_IN_PAGES =
 	((1024 * 1024) * 10) / UNIV_PAGE_SIZE_DEF;
@@ -403,37 +399,38 @@ UNIV_INTERN ulong	srv_n_spin_wait_rounds	= 15;
 uint	srv_spin_wait_delay;
 ibool	srv_priority_boost	= TRUE;
 
-static ulint		srv_n_rows_inserted_old		= 0;
-static ulint		srv_n_rows_updated_old		= 0;
-static ulint		srv_n_rows_deleted_old		= 0;
-static ulint		srv_n_rows_read_old		= 0;
-static ulint		srv_n_system_rows_inserted_old	= 0;
-static ulint		srv_n_system_rows_updated_old	= 0;
-static ulint		srv_n_system_rows_deleted_old	= 0;
-static ulint		srv_n_system_rows_read_old	= 0;
-
-ulint	srv_truncated_status_writes	= 0;
-ulint	srv_available_undo_logs         = 0;
-
-UNIV_INTERN ib_uint64_t srv_page_compression_saved      = 0;
-UNIV_INTERN ib_uint64_t srv_page_compression_trim_sect512       = 0;
-UNIV_INTERN ib_uint64_t srv_page_compression_trim_sect4096      = 0;
-UNIV_INTERN ib_uint64_t srv_index_pages_written         = 0;
-UNIV_INTERN ib_uint64_t srv_non_index_pages_written     = 0;
-UNIV_INTERN ib_uint64_t srv_pages_page_compressed       = 0;
-UNIV_INTERN ib_uint64_t srv_page_compressed_trim_op     = 0;
-UNIV_INTERN ib_uint64_t srv_page_compressed_trim_op_saved     = 0;
-UNIV_INTERN ib_uint64_t srv_index_page_decompressed     = 0;
+static ulint		srv_n_rows_inserted_old;
+static ulint		srv_n_rows_updated_old;
+static ulint		srv_n_rows_deleted_old;
+static ulint		srv_n_rows_read_old;
+static ulint		srv_n_system_rows_inserted_old;
+static ulint		srv_n_system_rows_updated_old;
+static ulint		srv_n_system_rows_deleted_old;
+static ulint		srv_n_system_rows_read_old;
+
+ulint	srv_truncated_status_writes;
+/** Number of initialized rollback segments for persistent undo log */
+ulong	srv_available_undo_logs;
+
+UNIV_INTERN ib_uint64_t srv_page_compression_saved;
+UNIV_INTERN ib_uint64_t srv_page_compression_trim_sect512;
+UNIV_INTERN ib_uint64_t srv_page_compression_trim_sect4096;
+UNIV_INTERN ib_uint64_t srv_index_pages_written;
+UNIV_INTERN ib_uint64_t srv_non_index_pages_written;
+UNIV_INTERN ib_uint64_t srv_pages_page_compressed;
+UNIV_INTERN ib_uint64_t srv_page_compressed_trim_op;
+UNIV_INTERN ib_uint64_t srv_page_compressed_trim_op_saved;
+UNIV_INTERN ib_uint64_t srv_index_page_decompressed;
 
 /* Defragmentation */
-UNIV_INTERN my_bool	srv_defragment = FALSE;
+UNIV_INTERN my_bool	srv_defragment;
 UNIV_INTERN uint	srv_defragment_n_pages = 7;
-UNIV_INTERN uint	srv_defragment_stats_accuracy = 0;
+UNIV_INTERN uint	srv_defragment_stats_accuracy;
 UNIV_INTERN uint	srv_defragment_fill_factor_n_recs = 20;
 UNIV_INTERN double	srv_defragment_fill_factor = 0.9;
 UNIV_INTERN uint	srv_defragment_frequency =
 	SRV_DEFRAGMENT_FREQUENCY_DEFAULT;
-UNIV_INTERN ulonglong	srv_defragment_interval = 0;
+UNIV_INTERN ulonglong	srv_defragment_interval;
 
 /* Set the following to 0 if you want InnoDB to write messages on
 stderr on startup/shutdown. */
diff --git a/storage/innobase/srv/srv0start.cc b/storage/innobase/srv/srv0start.cc
index 7c16ce1e58f4f..bcb52fc5bfb57 100644
--- a/storage/innobase/srv/srv0start.cc
+++ b/storage/innobase/srv/srv0start.cc
@@ -804,20 +804,12 @@ srv_check_undo_redo_logs_exists()
 
 undo::undo_spaces_t	undo::Truncate::s_fix_up_spaces;
 
-/********************************************************************
-Opens the configured number of undo tablespaces.
+/** Open the configured number of dedicated undo tablespaces.
+@param[in]	create_new_db	whether the database is being initialized
 @return DB_SUCCESS or error code */
 static
 dberr_t
-srv_undo_tablespaces_init(
-/*======================*/
-	bool		create_new_db,		/*!< in: TRUE if new db being
-						created */
-	const ulint	n_conf_tablespaces,	/*!< in: configured undo
-						tablespaces */
-	ulint*		n_opened)		/*!< out: number of UNDO
-						tablespaces successfully
-						discovered and opened */
+srv_undo_tablespaces_init(bool create_new_db)
 {
 	ulint			i;
 	dberr_t			err = DB_SUCCESS;
@@ -825,9 +817,9 @@ srv_undo_tablespaces_init(
 	ulint			n_undo_tablespaces;
 	ulint			undo_tablespace_ids[TRX_SYS_N_RSEGS + 1];
 
-	*n_opened = 0;
+	srv_undo_tablespaces_open = 0;
 
-	ut_a(n_conf_tablespaces <= TRX_SYS_N_RSEGS);
+	ut_a(srv_undo_tablespaces <= TRX_SYS_N_RSEGS);
 
 	memset(undo_tablespace_ids, 0x0, sizeof(undo_tablespace_ids));
 
@@ -839,7 +831,7 @@ srv_undo_tablespaces_init(
 	the location of the undo tablespaces and their space ids this
 	restriction will/should be lifted. */
 
-	for (i = 0; create_new_db && i < n_conf_tablespaces; ++i) {
+	for (i = 0; create_new_db && i < srv_undo_tablespaces; ++i) {
 		char	name[OS_FILE_MAX_PATH];
 
 		ut_snprintf(
@@ -902,7 +894,7 @@ srv_undo_tablespaces_init(
 			}
 		}
 	} else {
-		n_undo_tablespaces = n_conf_tablespaces;
+		n_undo_tablespaces = srv_undo_tablespaces;
 
 		for (i = 1; i <= n_undo_tablespaces; ++i) {
 			undo_tablespace_ids[i - 1] = i;
@@ -944,7 +936,7 @@ srv_undo_tablespaces_init(
 
 		prev_space_id = undo_tablespace_ids[i];
 
-		++*n_opened;
+		++srv_undo_tablespaces_open;
 	}
 
 	/* Open any extra unused undo tablespaces. These must be contiguous.
@@ -968,19 +960,17 @@ srv_undo_tablespaces_init(
 
 		++n_undo_tablespaces;
 
