MDEV-7273 - 10.1 fails to start up during tc_log initializations on PPC64

log-tc-size is 24K by default. Page size is 64K on PPC64. But log-tc-
size
must be at least 3 x page size. This is enforced by TC_LOG_MMAP::open()
with a comment: to guarantee non-empty pool.

This all makes server not startable in default configuration on PPC64.

Autosize log-tc-size, so that it's min value= page size * 3, default
value= page size * 6, block size= page size.

Conflicts:
	mysql-test/suite/sys_vars/inc/sysvars_server.inc
	mysql-test/suite/sys_vars/r/sysvars_server_notembedded.result
	mysql-test/t/mysqld--help.test
	sql/mysqld.cc
	sql/sys_vars.cc

mysql-test/r/mysqld--help.result

@@ -1248,7 +1248,6 @@ log-slow-rate-limit 1
 log-slow-slave-statements FALSE
 log-slow-verbosity 
 log-tc tc.log
-log-tc-size 24576
 log-warnings 1
 long-query-time 10
 low-priority-updates FALSE

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

@@ -0,0 +1,4 @@
+SET GLOBAL log_tc_size=1;
+ERROR HY000: Variable 'log_tc_size' is a read only variable
+SET SESSION log_tc_size=1;
+ERROR HY000: Variable 'log_tc_size' is a read only variable

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

@@ -0,0 +1,5 @@
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET GLOBAL log_tc_size=1;
+
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET SESSION log_tc_size=1;

mysql-test/t/mysqld--help.test

@@ -22,7 +22,7 @@ perl;
                log-slow-queries pid-file slow-query-log-file log-basename
                datadir slave-load-tmpdir tmpdir socket thread-pool-size
                large-files-support lower-case-file-system system-time-zone
-               wsrep-node-name wsrep-data-home-dir version.*/;
+               wsrep-node-name wsrep-data-home-dir log-tc-size version.*/;
 
   # Plugins which may or may not be there:
   @plugins=qw/innodb ndb archive blackhole federated partition ndbcluster

sql/log.cc

@@ -8432,7 +8432,7 @@ ulong tc_log_page_waits= 0;
 
 static const uchar tc_log_magic[]={(uchar) 254, 0x23, 0x05, 0x74};
 
-ulong opt_tc_log_size= TC_LOG_MIN_SIZE;
+ulong opt_tc_log_size;
 ulong tc_log_max_pages_used=0, tc_log_page_size=0, tc_log_cur_pages_used=0;
 
 int TC_LOG_MMAP::open(const char *opt_name)
@@ -8445,7 +8445,6 @@ int TC_LOG_MMAP::open(const char *opt_name)
   DBUG_ASSERT(opt_name && opt_name[0]);
 
   tc_log_page_size= my_getpagesize();
-  DBUG_ASSERT(TC_LOG_PAGE_SIZE % tc_log_page_size == 0);
 
   fn_format(logname,opt_name,mysql_data_home,"",MY_UNPACK_FILENAME);
   if ((fd= mysql_file_open(key_file_tclog, logname, O_RDWR, MYF(0))) < 0)
@@ -8784,6 +8783,7 @@ mmap_do_checkpoint_callback(void *data)
 int TC_LOG_MMAP::unlog(ulong cookie, my_xid xid)
 {
   pending_cookies *full_buffer= NULL;
+  uint32 ncookies= tc_log_page_size / sizeof(my_xid);
   DBUG_ASSERT(*(my_xid *)(data+cookie) == xid);
 
   /*
@@ -8797,7 +8797,7 @@ int TC_LOG_MMAP::unlog(ulong cookie, my_xid xid)
   mysql_mutex_lock(&LOCK_pending_checkpoint);
   if (pending_checkpoint == NULL)
   {
-    uint32 size= sizeof(*pending_checkpoint);
+    uint32 size= sizeof(*pending_checkpoint) + sizeof(ulong) * (ncookies - 1);
     if (!(pending_checkpoint=
           (pending_cookies *)my_malloc(size, MYF(MY_ZEROFILL))))
     {
@@ -8808,8 +8808,7 @@ int TC_LOG_MMAP::unlog(ulong cookie, my_xid xid)
   }
 
   pending_checkpoint->cookies[pending_checkpoint->count++]= cookie;
-  if (pending_checkpoint->count == sizeof(pending_checkpoint->cookies) /
-      sizeof(pending_checkpoint->cookies[0]))
+  if (pending_checkpoint->count == ncookies)
   {
     full_buffer= pending_checkpoint;
     pending_checkpoint= NULL;
@@ -8843,7 +8842,7 @@ TC_LOG_MMAP::commit_checkpoint_notify(void *cookie)
   if (count == 0)
   {
     uint i;
-    for (i= 0; i < sizeof(pending->cookies)/sizeof(pending->cookies[0]); ++i)
+    for (i= 0; i < tc_log_page_size / sizeof(my_xid); ++i)
       delete_entry(pending->cookies[i]);
     my_free(pending);
   }

sql/log.h

@@ -114,7 +114,6 @@ public:
 };
 
 #define TC_LOG_PAGE_SIZE   8192
-#define TC_LOG_MIN_SIZE    (3*TC_LOG_PAGE_SIZE)
 
 #ifdef HAVE_MMAP
 class TC_LOG_MMAP: public TC_LOG
@@ -129,7 +128,7 @@ class TC_LOG_MMAP: public TC_LOG
   struct pending_cookies {
     uint count;
     uint pending_count;
-    ulong cookies[TC_LOG_PAGE_SIZE/sizeof(my_xid)];
+    ulong cookies[1];
   };
 
   private:

sql/mysqld.cc

@@ -7698,12 +7698,6 @@ struct my_option my_long_options[]=
    "more than one storage engine, when binary log is disabled).",
    &opt_tc_log_file, &opt_tc_log_file, 0, GET_STR,
    REQUIRED_ARG, 0, 0, 0, 0, 0, 0},
-#ifdef HAVE_MMAP
-  {"log-tc-size", 0, "Size of transaction coordinator log.",
-   &opt_tc_log_size, &opt_tc_log_size, 0, GET_ULONG,
-   REQUIRED_ARG, TC_LOG_MIN_SIZE, TC_LOG_MIN_SIZE, (ulonglong) ULONG_MAX, 0,
-   TC_LOG_PAGE_SIZE, 0},
-#endif
   {"master-info-file", 0,
    "The location and name of the file that remembers the master and where "
    "the I/O replication thread is in the master's binlogs. Defaults to "

sql/sys_vars.cc

@@ -5107,3 +5107,13 @@ static Sys_var_mybool Sys_pseudo_slave_mode(
        SESSION_ONLY(pseudo_slave_mode), NO_CMD_LINE, DEFAULT(FALSE),
        NO_MUTEX_GUARD, NOT_IN_BINLOG, ON_CHECK(check_pseudo_slave_mode));
 
+#ifdef HAVE_MMAP
+static Sys_var_ulong Sys_log_tc_size(
+       "log_tc_size",
+       "Size of transaction coordinator log.",
+       READ_ONLY GLOBAL_VAR(opt_tc_log_size),
+       CMD_LINE(REQUIRED_ARG),
+       VALID_RANGE(my_getpagesize() * 3, ULONG_MAX),
+       DEFAULT(my_getpagesize() * 6),
+       BLOCK_SIZE(my_getpagesize()));
+#endif