Hi,

For our application, we are currently modeling a data object [1] , in
CDO this translates to an object which in an MySQL Store for CDO looks
like [2].

As we are talking about 100's of millions of these volatile objects, we
are considering modeling this differently (Size of the DB is the reason,
see the SQL table in [2]).

BTW the operations we perform is
- Writing (single values).
- Reading, with a select on the value Timestamp. (Currently with CDO
SQL query handler).

I am considering two options.

1) Using a custom data type. I am not sure what this means for CDO. I
pressume, the Value object will still be an object with lifecycle etc..

2) using a specific file based store, whereby the 'Value' will be
referred to by a CDO External reference, letting a specific EMF Resource
implementation retrieving the objects from a file.


From the community, I would like to ask if someone has experience with
1) and 2) and what should be considered. For 2) for example I can
imagine, that the query facility would be something to build from
scratch and/or would perhaps require some indexing.

Any advise on this?
Thank You,
Christophe

[1] In .xsd it looks like this:

<!--_____________________________ -->
<!--| VALUE | -->
<!--|___________________________| -->
<xs:complexType name="Value">
<xs:attribute name="Value" type="xs:double"/>
<xs:attribute name="TimeStamp" type="xs:dateTime"/>
</xs:complexType>

[2] In CDO--> MySQL

mysql> describe generics_Value;
+---------------+------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+---------------+------------+------+-----+---------+-------+
| cdo_id | bigint(20) | NO | PRI | NULL | |
| cdo_version | int(11) | NO | PRI | NULL | |
| cdo_created | bigint(20) | NO | | NULL | |
| cdo_revised | bigint(20) | NO | | NULL | |
| cdo_resource | bigint(20) | NO | | NULL | |
| cdo_container | bigint(20) | NO | | NULL | |
| cdo_feature | int(11) | NO | | NULL | |
| timeStamp0 | longtext | YES | | NULL | |
| value | longtext | YES | | NULL | |
| cdo_set_value | tinyint(1) | YES | | NULL | |
+---------------+------------+------+-----+---------+-------+