-		++*n_opened;
+		++srv_undo_tablespaces_open;
 	}
 
 	/* If the user says that there are fewer than what we find we
 	tolerate that discrepancy but not the inverse. Because there could
 	be unused undo tablespaces for future use. */
 
-	if (n_conf_tablespaces > n_undo_tablespaces) {
-		ib::error() << "Expected to open " << n_conf_tablespaces
-			<< " undo tablespaces but was able to find only "
-			<< n_undo_tablespaces << " undo tablespaces. Set the"
-			" innodb_undo_tablespaces parameter to the correct"
-			" value and retry. Suggested value is "
+	if (srv_undo_tablespaces > n_undo_tablespaces) {
+		ib::error() << "Expected to open innodb_undo_tablespaces="
+			<< srv_undo_tablespaces
+			<< " but was able to find only "
 			<< n_undo_tablespaces;
 
 		return(err != DB_SUCCESS ? err : DB_ERROR);
@@ -988,15 +978,13 @@ srv_undo_tablespaces_init(
 	} else  if (n_undo_tablespaces > 0) {
 
 		ib::info() << "Opened " << n_undo_tablespaces
-			<< " undo tablespaces";
-
-		ib::info() << srv_undo_tablespaces_active << " undo tablespaces"
-			<< " made active";
+			<< " undo tablespaces ("
+			<< srv_undo_tablespaces_active
+			<< " active)";
 
-		if (n_conf_tablespaces == 0) {
-			ib::warn() << "Will use system tablespace for all newly"
-				<< " created rollback-segment as"
-				<< " innodb_undo_tablespaces=0";
+		if (srv_undo_tablespaces == 0) {
+			ib::warn() << "innodb_undo_tablespaces=0 disables"
+				" dedicated undo log tablespaces";
 		}
 	}
 
@@ -2087,10 +2075,7 @@ innobase_start_or_create_for_mysql(void)
 	fil_open_log_and_system_tablespace_files();
 	ut_d(fil_space_get(0)->recv_size = srv_sys_space_size_debug);
 
-	err = srv_undo_tablespaces_init(
-		create_new_db,
-		srv_undo_tablespaces,
-		&srv_undo_tablespaces_open);
+	err = srv_undo_tablespaces_init(create_new_db);
 
 	/* If the force recovery is set very high then we carry on regardless
 	of all errors. Basically this is fingers crossed mode. */
@@ -2512,22 +2497,7 @@ innobase_start_or_create_for_mysql(void)
 	ut_a(srv_undo_logs > 0);
 	ut_a(srv_undo_logs <= TRX_SYS_N_RSEGS);
 
-	/* The number of rsegs that exist in InnoDB is given by status
-	variable srv_available_undo_logs. The number of rsegs to use can
-	be set using the dynamic global variable srv_undo_logs. */
-
-	srv_available_undo_logs = trx_sys_create_rsegs(
-		srv_undo_tablespaces, srv_undo_logs, srv_tmp_undo_logs);
-
-	if (srv_available_undo_logs == ULINT_UNDEFINED) {
-		/* Can only happen if server is read only. */
-		ut_a(srv_read_only_mode);
-		srv_undo_logs = ULONG_UNDEFINED;
-	} else if (srv_available_undo_logs < srv_undo_logs
-		   && !srv_force_recovery && !recv_needed_recovery) {
-		ib::error() << "System or UNDO tablespace is running of out"
-			    << " of space";
-		/* Should due to out of file space. */
+	if (!trx_sys_create_rsegs()) {
 		return(srv_init_abort(DB_ERROR));
 	}
 
diff --git a/storage/innobase/trx/trx0purge.cc b/storage/innobase/trx/trx0purge.cc
index 6ff4c882be8d9..f83d93778521b 100644
--- a/storage/innobase/trx/trx0purge.cc
+++ b/storage/innobase/trx/trx0purge.cc
@@ -327,17 +327,12 @@ trx_purge_remove_log_hdr(
 	my_atomic_addlint(&trx_sys->rseg_history_len, -1);
 }
 
-/** Frees an undo log segment which is in the history list. Removes the
-undo log hdr from the history list.
+/** Free an undo log segment, and remove the header from the history list.
 @param[in,out]	rseg		rollback segment
-@param[in]	hdr_addr	file address of log_hdr
-@param[in]	noredo		skip redo logging. */
+@param[in]	hdr_addr	file address of log_hdr */
 static
 void
-trx_purge_free_segment(
-	trx_rseg_t*	rseg,
-	fil_addr_t	hdr_addr,
-	bool		noredo)
+trx_purge_free_segment(trx_rseg_t* rseg, fil_addr_t hdr_addr)
 {
 	mtr_t		mtr;
 	trx_rsegf_t*	rseg_hdr;
@@ -345,16 +340,12 @@ trx_purge_free_segment(
 	trx_usegf_t*	seg_hdr;
 	ulint		seg_size;
 	ulint		hist_size;
-	bool		marked		= noredo;
+	bool		marked		= false;
 
 	for (;;) {
 		page_t*	undo_page;
 
 		mtr_start(&mtr);
-		if (noredo) {
-			mtr.set_log_mode(MTR_LOG_NO_REDO);
-		}
-		ut_ad(noredo == trx_sys_is_noredo_rseg_slot(rseg->id));
 
 		mutex_enter(&rseg->mutex);
 
@@ -428,14 +419,12 @@ trx_purge_free_segment(
 	mtr_commit(&mtr);
 }
 
-/********************************************************************//**
-Removes unnecessary history data from a rollback segment. */
+/** Remove unnecessary history data from a rollback segment.
+@param[in,out]	rseg		rollback segment
+@param[in]	limit		truncate offset */
 static
 void
-trx_purge_truncate_rseg_history(
-/*============================*/
-	trx_rseg_t*		rseg,		/*!< in: rollback segment */
-	const purge_iter_t*	limit)		/*!< in: truncate offset */
+trx_purge_truncate_rseg_history(trx_rseg_t* rseg, const purge_iter_t* limit)
 {
 	fil_addr_t	hdr_addr;
 	fil_addr_t	prev_hdr_addr;
@@ -445,13 +434,9 @@ trx_purge_truncate_rseg_history(
 	trx_usegf_t*	seg_hdr;
 	mtr_t		mtr;
 	trx_id_t	undo_trx_no;
-	const bool	noredo		= trx_sys_is_noredo_rseg_slot(
-		rseg->id);
 
 	mtr_start(&mtr);
-	if (noredo) {
-		mtr.set_log_mode(MTR_LOG_NO_REDO);
-	}
+	ut_ad(rseg->is_persistent());
 	mutex_enter(&(rseg->mutex));
 
 	rseg_hdr = trx_rsegf_get(rseg->space, rseg->page_no, &mtr);
@@ -509,7 +494,7 @@ trx_purge_truncate_rseg_history(
 
