Patch for WL#3736: Extended Table, Column and Index Comments.

The task is to 
  (a) add a comment on indexes and 
  (b) increase the maximum length of column, table and the new index comments.

The patch committed on behalf of Yoshinori Matsunobu (Yoshinori.Matsunobu@Sun.COM).

1 files changed, 88 insertions, 41 deletions

diff --git a/sql/unireg.cc b/sql/unireg.cc
index b20e759efbb..c7d2f2f5b5b 100644
--- a/sql/unireg.cc
+++ b/sql/unireg.cc
@@ -188,27 +188,6 @@ bool mysql_create_frm(THD *thd, const char *file_name,
     if (key_info[i].parser_name)
       create_info->extra_size+= key_info[i].parser_name->length + 1;
   }
-
-  if ((file=create_frm(thd, file_name, db, table, reclength, fileinfo,
-		       create_info, keys)) < 0)
-  {
-    my_free(screen_buff, MYF(0));
-    DBUG_RETURN(1);
-  }
-
-  key_buff_length= uint4korr(fileinfo+47);
-  keybuff=(uchar*) my_malloc(key_buff_length, MYF(0));
-  key_info_length= pack_keys(keybuff, keys, key_info, data_offset);
-  (void) get_form_pos(file,fileinfo,&formnames);
-  if (!(filepos=make_new_entry(file,fileinfo,&formnames,"")))
-    goto err;
-  maxlength=(uint) next_io_size((ulong) (uint2korr(forminfo)+1000));
-  int2store(forminfo+2,maxlength);
-  int4store(fileinfo+10,(ulong) (filepos+maxlength));
-  fileinfo[26]= (uchar) test((create_info->max_rows == 1) &&
-			     (create_info->min_rows == 1) && (keys == 0));
-  int2store(fileinfo+28,key_info_length);
-
   /*
     This gives us the byte-position of the character at
     (character-position, not byte-position) TABLE_COMMENT_MAXLEN.
@@ -222,33 +201,78 @@ bool mysql_create_frm(THD *thd, const char *file_name,
     string), the string is too long.
 
     For additional credit, realise that UTF-8 has 1-3 bytes before 6.0,
-    and 1-4 bytes in 6.0 (6.0 also has UTF-32). This means that the
-    inlined COMMENT supposedly does not exceed 60 character plus
-    terminator, vulgo, 181 bytes.
+    and 1-4 bytes in 6.0 (6.0 also has UTF-32).
   */
-
   tmp_len= system_charset_info->cset->charpos(system_charset_info,
                                               create_info->comment.str,
                                               create_info->comment.str +
-                                              create_info->comment.length, 60);
+                                              create_info->comment.length,
+                                              TABLE_COMMENT_MAXLEN);
+
   if (tmp_len < create_info->comment.length)
   {
+    char *real_table_name= (char*) table;
+    List_iterator<Create_field> it(create_fields);
+    Create_field *field;
+    while ((field=it++))
+    {
+      if (field->field && field->field->table &&
+         (real_table_name= field->field->table->s->table_name.str))
+        break;
+    }
     if ((thd->variables.sql_mode &
          (MODE_STRICT_TRANS_TABLES | MODE_STRICT_ALL_TABLES)))
     {
-      my_error(ER_TOO_LONG_TABLE_COMMENT, MYF(0), table, tmp_len);
-      goto err;
+      my_error(ER_TOO_LONG_TABLE_COMMENT, MYF(0),
+               real_table_name, (uint) TABLE_COMMENT_MAXLEN);
+      my_free(screen_buff,MYF(0));
+      DBUG_RETURN(1);
     }
-    push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
-                        ER_TOO_LONG_TABLE_COMMENT,
-                        ER(ER_TOO_LONG_TABLE_COMMENT),
-                        table, tmp_len);
+    char warn_buff[MYSQL_ERRMSG_SIZE];
+    my_snprintf(warn_buff, sizeof(warn_buff), ER(ER_TOO_LONG_TABLE_COMMENT),
+                real_table_name, (uint) TABLE_COMMENT_MAXLEN);
+    /* do not push duplicate warnings */
+    if (!check_duplicate_warning(current_thd, warn_buff, strlen(warn_buff)))
+      push_warning(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
+                   ER_TOO_LONG_TABLE_COMMENT, warn_buff);
     create_info->comment.length= tmp_len;
   }
+  /*
+    If table comment is longer than TABLE_COMMENT_INLINE_MAXLEN bytes,
+    store the comment in an extra segment (up to TABLE_COMMENT_MAXLEN bytes).
+    Pre 6.0, the limit was 60 characters, with no extra segment-handling.
+  */
+  if (create_info->comment.length > TABLE_COMMENT_INLINE_MAXLEN)
+  {
+    forminfo[46]=255;
+    create_info->extra_size+= 2 + create_info->comment.length;
+  }
+  else{
+    strmake((char*) forminfo+47, create_info->comment.str ?
+            create_info->comment.str : "", create_info->comment.length);
+    forminfo[46]=(uchar) create_info->comment.length;
+  }
+
+  if ((file=create_frm(thd, file_name, db, table, reclength, fileinfo,
+		       create_info, keys, key_info)) < 0)
+  {
+    my_free(screen_buff, MYF(0));
+    DBUG_RETURN(1);
+  }
+
+  key_buff_length= uint4korr(fileinfo+47);
+  keybuff=(uchar*) my_malloc(key_buff_length, MYF(0));
+  key_info_length= pack_keys(keybuff, keys, key_info, data_offset);
+  (void) get_form_pos(file,fileinfo,&formnames);
+  if (!(filepos=make_new_entry(file,fileinfo,&formnames,"")))
+    goto err;
+  maxlength=(uint) next_io_size((ulong) (uint2korr(forminfo)+1000));
+  int2store(forminfo+2,maxlength);
+  int4store(fileinfo+10,(ulong) (filepos+maxlength));
+  fileinfo[26]= (uchar) test((create_info->max_rows == 1) &&
+			     (create_info->min_rows == 1) && (keys == 0));
+  int2store(fileinfo+28,key_info_length);
 
