Thomas thanks for your answers and excuse me for the subject.

Thomas Mueller escribió:
> Please use another subject, don't just reply to the "New version
> available" subject.
>
>   
>> (1) It's planned a "SELECT INTO new_table" or "CREATE TABLE as
>> ( select_resultset )" or materialized views aka DB2 ?
>>     
>
> CREATE TABLE AS SELECT is already supported.
> Materialized views are not supported, those are tricky to implement.
>   
Perfect !
>> (2) If I have many LINKED TABLES defined to the same database, with
>> the same driver and with the same user ,
>>    same connection settings (isolation level, autocommit, etc.),
>>    can I be sure that only one connection will be done for all this
>> linked tables ?
>>    Can this mono/multi connection behavior controlled in some way ?
>>     
>
> Yes, this is already supported. See the changelogs of version 1.0.79
> (2008-09-26)
>
>   
>>    can I be sure that only one copy of JDBC driver will be loaded ?
>>     
>
> I'm not sure if this question is related to LINKED TABLES.
>   
Yes it's, my question is if there are some specialized ClassLoader for
isolation of  connection/JdbcDriver in a per table basis (like WebSphere
does for  conectors).
>> (3) From (2) ,  When and How long will be connected the other
>> datasource ?
>> It's connected at startup or lazy until this linked table is used in
>> some query ?
>> Can this behavior be controlled in some way ?
>>     
>
> When the database is opened, but if the linked database is not
> accessible at that time then later when accessing the table. Why is
> that important for you?
>   
I'm trying to use H2 as from-end database cache/copy of a collected data
model from various big and distributed back-end database servers.
Cached/replicated data to H2 is a sub-set of data in other dbms, that
have limitations in how many simultaneous connections can support and
convenience time windows (or events) for access their information.

An basic aim is to liberate these servers as much as posible of workload
delegated to H2 and to generate some redundancy for HA.
So, it's really important for us to have precise control of when and how
the backend is accesed.
In my opinion, it would be convenient for both H2 and backend dbm if the
connection is established only at the time it is used and closed after
an configurable period of time, freeing resources from both dbm.


Regards,
Dario

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