 		/* calls the trx_purge_remove_log_hdr()
 		inside trx_purge_free_segment(). */
-		trx_purge_free_segment(rseg, hdr_addr, noredo);
+		trx_purge_free_segment(rseg, hdr_addr);
 	} else {
 		/* Remove the log hdr from the rseg history. */
 		trx_purge_remove_log_hdr(rseg_hdr, log_hdr, &mtr);
@@ -519,9 +504,6 @@ trx_purge_truncate_rseg_history(
 	}
 
 	mtr_start(&mtr);
-	if (noredo) {
-		mtr.set_log_mode(MTR_LOG_NO_REDO);
-	}
 	mutex_enter(&(rseg->mutex));
 
 	rseg_hdr = trx_rsegf_get(rseg->space, rseg->page_no, &mtr);
@@ -806,10 +788,9 @@ trx_purge_mark_undo_for_truncate(
 	/* Step-2: Validation/Qualification checks
 	a. At-least 2 UNDO tablespaces so even if one UNDO tablespace
 	   is being truncated server can continue to operate.
-	b. At-least 2 UNDO redo rseg/undo logs (besides the default rseg-0)
+	b. At-least 2 persistent UNDO logs (besides the default rseg-0)
 	b. At-least 1 UNDO tablespace size > threshold. */
-	if (srv_undo_tablespaces_active < 2
-	    || (srv_undo_logs < (1 + srv_tmp_undo_logs + 2))) {
+	if (srv_undo_tablespaces_active < 2 || srv_undo_logs < 3) {
 		return;
 	}
 
@@ -846,11 +827,9 @@ trx_purge_mark_undo_for_truncate(
 	/* Step-3: Iterate over all the rsegs of selected UNDO tablespace
 	and mark them temporarily unavailable for allocation.*/
 	for (ulint i = 0; i < TRX_SYS_N_RSEGS; ++i) {
-		trx_rseg_t*	rseg = trx_sys->rseg_array[i];
-
-		if (rseg != NULL && !trx_sys_is_noredo_rseg_slot(rseg->id)) {
-			if (rseg->space
-				== undo_trunc->get_marked_space_id()) {
+		if (trx_rseg_t* rseg = trx_sys->rseg_array[i]) {
+			ut_ad(rseg->is_persistent());
+			if (rseg->space == undo_trunc->get_marked_space_id()) {
 
 				/* Once set this rseg will not be allocated
 				to new booting transaction but we will wait
diff --git a/storage/innobase/trx/trx0rec.cc b/storage/innobase/trx/trx0rec.cc
index 481e14d44dea6..47d24b631141b 100644
--- a/storage/innobase/trx/trx0rec.cc
+++ b/storage/innobase/trx/trx0rec.cc
@@ -1893,13 +1893,7 @@ trx_undo_report_row_operation(
 	if (is_temp) {
 		mtr.set_log_mode(MTR_LOG_NO_REDO);
 
-		rseg = trx->rsegs.m_noredo.rseg;
-
-		if (!rseg) {
-			trx_assign_rseg(trx);
-			rseg = trx->rsegs.m_noredo.rseg;
-		}
-
+		rseg = trx->get_temp_rseg();
 		pundo = &trx->rsegs.m_noredo.undo;
 	} else {
 		ut_ad(!trx->read_only);
@@ -2057,16 +2051,16 @@ trx_undo_report_row_operation(
 
 /*============== BUILDING PREVIOUS VERSION OF A RECORD ===============*/
 
-/******************************************************************//**
-Copies an undo record to heap. This function can be called if we know that
-the undo log record exists.
-@return own: copy of the record */
+/** Copy an undo record to heap.
+@param[in]	roll_ptr	roll pointer to a record that exists
+@param[in]	is_temp		whether this is a temporary table
+@param[in,out]	heap		memory heap where copied */
 static
 trx_undo_rec_t*
 trx_undo_get_undo_rec_low(
-/*======================*/
-	roll_ptr_t	roll_ptr,	/*!< in: roll pointer to record */
-	mem_heap_t*	heap)		/*!< in: memory heap where copied */
+	roll_ptr_t	roll_ptr,
+	bool		is_temp,
+	mem_heap_t*	heap)
 {
 	trx_undo_rec_t*	undo_rec;
 	ulint		rseg_id;
@@ -2079,7 +2073,10 @@ trx_undo_get_undo_rec_low(
 
 	trx_undo_decode_roll_ptr(roll_ptr, &is_insert, &rseg_id, &page_no,
 				 &offset);
-	rseg = trx_rseg_get_on_id(rseg_id);
+	rseg = is_temp
+		? trx_sys->temp_rsegs[rseg_id]
+		: trx_sys->rseg_array[rseg_id];
+	ut_ad(is_temp == !rseg->is_persistent());
 
 	mtr_start(&mtr);
 
@@ -2093,13 +2090,13 @@ trx_undo_get_undo_rec_low(
 	return(undo_rec);
 }
 
-/******************************************************************//**
-Copies an undo record to heap.
+/** Copy an undo record to heap.
 @param[in]	roll_ptr	roll pointer to record
+@param[in]	is_temp		whether this is a temporary table
+@param[in,out]	heap		memory heap where copied
 @param[in]	trx_id		id of the trx that generated
 				the roll pointer: it points to an
 				undo log of this transaction
-@param[in]	heap		memory heap where copied
 @param[in]	name		table name
 @param[out]	undo_rec	own: copy of the record
 @retval true if the undo log has been
@@ -2109,10 +2106,10 @@ NOTE: the caller must have latches on the clustered index page. */
 static MY_ATTRIBUTE((warn_unused_result))
 bool
 trx_undo_get_undo_rec(
-/*==================*/
 	roll_ptr_t		roll_ptr,
-	trx_id_t		trx_id,
+	bool			is_temp,
 	mem_heap_t*		heap,
+	trx_id_t		trx_id,
 	const table_name_t&	name,
 	trx_undo_rec_t**	undo_rec)
 {
@@ -2122,7 +2119,7 @@ trx_undo_get_undo_rec(
 
 	missing_history = purge_sys->view.changes_visible(trx_id, name);
 	if (!missing_history) {
-		*undo_rec = trx_undo_get_undo_rec_low(roll_ptr, heap);
+		*undo_rec = trx_undo_get_undo_rec_low(roll_ptr, is_temp, heap);
 	}
 
 	rw_lock_s_unlock(&purge_sys->latch);
@@ -2203,13 +2200,17 @@ trx_undo_prev_version_build(
 		return(true);
 	}
 
+	const bool is_temp = dict_table_is_temporary(index->table);
 	rec_trx_id = row_get_rec_trx_id(rec, index, offsets);
 
 	if (trx_undo_get_undo_rec(
-		roll_ptr, rec_trx_id, heap, index->table->name, &undo_rec)) {
+		    roll_ptr, is_temp, heap, rec_trx_id, index->table->name,
+		    &undo_rec)) {
 		if (v_status & TRX_UNDO_PREV_IN_PURGE) {
 			/* We are fetching the record being purged */
-			undo_rec = trx_undo_get_undo_rec_low(roll_ptr, heap);
+			ut_ad(!is_temp);
+			undo_rec = trx_undo_get_undo_rec_low(
+				roll_ptr, is_temp, heap);
 		} else {
 			/* The undo record may already have been purged,
 			during purge or semi-consistent read. */
diff --git a/storage/innobase/trx/trx0rseg.cc b/storage/innobase/trx/trx0rseg.cc
index 883e2eb60b2b5..3393a0464a856 100644
--- a/storage/innobase/trx/trx0rseg.cc
+++ b/storage/innobase/trx/trx0rseg.cc
@@ -90,12 +90,7 @@ trx_rseg_header_create(
 		trx_rsegf_set_nth_undo(rsegf, i, FIL_NULL, mtr);
 	}
 