-  strmake((char*) forminfo+47, create_info->comment.str ?
-          create_info->comment.str : "", create_info->comment.length);
-  forminfo[46]=(uchar) create_info->comment.length;
 #ifdef WITH_PARTITION_STORAGE_ENGINE
   if (part_info)
   {
@@ -309,6 +333,15 @@ bool mysql_create_frm(THD *thd, const char *file_name,
         goto err;
     }
   }
+  if (forminfo[46] == (uchar)255)
+  {
+    uchar comment_length_buff[2];
+    int2store(comment_length_buff,create_info->comment.length);
+    if (mysql_file_write(file, comment_length_buff, 2, MYF(MY_NABP)) ||
+        mysql_file_write(file, (uchar*) create_info->comment.str,
+                         create_info->comment.length, MYF(MY_NABP)))
+      goto err;
+  }
 
   mysql_file_seek(file, filepos, MY_SEEK_SET, MYF(0));
   if (mysql_file_write(file, forminfo, 288, MYF_RW) ||
@@ -561,6 +594,16 @@ static uint pack_keys(uchar *keybuff, uint key_count, KEY *keyinfo,
     pos=tmp;
   }
   *(pos++)=0;
+  for (key=keyinfo,end=keyinfo+key_count ; key != end ; key++)
+  {
+    if (key->flags & HA_USES_COMMENT)
+    {
+      int2store(pos, key->comment.length);
+      uchar *tmp= (uchar*)strnmov((char*) pos+2,key->comment.str,
+                                  key->comment.length);
+      pos= tmp;
+    }
+  }
 
   if (key_count > 127 || key_parts > 127)
   {
@@ -614,19 +657,23 @@ static bool pack_header(uchar *forminfo, enum legacy_db_type table_type,
                                                      field->comment.str,
                                                      field->comment.str +
                                                      field->comment.length,
-                                                     255);
+                                                     COLUMN_COMMENT_MAXLEN);
     if (tmp_len < field->comment.length)
     {
       if ((current_thd->variables.sql_mode &
 	   (MODE_STRICT_TRANS_TABLES | MODE_STRICT_ALL_TABLES)))
       {
-        my_error(ER_TOO_LONG_FIELD_COMMENT, MYF(0), field->field_name, tmp_len);
+        my_error(ER_TOO_LONG_FIELD_COMMENT, MYF(0),
+                 field->field_name, (uint) COLUMN_COMMENT_MAXLEN);
 	DBUG_RETURN(1);
       }
-      push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
-                          ER_TOO_LONG_FIELD_COMMENT,
-                          ER(ER_TOO_LONG_FIELD_COMMENT),
-                          field->field_name, tmp_len);
+      char warn_buff[MYSQL_ERRMSG_SIZE];
+      my_snprintf(warn_buff, sizeof(warn_buff), ER(ER_TOO_LONG_FIELD_COMMENT),
+                  field->field_name, (uint) COLUMN_COMMENT_MAXLEN);
+      /* do not push duplicate warnings */
+      if (!check_duplicate_warning(current_thd, warn_buff, strlen(warn_buff)))
+        push_warning(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
+                     ER_TOO_LONG_FIELD_COMMENT, warn_buff);
       field->comment.length= tmp_len;
     }