Follow-up to MDEV-12289: Support innodb_undo_tablespaces=127

MySQL 5.7 reduced the maximum number of innodb_undo_tablespaces
from 126 to 95 when it reserved 32 persistent rollback segments
for the temporary undo logs. Since MDEV-12289 restored all 128
persistent rollback segments for persistent undo logs, the
reasonable maximum value of innodb_undo_tablespaces is 127
(not 126 or 95). This is because out of the 128 rollback segments,
the first one will always be created in the system tablespace
and the remaining ones can be created in dedicated undo tablespaces.

mysql-test/suite/sys_vars/r/sysvars_innodb,32bit.rdiff

@@ -571,9 +571,9 @@
  VARIABLE_SCOPE	GLOBAL
 -VARIABLE_TYPE	BIGINT UNSIGNED
 +VARIABLE_TYPE	INT UNSIGNED
- VARIABLE_COMMENT	Number of undo tablespaces to use. 
+ VARIABLE_COMMENT	Number of undo tablespaces to use.
  NUMERIC_MIN_VALUE	0
- NUMERIC_MAX_VALUE	95
+ NUMERIC_MAX_VALUE	127
 @@ -2630,7 +2630,7 @@
  GLOBAL_VALUE_ORIGIN	CONFIG
  DEFAULT_VALUE	4

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

@@ -2505,9 +2505,9 @@ GLOBAL_VALUE_ORIGIN	COMPILE-TIME
 DEFAULT_VALUE	0
 VARIABLE_SCOPE	GLOBAL
 VARIABLE_TYPE	BIGINT UNSIGNED
-VARIABLE_COMMENT	Number of undo tablespaces to use. 
+VARIABLE_COMMENT	Number of undo tablespaces to use.
 NUMERIC_MIN_VALUE	0
-NUMERIC_MAX_VALUE	95
+NUMERIC_MAX_VALUE	127
 NUMERIC_BLOCK_SIZE	0
 ENUM_VALUE_LIST	NULL
 READ_ONLY	YES

storage/innobase/handler/ha_innodb.cc

@@ -4487,7 +4487,7 @@ innobase_init(
 			os_thread_sleep(20);
 	}
 
-	srv_was_started = TRUE;
+	srv_was_started = true;
 	/* Adjust the innodb_undo_logs config object */
 	innobase_undo_logs_init_default_max();
 
@@ -21477,11 +21477,11 @@ static MYSQL_SYSVAR_STR(undo_directory, srv_undo_dir,
 
 static MYSQL_SYSVAR_ULONG(undo_tablespaces, srv_undo_tablespaces,
   PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
-  "Number of undo tablespaces to use. ",
+  "Number of undo tablespaces to use.",
   NULL, NULL,
   0L,			/* Default seting */
   0L,			/* Minimum value */
-  95L, 0);		/* Maximum value */
+  TRX_SYS_MAX_UNDO_SPACES, 0); /* Maximum value */
 
 static MYSQL_SYSVAR_ULONG(undo_logs, srv_undo_logs,
   PLUGIN_VAR_OPCMDARG,

storage/innobase/include/srv0srv.h

@@ -301,6 +301,9 @@ extern long    srv_mtflush_threads;
 /* If this flag is TRUE, then we will use multi threaded flush. */
 extern my_bool	srv_use_mtflush;
 
+/** TRUE if the server was successfully started */
+extern bool	srv_was_started;
+
 /** Server undo tablespaces directory, can be absolute path. */
 extern char*	srv_undo_dir;
 

storage/innobase/include/srv0start.h

@@ -121,8 +121,6 @@ extern	lsn_t	srv_start_lsn;
 extern	bool	srv_is_being_started;
 /** TRUE if SYS_TABLESPACES is available for lookups */
 extern	bool	srv_sys_tablespaces_open;
-/** TRUE if the server was successfully started */
-extern	ibool	srv_was_started;
 /** TRUE if the server is being started, before rolling back any
 incomplete transactions */
 extern	bool	srv_startup_is_before_trx_rollback_phase;

storage/innobase/include/trx0rseg.h

@@ -200,7 +200,10 @@ struct trx_rseg_t {
 	bool is_persistent() const
 	{
 		ut_ad(space == SRV_TMP_SPACE_ID
-		      || space <= srv_undo_tablespaces);
+		      || space <= TRX_SYS_MAX_UNDO_SPACES);
+		ut_ad(space == SRV_TMP_SPACE_ID
+		      || space <= srv_undo_tablespaces_active
+		      || !srv_was_started);
 		return(space != SRV_TMP_SPACE_ID);
 	}
 };

storage/innobase/include/trx0rseg.ic

@@ -42,7 +42,9 @@ trx_rsegf_get(
 	buf_block_t*	block;
 	trx_rsegf_t*	header;
 