-	if (!trx_sys_is_noredo_rseg_slot(rseg_slot_no)) {
-		/* Non-redo rseg are re-created on restart and so no need
-		to persist this information in sys-header. Anyway, on restart
-		this information is not valid too as there is no space with
-		persisted space-id on restart. */
-
+	if (space != SRV_TMP_SPACE_ID) {
 		/* Add the rollback segment info to the free slot in
 		the trx system header */
 
@@ -152,51 +147,48 @@ trx_rseg_mem_free(trx_rseg_t* rseg)
 	ut_free(rseg);
 }
 
-/** Creates and initializes a rollback segment object.
-The values for the fields are read from the header. The object is inserted to
-the rseg list of the trx system object and a pointer is inserted in the rseg
-array in the trx system object.
+/** Create a rollback segment object.
 @param[in]	id		rollback segment id
 @param[in]	space		space where the segment is placed
-@param[in]	page_no		page number of the segment header
-@param[in,out]	mtr		mini-transaction */
+@param[in]	page_no		page number of the segment header */
 static
-void
-trx_rseg_mem_create(
-	ulint			id,
-	ulint			space,
-	ulint			page_no,
-	mtr_t*			mtr)
+trx_rseg_t*
+trx_rseg_mem_create(ulint id, ulint space, ulint page_no)
 {
-	ulint		len;
-	trx_rseg_t*	rseg;
-	fil_addr_t	node_addr;
-	trx_rsegf_t*	rseg_header;
-	trx_ulogf_t*	undo_log_hdr;
-	ulint		sum_of_undo_sizes;
-
-	rseg = static_cast<trx_rseg_t*>(ut_zalloc_nokey(sizeof(trx_rseg_t)));
+	trx_rseg_t* rseg = static_cast<trx_rseg_t*>(
+		ut_zalloc_nokey(sizeof *rseg));
 
 	rseg->id = id;
 	rseg->space = space;
 	rseg->page_no = page_no;
-	rseg->trx_ref_count = 0;
-	rseg->skip_allocation = false;
+	rseg->last_page_no = FIL_NULL;
 
-	if (fsp_is_system_temporary(space)) {
-		mutex_create(LATCH_ID_NOREDO_RSEG, &rseg->mutex);
-	} else {
-		mutex_create(LATCH_ID_REDO_RSEG, &rseg->mutex);
-	}
+	mutex_create(rseg->is_persistent()
+		     ? LATCH_ID_REDO_RSEG : LATCH_ID_NOREDO_RSEG,
+		     &rseg->mutex);
 
 	UT_LIST_INIT(rseg->update_undo_list, &trx_undo_t::undo_list);
 	UT_LIST_INIT(rseg->update_undo_cached, &trx_undo_t::undo_list);
 	UT_LIST_INIT(rseg->insert_undo_list, &trx_undo_t::undo_list);
 	UT_LIST_INIT(rseg->insert_undo_cached, &trx_undo_t::undo_list);
 
-	trx_sys->rseg_array[id] = rseg;
+	return(rseg);
+}
+
+/** Restore the state of a persistent rollback segment.
+@param[in,out]	rseg	persistent rollback segment
+@param[in,out]	mtr	mini-transaction */
+static
+void
+trx_rseg_mem_restore(trx_rseg_t* rseg, mtr_t* mtr)
+{
+	ulint		len;
+	fil_addr_t	node_addr;
+	trx_rsegf_t*	rseg_header;
+	trx_ulogf_t*	undo_log_hdr;
+	ulint		sum_of_undo_sizes;
 
-	rseg_header = trx_rsegf_get_new(space, page_no, mtr);
+	rseg_header = trx_rsegf_get_new(rseg->space, rseg->page_no, mtr);
 
 	rseg->max_size = mtr_read_ulint(
 		rseg_header + TRX_RSEG_MAX_SIZE, MLOG_4BYTES, mtr);
@@ -240,8 +232,6 @@ trx_rseg_mem_create(
 
 			purge_sys->purge_queue.push(elem);
 		}
-	} else {
-		rseg->last_page_no = FIL_NULL;
 	}
 }
 
@@ -252,54 +242,45 @@ trx_rseg_array_init()
 	mtr_t	mtr;
 
 	for (ulint i = 0; i < TRX_SYS_N_RSEGS; i++) {
-		ut_ad(!trx_rseg_get_on_id(i));
 		mtr.start();
 		trx_sysf_t*	sys_header = trx_sysf_get(&mtr);
 		ulint		page_no = trx_sysf_rseg_get_page_no(
 			sys_header, i, &mtr);
 
 		if (page_no != FIL_NULL) {
-			trx_rseg_mem_create(
+			trx_rseg_t* rseg = trx_rseg_mem_create(
 				i,
 				trx_sysf_rseg_get_space(sys_header, i, &mtr),
-				page_no, &mtr);
+				page_no);
+			ut_ad(rseg->is_persistent());
+			ut_ad(!trx_sys->rseg_array[rseg->id]);
+			trx_sys->rseg_array[rseg->id] = rseg;
+			trx_rseg_mem_restore(rseg, &mtr);
 		}
 
 		mtr.commit();
 	}
 }
 
-/*********************************************************************
-Creates a rollback segment.
-@return pointer to new rollback segment if create successful */
+/** Create a persistent rollback segment.
+@param[in]	space_id	system or undo tablespace id */
 trx_rseg_t*
-trx_rseg_create(
-/*============*/
-	ulint	space_id,	/*!< in: id of UNDO tablespace */
-	ulint	nth_free_slot)	/*!< in: allocate nth free slot.
-				0 means next free slots. */
+trx_rseg_create(ulint space_id)
 {
-	mtr_t		mtr;
+	trx_rseg_t*		rseg = NULL;
+	mtr_t			mtr;
 
 	mtr.start();
 
 	/* To obey the latching order, acquire the file space
 	x-latch before the trx_sys->mutex. */
-	const fil_space_t*	space = mtr_x_lock_space(space_id, &mtr);
+#ifdef UNIV_DEBUG
+	const fil_space_t*	space =
+#endif /* UNIV_DEBUG */
+		mtr_x_lock_space(space_id, &mtr);
+	ut_ad(space->purpose == FIL_TYPE_TABLESPACE);
 
