BUG#29203 - archive tables have weird values in show table status

Archive engine returns wrong values for average record length
and max data length.

With this fix they're calculated as following:
- max data length is 2 ^ 63 where large files are supported
  and INT_MAX32 where this is not supported;
- average record length is data length / records in data file.

mysql-test/r/archive.result:
  A test case for BUG#29203.
mysql-test/t/archive.test:
  A test case for BUG#29203.
storage/archive/ha_archive.cc:
  Better estimation for average row length and maximal data
  file length.

mysql-test/r/archive.result

@@ -12695,3 +12695,14 @@ a	b
 1	NULL
 2	NULL
 DROP TABLE t1;
+CREATE TABLE t1(a INT, b BLOB) ENGINE=archive;
+SELECT DATA_LENGTH, AVG_ROW_LENGTH FROM
+INFORMATION_SCHEMA.TABLES WHERE TABLE_NAME='t1' AND TABLE_SCHEMA='test';
+DATA_LENGTH	AVG_ROW_LENGTH
+8666	15
+INSERT INTO t1 VALUES(1, 'sampleblob1'),(2, 'sampleblob2');
+SELECT DATA_LENGTH, AVG_ROW_LENGTH FROM
+INFORMATION_SCHEMA.TABLES WHERE TABLE_NAME='t1' AND TABLE_SCHEMA='test';
+DATA_LENGTH	AVG_ROW_LENGTH
+8700	4350
+DROP TABLE t1;

mysql-test/t/archive.test

@@ -1599,3 +1599,14 @@ INSERT INTO t1 VALUES (NULL, NULL),(NULL, NULL);
 FLUSH TABLE t1;
 SELECT * FROM t1 ORDER BY a;
 DROP TABLE t1;
+
+#
+# BUG#29203 - archive tables have weird values in show table status
+#
+CREATE TABLE t1(a INT, b BLOB) ENGINE=archive;
+SELECT DATA_LENGTH, AVG_ROW_LENGTH FROM
+  INFORMATION_SCHEMA.TABLES WHERE TABLE_NAME='t1' AND TABLE_SCHEMA='test';
+INSERT INTO t1 VALUES(1, 'sampleblob1'),(2, 'sampleblob2');
+SELECT DATA_LENGTH, AVG_ROW_LENGTH FROM
+  INFORMATION_SCHEMA.TABLES WHERE TABLE_NAME='t1' AND TABLE_SCHEMA='test';
+DROP TABLE t1;

storage/archive/ha_archive.cc

@@ -1472,11 +1472,12 @@ int ha_archive::info(uint flag)
 
     VOID(my_stat(share->data_file_name, &file_stat, MYF(MY_WME)));
 
-    stats.mean_rec_length= table->s->reclength + buffer.alloced_length();
     stats.data_file_length= file_stat.st_size;
     stats.create_time= (ulong) file_stat.st_ctime;
     stats.update_time= (ulong) file_stat.st_mtime;
-    stats.max_data_file_length= share->rows_recorded * stats.mean_rec_length;
+    stats.mean_rec_length= stats.records ?
+      stats.data_file_length / stats.records : table->s->reclength;
+    stats.max_data_file_length= MAX_FILE_SIZE;
   }
   stats.delete_length= 0;
   stats.index_file_length=0;