Meaning of _Index._Mod-sequence ?

andre42

Member
I just stumbled upon the field _Mod-sequence in the meta table _Index. Does anybody know what it is used for? The Progress Knowledge Base does not show any hits.
The usual value is ? but sometimes it contains 10 digit integers in our installation. Since I added some of the affected indices myself using a .df file I do not know where the values come from. I cannot write to this field either.
Here is a code example to show the values (only a few indices of our application show up).

Code:
FOR EACH _index
  WHERE _index._Mod-sequence <> ?
  NO-LOCK,
  FIRST _file
    WHERE RECID(_file) = _index._File-recid
    NO-LOCK:
    DISPLAY
       _file._file-name
       _index._Index-name
    STRING(_index._Mod-sequence, '9999999999':U).
END.
 

bulklodd

Member
though i'm not sure but it seems if the indexes have the same value in that field they were added in one transaction (a .df file is loaded in one physical transaction). moreover the less the value in the field the later an index was added. btw if the value is the unknown value it means the index related to the metatables not to the application's ones.

i don't think its value matters much to an application, so there's no need to worry about it.

hth
 

andre42

Member
though i'm not sure but it seems if the indexes have the same value in that field they were added in one transaction (a .df file is loaded in one physical transaction). moreover the less the value in the field the later an index was added. btw if the value is the unknown value it means the index related to the metatables not to the application's ones.

i don't think its value matters much to an application, so there's no need to worry about it.

hth
That makes sense. The reason I noticed this is that when I inspect indices with on of our development tools I get messages like
** Value 1179821244 cannot be displayed using >>>>>>9. (74)
because the format of _index._Mod-sequence only has 9 digits but the values are 10 digits. I will suggest to enhance the regarding tool if this has not happened yet.
Like I said most of the application's indices have an unknown value in this field. The reason is probably that the database was converted from Progress 9 which does not have this field yet.

Thanks!
 
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