-	switch (space->purpose) {
-	case FIL_TYPE_LOG:
-	case FIL_TYPE_IMPORT:
-		ut_ad(0);
-	case FIL_TYPE_TEMPORARY:
-		mtr.set_log_mode(MTR_LOG_NO_REDO);
-		break;
-	case FIL_TYPE_TABLESPACE:
-		break;
-	}
-
-	ulint	slot_no = trx_sysf_rseg_find_free(
-		&mtr, space->purpose == FIL_TYPE_TEMPORARY, nth_free_slot);
+	ulint	slot_no = trx_sysf_rseg_find_free(&mtr);
 	ulint	page_no = slot_no == ULINT_UNDEFINED
 		? FIL_NULL
 		: trx_rseg_header_create(space_id, ULINT_MAX, slot_no, &mtr);
@@ -309,14 +290,45 @@ trx_rseg_create(
 
 		ulint		id = trx_sysf_rseg_get_space(
 			sys_header, slot_no, &mtr);
-		ut_a(id == space_id || trx_sys_is_noredo_rseg_slot(slot_no));
+		ut_a(id == space_id);
 
-		trx_rseg_mem_create(slot_no, space_id, page_no, &mtr);
+		rseg = trx_rseg_mem_create(slot_no, space_id, page_no);
+		ut_ad(rseg->is_persistent());
+		ut_ad(!trx_sys->rseg_array[rseg->id]);
+		trx_sys->rseg_array[rseg->id] = rseg;
+		trx_rseg_mem_restore(rseg, &mtr);
 	}
 
 	mtr.commit();
 
-	return(page_no == FIL_NULL ? NULL : trx_sys->rseg_array[slot_no]);
+	return(rseg);
+}
+
+/** Create the temporary rollback segments. */
+void
+trx_temp_rseg_create()
+{
+	mtr_t		mtr;
+
+	for (ulong i = 0; i < TRX_SYS_N_RSEGS; i++) {
+		mtr.start();
+		mtr.set_log_mode(MTR_LOG_NO_REDO);
+#ifdef UNIV_DEBUG
+		const fil_space_t*	space =
+#endif /* UNIV_DEBUG */
+			mtr_x_lock_space(SRV_TMP_SPACE_ID, &mtr);
+		ut_ad(space->purpose == FIL_TYPE_TEMPORARY);
+
+		ulint page_no = trx_rseg_header_create(
+			SRV_TMP_SPACE_ID, ULINT_MAX, i, &mtr);
+		trx_rseg_t* rseg = trx_rseg_mem_create(
+			i, SRV_TMP_SPACE_ID, page_no);
+		ut_ad(!rseg->is_persistent());
+		ut_ad(!trx_sys->temp_rsegs[i]);
+		trx_sys->temp_rsegs[i] = rseg;
+		trx_rseg_mem_restore(rseg, &mtr);
+		mtr.commit();
+	}
 }
 
 /********************************************************************
diff --git a/storage/innobase/trx/trx0sys.cc b/storage/innobase/trx/trx0sys.cc
index f08736ae1f128..24983dcc2a3bc 100644
--- a/storage/innobase/trx/trx0sys.cc
+++ b/storage/innobase/trx/trx0sys.cc
@@ -394,76 +394,41 @@ trx_sys_read_wsrep_checkpoint(
 
 #endif /* WITH_WSREP */
 
-/****************************************************************//**
-Looks for a free slot for a rollback segment in the trx system file copy.
-@return slot index or ULINT_UNDEFINED if not found */
+/** @return an unallocated rollback segment slot in the TRX_SYS header
+@retval ULINT_UNDEFINED if not found */
 ulint
-trx_sysf_rseg_find_free(
-/*====================*/
-	mtr_t*	mtr,			/*!< in/out: mtr */
-	bool	include_tmp_slots,	/*!< in: if true, report slots reserved
-					for temp-tablespace as free slots. */
-	ulint	nth_free_slots)		/*!< in: allocate nth free slot.
-					0 means next free slot. */
+trx_sysf_rseg_find_free(mtr_t* mtr)
 {
-	ulint		i;
-	trx_sysf_t*	sys_header;
-
-	sys_header = trx_sysf_get(mtr);
-
-	ulint	found_free_slots = 0;
-	for (i = 0; i < TRX_SYS_N_RSEGS; i++) {
-		ulint	page_no;
-
-		if (!include_tmp_slots && trx_sys_is_noredo_rseg_slot(i)) {
-			continue;
-		}
-
-		page_no = trx_sysf_rseg_get_page_no(sys_header, i, mtr);
+	trx_sysf_t*	sys_header = trx_sysf_get(mtr);
 
-		if (page_no == FIL_NULL
-		    || (include_tmp_slots
-			&& trx_sys_is_noredo_rseg_slot(i))) {
-
-			if (found_free_slots++ >= nth_free_slots) {
-				return(i);
-			}
+	for (ulint i = 0; i < TRX_SYS_N_RSEGS; i++) {
+		if (trx_sysf_rseg_get_page_no(sys_header, i, mtr)
+		    == FIL_NULL) {
+			return(i);
 		}
 	}
 
 	return(ULINT_UNDEFINED);
 }
 
-/****************************************************************//**
-Looks for used slots for redo rollback segment.
-@return number of used slots */
+/** Count the number of initialized persistent rollback segment slots. */
 static
-ulint
-trx_sysf_used_slots_for_redo_rseg(
-/*==============================*/
-	mtr_t*	mtr)			/*!< in: mtr */
+void
+trx_sysf_get_n_rseg_slots()
 {
-	trx_sysf_t*	sys_header;
-	ulint		n_used = 0;
+	mtr_t		mtr;
+	mtr.start();
 
-	sys_header = trx_sysf_get(mtr);
+	trx_sysf_t*	sys_header	= trx_sysf_get(&mtr);
+	srv_available_undo_logs = 0;
 
 	for (ulint i = 0; i < TRX_SYS_N_RSEGS; i++) {
-
-		if (trx_sys_is_noredo_rseg_slot(i)) {
-			continue;
-		}
-
-		ulint	page_no;
-
-		page_no = trx_sysf_rseg_get_page_no(sys_header, i, mtr);
-
-		if (page_no != FIL_NULL) {
-			++n_used;
-		}
+		srv_available_undo_logs
+			+= trx_sysf_rseg_get_page_no(sys_header, i, &mtr)
+			!= FIL_NULL;
 	}
 
-	return(n_used);
+	mtr.commit();
 }
 
 /*****************************************************************//**
@@ -532,7 +497,7 @@ trx_sysf_create(
 			+ page - sys_header, mtr);
 
 	/* Create the first rollback segment in the SYSTEM tablespace */
-	slot_no = trx_sysf_rseg_find_free(mtr, false, 0);
+	slot_no = trx_sysf_rseg_find_free(mtr);
 	page_no = trx_rseg_header_create(TRX_SYS_SPACE,
 					 ULINT_MAX, slot_no, mtr);
 
@@ -904,118 +869,69 @@ trx_sys_file_format_close(void)
 	mutex_free(&file_format_max.mutex);
 }
 