-	ut_ad(space <= srv_undo_tablespaces || space == SRV_TMP_SPACE_ID);
+	ut_ad(space <= srv_undo_tablespaces_active || space == SRV_TMP_SPACE_ID
+	      || !srv_was_started);
+	ut_ad(space <= TRX_SYS_MAX_UNDO_SPACES || space == SRV_TMP_SPACE_ID);
 
 	block = buf_page_get(
 		page_id_t(space, page_no), univ_page_size, RW_X_LATCH, mtr);
@@ -69,7 +71,9 @@ trx_rsegf_get_new(
 	buf_block_t*	block;
 	trx_rsegf_t*	header;
 
-	ut_ad(space <= srv_undo_tablespaces || space == SRV_TMP_SPACE_ID);
+	ut_ad(space <= srv_undo_tablespaces_active || space == SRV_TMP_SPACE_ID
+	      || !srv_was_started);
+	ut_ad(space <= TRX_SYS_MAX_UNDO_SPACES || space == SRV_TMP_SPACE_ID);
 
 	block = buf_page_get(
 		page_id_t(space, page_no), univ_page_size, RW_X_LATCH, mtr);

storage/innobase/include/trx0sys.h

@@ -403,6 +403,8 @@ byte, therefore 128; each slot is currently 8 bytes in size. If you want
 to raise the level to 256 then you will need to fix some assertions that
 impose the 7 bit restriction. e.g., mach_write_to_3() */
 #define	TRX_SYS_N_RSEGS			128
+/** Maximum number of undo tablespaces (not counting the system tablespace) */
+#define TRX_SYS_MAX_UNDO_SPACES		(TRX_SYS_N_RSEGS - 1)
 
 /** Maximum length of MySQL binlog file name, in bytes. */
 #define TRX_SYS_MYSQL_LOG_NAME_LEN	512

storage/innobase/srv/srv0start.cc

@@ -121,22 +121,22 @@ lsn_t	srv_start_lsn;
 lsn_t	srv_shutdown_lsn;
 
 /** TRUE if a raw partition is in use */
-ibool	srv_start_raw_disk_in_use = FALSE;
+ibool	srv_start_raw_disk_in_use;
 
 /** Number of IO threads to use */
-ulint	srv_n_file_io_threads = 0;
+ulint	srv_n_file_io_threads;
 
 /** TRUE if the server is being started, before rolling back any
 incomplete transactions */
-bool	srv_startup_is_before_trx_rollback_phase = false;
+bool	srv_startup_is_before_trx_rollback_phase;
 /** TRUE if the server is being started */
-bool	srv_is_being_started = false;
+bool	srv_is_being_started;
 /** TRUE if SYS_TABLESPACES is available for lookups */
-bool	srv_sys_tablespaces_open = false;
+bool	srv_sys_tablespaces_open;
 /** TRUE if the server was successfully started */
-ibool	srv_was_started = FALSE;
+bool	srv_was_started;
 /** TRUE if innobase_start_or_create_for_mysql() has been called */
-static ibool	srv_start_has_been_called = FALSE;
+static bool	srv_start_has_been_called;
 #ifdef UNIV_DEBUG
 /** InnoDB system tablespace to set during recovery */
 UNIV_INTERN uint	srv_sys_space_size_debug;
@@ -1519,7 +1519,7 @@ innobase_start_or_create_for_mysql(void)
 			" once during the process lifetime.";
 	}
 
-	srv_start_has_been_called = TRUE;
+	srv_start_has_been_called = true;
 
 	srv_is_being_started = true;
 
@@ -2889,8 +2889,8 @@ innodb_shutdown()
 	}
 
 	srv_start_state = SRV_START_STATE_NONE;
-	srv_was_started = FALSE;
-	srv_start_has_been_called = FALSE;
+	srv_was_started = false;
+	srv_start_has_been_called = false;
 }
 
 #if 0 // TODO: Enable this in WL#6608

storage/innobase/trx/trx0sys.cc

@@ -879,7 +879,7 @@ trx_sys_create_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_tablespaces <= TRX_SYS_MAX_UNDO_SPACES);
 	ut_ad(srv_undo_logs <= TRX_SYS_N_RSEGS);
 
 	if (srv_read_only_mode) {