-/*********************************************************************
-Creates non-redo rollback segments.
-@return number of non-redo rollback segments created. */
-static
-ulint
-trx_sys_create_noredo_rsegs(
-/*========================*/
-	ulint	n_nonredo_rseg)	/*!< number of non-redo rollback segment
-				to create. */
-{
-	ulint n_created = 0;
-
-	/* Create non-redo rollback segments residing in temp-tablespace.
-	non-redo rollback segments don't perform redo logging and so
-	are used for undo logging of objects/table that don't need to be
-	recover on crash.
-	(Non-Redo rollback segments are created on every server startup).
-	Slot-0: reserved for system-tablespace.
-	Slot-1....Slot-N: reserved for temp-tablespace.
-	Slot-N+1....Slot-127: reserved for system/undo-tablespace. */
-	for (ulint i = 0; i < n_nonredo_rseg; i++) {
-		if (trx_rseg_create(SRV_TMP_SPACE_ID, i) == NULL) {
-			break;
-		}
-		++n_created;
-	}
-
-	return(n_created);
-}
-
-/*********************************************************************
-Creates the rollback segments.
-@return number of rollback segments that are active. */
-ulint
-trx_sys_create_rsegs(
-/*=================*/
-	ulint	n_spaces,	/*!< number of tablespaces for UNDO logs */
-	ulint	n_rsegs,	/*!< number of rollback segments to create */
-	ulint	n_tmp_rsegs)	/*!< number of rollback segments reserved for
-				temp-tables. */
+/** Create the rollback segments.
+@return	whether the creation succeeded */
+bool
+trx_sys_create_rsegs()
 {
-	mtr_t	mtr;
-	ulint	n_used;
-	ulint	n_noredo_created;
+	/* srv_available_undo_logs reflects the number of persistent
+	rollback segments that have been initialized in the
+	transaction system header page.
 
-	ut_a(n_spaces < TRX_SYS_N_RSEGS);
-	ut_a(n_rsegs <= TRX_SYS_N_RSEGS);
-	ut_a(n_tmp_rsegs > 0 && n_tmp_rsegs < TRX_SYS_N_RSEGS);
+	srv_undo_logs determines how many of the
+	srv_available_undo_logs rollback segments may be used for
+	logging new transactions. */
+	ut_ad(srv_undo_tablespaces < TRX_SYS_N_RSEGS);
+	ut_ad(srv_undo_logs <= TRX_SYS_N_RSEGS);
 
 	if (srv_read_only_mode) {
-		return(ULINT_UNDEFINED);
+		srv_undo_logs = srv_available_undo_logs = ULONG_UNDEFINED;
+		return(true);
 	}
 
-	/* Create non-redo rollback segments. */
-	n_noredo_created = trx_sys_create_noredo_rsegs(n_tmp_rsegs);
+	/* Create temporary rollback segments. */
+	trx_temp_rseg_create();
 
 	/* This is executed in single-threaded mode therefore it is not
 	necessary to use the same mtr in trx_rseg_create(). n_used cannot
 	change while the function is executing. */
-	mtr_start(&mtr);
-	n_used = trx_sysf_used_slots_for_redo_rseg(&mtr) + n_noredo_created;
-	mtr_commit(&mtr);
+	trx_sysf_get_n_rseg_slots();
 
-	ut_ad(n_used <= TRX_SYS_N_RSEGS);
+	ut_ad(srv_available_undo_logs <= TRX_SYS_N_RSEGS);
 
-	/* By default 1 redo rseg is always active that is hosted in
-	system tablespace. */
-	ulint	n_redo_active;
-	if (n_rsegs <= n_tmp_rsegs) {
-		n_redo_active = 1;
-	} else if (n_rsegs > n_used) {
-		n_redo_active = n_used - n_tmp_rsegs;
-	} else {
-		n_redo_active = n_rsegs - n_tmp_rsegs;
-	}
-
-	/* Do not create additional rollback segments if innodb_force_recovery
-	has been set and the database was not shutdown cleanly. */
-	if (!srv_force_recovery && !recv_needed_recovery && n_used < n_rsegs) {
-		ulint	i;
-		ulint	new_rsegs = n_rsegs - n_used;
-
-		for (i = 0; i < new_rsegs; ++i) {
-			ulint	space;
-
-			/* Tablespace 0 is the system tablespace. All UNDO
-			log tablespaces start from 1. */
+	/* The first persistent rollback segment is always initialized
+	in the system tablespace. */
+	ut_a(srv_available_undo_logs > 0);
 
-			if (n_spaces > 0) {
-				space = (i % n_spaces) + 1;
-			} else {
-				space = 0; /* System tablespace */
-			}
-
-			if (trx_rseg_create(space, 0) != NULL) {
-				++n_used;
-				++n_redo_active;
-			} else {
-				break;
+	if (srv_force_recovery) {
+		/* Do not create additional rollback segments if
+		innodb_force_recovery has been set. */
+		if (srv_undo_logs > srv_available_undo_logs) {
+			srv_undo_logs = srv_available_undo_logs;
+		}
+	} else {
+		for (ulint i = 0; srv_available_undo_logs < srv_undo_logs;
+		     i++, srv_available_undo_logs++) {
+			/* Tablespace 0 is the system tablespace.
+			Dedicated undo log tablespaces start from 1. */
+			ulint space = srv_undo_tablespaces > 0
+				? (i % srv_undo_tablespaces) + 1
+				: TRX_SYS_SPACE;
+
+			if (!trx_rseg_create(space)) {
+				ib::error() << "Unable to allocate the"
+					" requested innodb_undo_logs";
+				return(false);
 			}
 		}
 	}
 
-	ib::info() << n_used - srv_tmp_undo_logs
-		<< " redo rollback segment(s) found. "
-		<< n_redo_active
-		<< " redo rollback segment(s) are active.";
+	ut_ad(srv_undo_logs <= srv_available_undo_logs);
 
-	ib::info() << n_noredo_created << " non-redo rollback segment(s) are"
-		" active.";
+	ib::info() << srv_undo_logs << " out of " << srv_available_undo_logs
+		<< " rollback segments are active.";
 
-	return(n_used);
+	return(true);
 }
 
 /*********************************************************************
@@ -1027,9 +943,7 @@ trx_sys_close(void)
 	ut_ad(trx_sys != NULL);
 	ut_ad(srv_shutdown_state == SRV_SHUTDOWN_EXIT_THREADS);
 
-	ulint	size = trx_sys->mvcc->size();
-
-	if (size > 0) {
+	if (ulint size = trx_sys->mvcc->size()) {
 		ib::error() << "All read views were not closed before"
 			" shutdown: " << size << " read views open";
 	}
@@ -1060,6 +974,10 @@ trx_sys_close(void)
 		if (trx_rseg_t* rseg = trx_sys->rseg_array[i]) {
 			trx_rseg_mem_free(rseg);
 		}
+
+		if (trx_rseg_t* rseg = trx_sys->temp_rsegs[i]) {
+			trx_rseg_mem_free(rseg);
+		}
 	}
 
 	UT_DELETE(trx_sys->mvcc);
diff --git a/storage/innobase/trx/trx0trx.cc b/storage/innobase/trx/trx0trx.cc
index b687f8e899020..db09f7894a71e 100644
--- a/storage/innobase/trx/trx0trx.cc
+++ b/storage/innobase/trx/trx0trx.cc
@@ -1090,42 +1090,33 @@ trx_lists_init_at_db_start()
 	}
 }
 
-/******************************************************************//**
-Get next redo rollback segment. (Segment are assigned in round-robin fashion).
-@return assigned rollback segment instance */
+/** Assign a persistent rollback segment in a round-robin fashion,
+evenly distributed between 0 and innodb_undo_logs-1
+@return	persistent rollback segment
+@retval	NULL	if innodb_read_only */
 static
 trx_rseg_t*
-get_next_redo_rseg(
-/*===============*/
-	ulong	max_undo_logs,	/*!< in: maximum number of UNDO logs to use */
-	ulint	n_tablespaces)	/*!< in: number of rollback tablespaces */
+trx_assign_rseg_low()
 {
-	trx_rseg_t*	rseg;
-	static ulint	redo_rseg_slot = 0;
-	ulint		slot = 0;
-
-	slot = redo_rseg_slot++;
-	slot = slot % max_undo_logs;
-
-	/* Skip slots alloted to non-redo also ensure even distribution
-	in selecting next redo slots.
-	For example: If we don't do even distribution then for any value of
-	slot between 1 - 32 ... 33rd slots will be alloted creating
-	skewed distribution. */
-	if (trx_sys_is_noredo_rseg_slot(slot)) {
-
-		if (max_undo_logs > srv_tmp_undo_logs) {
+	if (srv_read_only_mode) {
+		ut_ad(srv_undo_logs == ULONG_UNDEFINED);
+		return(NULL);
+	}
 
-			slot %= (max_undo_logs - srv_tmp_undo_logs);
+	/* The first slot is always assigned to the system tablespace. */
+	ut_ad(trx_sys->rseg_array[0]->space == TRX_SYS_SPACE);
 
-			if (trx_sys_is_noredo_rseg_slot(slot)) {
-				slot += srv_tmp_undo_logs;
-			}
+	/* Choose a rollback segment evenly distributed between 0 and
+	innodb_undo_logs-1 in a round-robin fashion, skipping those
+	undo tablespaces that are scheduled for truncation.
 
-		} else {
-			slot = 0;
-		}
-	}
+	Because rseg_slot is not protected by atomics or any mutex, race
+	conditions are possible, meaning that multiple transactions
+	that start modifications concurrently will write their undo
+	log to the same rollback segment. */
+	static ulong	rseg_slot;
+	ulint		slot = rseg_slot++ % srv_undo_logs;
+	trx_rseg_t*	rseg;
 
 #ifdef UNIV_DEBUG
 	ulint	start_scan_slot = slot;
@@ -1134,8 +1125,7 @@ get_next_redo_rseg(
 
 	bool	allocated = false;
 
-	while (!allocated) {
-
+	do {
 		for (;;) {
 			rseg = trx_sys->rseg_array[slot];
 
@@ -1148,37 +1138,31 @@ get_next_redo_rseg(
 			look_for_rollover = true;
 #endif /* UNIV_DEBUG */
 
-			slot = (slot + 1) % max_undo_logs;
-
-			/* Skip slots allocated for noredo rsegs */
-			while (trx_sys_is_noredo_rseg_slot(slot)) {
-				slot = (slot + 1) % max_undo_logs;
-			}
+			slot = (slot + 1) % srv_undo_logs;
 
 			if (rseg == NULL) {
 				continue;
-			} else if (rseg->space == srv_sys_space.space_id()
-				   && n_tablespaces > 0
-				   && trx_sys->rseg_array[slot] != NULL
-				   && trx_sys->rseg_array[slot]->space
-					!= srv_sys_space.space_id()) {
-				/** If undo-tablespace is configured, skip
-				rseg from system-tablespace and try to use
-				undo-tablespace rseg unless it is not possible
-				due to lower limit of undo-logs. */
-				continue;
-			} else if (rseg->skip_allocation) {
-				/** This rseg resides in the tablespace that
-				has been marked for truncate so avoid using this
-				rseg. Also, this is possible only if there are
-				at-least 2 UNDO tablespaces active and 2 redo
-				rsegs active (other than default system bound
-				rseg-0). */
-				ut_ad(n_tablespaces > 1);
-				ut_ad(max_undo_logs
-					>= (1 + srv_tmp_undo_logs + 2));
-				continue;
 			}
+
+			ut_ad(rseg->is_persistent());
+
+			if (rseg->space != TRX_SYS_SPACE) {
+				ut_ad(srv_undo_tablespaces > 1);
+				if (rseg->skip_allocation) {
+					continue;
+				}
+			} else if (trx_rseg_t* next
+				   = trx_sys->rseg_array[slot]) {
+				if (next->space != TRX_SYS_SPACE
+				    && srv_undo_tablespaces > 0) {
+					/** If dedicated
+					innodb_undo_tablespaces have
+					been configured, try to use them
+					instead of the system tablespace. */
+					continue;
+				}
+			}
+
 			break;
 		}
 
@@ -1191,129 +1175,43 @@ get_next_redo_rseg(
 			allocated = true;
 		}
 		mutex_exit(&rseg->mutex);
-	}
+	} while (!allocated);
 
 	ut_ad(rseg->trx_ref_count > 0);
-	ut_ad(!trx_sys_is_noredo_rseg_slot(rseg->id));
-	return(rseg);
-}
-
-/******************************************************************//**
-Get next noredo rollback segment.
-@return assigned rollback segment instance */
-static
-trx_rseg_t*
-get_next_noredo_rseg(
-/*=================*/
-	ulong	max_undo_logs)	/*!< in: maximum number of UNDO logs to use */
-{
-	trx_rseg_t*	rseg;
-	static ulint	noredo_rseg_slot = 1;
-	ulint		slot = 0;
-
-	slot = noredo_rseg_slot++;
-	slot = slot % max_undo_logs;
-	while (!trx_sys_is_noredo_rseg_slot(slot)) {
-		slot = (slot + 1) % max_undo_logs;
-	}
-
-	for (;;) {
-		rseg = trx_sys->rseg_array[slot];
-
-		slot = (slot + 1) % max_undo_logs;
-
-		while (!trx_sys_is_noredo_rseg_slot(slot)) {
-			slot = (slot + 1) % max_undo_logs;
-		}
-
-		if (rseg != NULL) {
-			break;
-		}
-	}
-
-	ut_ad(fsp_is_system_temporary(rseg->space));
-	ut_ad(trx_sys_is_noredo_rseg_slot(rseg->id));
+	ut_ad(rseg->is_persistent());
 	return(rseg);
 }
 
-/******************************************************************//**
-Assigns a rollback segment to a transaction in a round-robin fashion.
-@return assigned rollback segment instance */
-static
+/** Assign a rollback segment for modifying temporary tables.
+@return the assigned rollback segment */
 trx_rseg_t*
-trx_assign_rseg_low(
-/*================*/
-	ulong		max_undo_logs,	/*!< in: maximum number of UNDO logs
-					to use */
-	ulint		n_tablespaces,	/*!< in: number of rollback
-					tablespaces */
-	trx_rseg_type_t	rseg_type)	/*!< in: type of rseg to assign. */
-{
-	if (srv_read_only_mode) {
-		ut_a(max_undo_logs == ULONG_UNDEFINED);
-		return(NULL);
-	}
-
-	/* This breaks true round robin but that should be OK. */
-	ut_ad(max_undo_logs > 0 && max_undo_logs <= TRX_SYS_N_RSEGS);
-
-	/* Note: The assumption here is that there can't be any gaps in
-	the array. Once we implement more flexible rollback segment
-	management this may not hold. The assertion checks for that case. */
-	ut_ad(trx_sys->rseg_array[0] != NULL);
-	ut_ad(rseg_type == TRX_RSEG_TYPE_REDO
-	      || trx_sys->rseg_array[1] != NULL);
-
-	/* Slot-0 is always assigned to system-tablespace rseg. */
-	ut_ad(trx_sys->rseg_array[0]->space == srv_sys_space.space_id());
-
-	/* Slot-1 is always assigned to temp-tablespace rseg. */
-	ut_ad(rseg_type == TRX_RSEG_TYPE_REDO
-	      || fsp_is_system_temporary(trx_sys->rseg_array[1]->space));
-
-	trx_rseg_t* rseg = 0;
-
-	switch (rseg_type) {
-	case TRX_RSEG_TYPE_NONE:
-		ut_error;
-
-	case TRX_RSEG_TYPE_REDO:
-		rseg = get_next_redo_rseg(max_undo_logs, n_tablespaces);
-		break;
-
-	case TRX_RSEG_TYPE_NOREDO:
-		rseg = get_next_noredo_rseg(srv_tmp_undo_logs + 1);
-		break;
-	}
-
-	return(rseg);
-}
-
-/****************************************************************//**
-Assign a transaction temp-tablespace bounded rollback-segment. */
-void
-trx_assign_rseg(
-/*============*/
-	trx_t*		trx)		/*!< transaction that involves write
-					to temp-table. */
-{
-	ut_a(trx->rsegs.m_noredo.rseg == 0);
-	ut_a(!trx_is_autocommit_non_locking(trx));
-
-	trx->rsegs.m_noredo.rseg = trx_assign_rseg_low(
-		srv_undo_logs, srv_undo_tablespaces, TRX_RSEG_TYPE_NOREDO);
-
-	if (trx->id == 0) {
+trx_t::assign_temp_rseg()
+{
+	ut_ad(!rsegs.m_noredo.rseg);
+	ut_ad(!trx_is_autocommit_non_locking(this));
+	compile_time_assert(ut_is_2pow(TRX_SYS_N_RSEGS));
+
+	/* Choose a temporary rollback segment between 0 and 127
+	in a round-robin fashion. Because rseg_slot is not protected by
+	atomics or any mutex, race conditions are possible, meaning that
+	multiple transactions that start modifications concurrently
+	will write their undo log to the same rollback segment. */
+	static ulong	rseg_slot;
+	trx_rseg_t*	rseg = trx_sys->temp_rsegs[
+		rseg_slot++ & (TRX_SYS_N_RSEGS - 1)];
+	ut_ad(!rseg->is_persistent());
+	rsegs.m_noredo.rseg = rseg;
+
+	if (id == 0) {
 		mutex_enter(&trx_sys->mutex);
-
-		trx->id = trx_sys_get_new_trx_id();
-
-		trx_sys->rw_trx_ids.push_back(trx->id);
-
-		trx_sys->rw_trx_set.insert(TrxTrack(trx->id, trx));
-
+		id = trx_sys_get_new_trx_id();
+		trx_sys->rw_trx_ids.push_back(id);
+		trx_sys->rw_trx_set.insert(TrxTrack(id, this));
 		mutex_exit(&trx_sys->mutex);
 	}
+
+	ut_ad(!rseg->is_persistent());
+	return(rseg);
 }
 
 /****************************************************************//**
@@ -1388,9 +1286,7 @@ trx_start_low(
 	if (!trx->read_only
 	    && (trx->mysql_thd == 0 || read_write || trx->ddl)) {
 
-		trx->rsegs.m_redo.rseg = trx_assign_rseg_low(
-			srv_undo_logs, srv_undo_tablespaces,
-			TRX_RSEG_TYPE_REDO);
+		trx->rsegs.m_redo.rseg = trx_assign_rseg_low();
 
 		/* Temporary rseg is assigned only if the transaction
 		updates a temporary table */
@@ -2969,8 +2865,6 @@ trx_start_if_not_started_xa_low(
 			trx_sys_t::rw_trx_list. */
 			if (!trx->read_only) {
 				trx_set_rw_mode(trx);
-			} else if (!srv_read_only_mode) {
-				trx_assign_rseg(trx);
 			}
 		}
 		return;
@@ -3116,8 +3010,7 @@ trx_set_rw_mode(
 	that both threads are synced by acquring trx->mutex to avoid decision
 	based on in-consistent view formed during promotion. */
 
-	trx->rsegs.m_redo.rseg = trx_assign_rseg_low(
-		srv_undo_logs, srv_undo_tablespaces, TRX_RSEG_TYPE_REDO);
+	trx->rsegs.m_redo.rseg = trx_assign_rseg_low();
 
 	ut_ad(trx->rsegs.m_redo.rseg != 0);
 
diff --git a/storage/innobase/trx/trx0undo.cc b/storage/innobase/trx/trx0undo.cc
index 92e18c1c37202..3eab3733f8fdf 100644
--- a/storage/innobase/trx/trx0undo.cc
+++ b/storage/innobase/trx/trx0undo.cc
@@ -1027,7 +1027,7 @@ void
 trx_undo_truncate_end(trx_undo_t* undo, undo_no_t limit, bool is_temp)
 {
 	ut_ad(mutex_own(&undo->rseg->mutex));
-	ut_ad(is_temp == trx_sys_is_noredo_rseg_slot(undo->rseg->id));
+	ut_ad(is_temp == !undo->rseg->is_persistent());
 
 	for (;;) {
 		mtr_t		mtr;
@@ -1102,7 +1102,7 @@ trx_undo_truncate_start(
 loop:
 	mtr_start(&mtr);
 
-	if (trx_sys_is_noredo_rseg_slot(rseg->id)) {
+	if (!rseg->is_persistent()) {
 		mtr.set_log_mode(MTR_LOG_NO_REDO);
 	}
 
@@ -1856,7 +1856,7 @@ void
 trx_undo_commit_cleanup(trx_undo_t* undo, bool is_temp)
 {
 	trx_rseg_t*	rseg	= undo->rseg;
-	ut_ad(is_temp == trx_sys_is_noredo_rseg_slot(rseg->id));
+	ut_ad(is_temp == !rseg->is_persistent());
 
 	mutex_enter(&rseg->mutex);