Re: [ADMIN] Cannot retrieve images inserted through VB and odbc, after a table reorganization. - Mailing list pgsql-general

From David G Johnston
Subject Re: [ADMIN] Cannot retrieve images inserted through VB and odbc, after a table reorganization.
Date
Msg-id 1409840147898-5817761.post@n5.nabble.com
Whole thread Raw
In response to Re: Re: [ADMIN] Cannot retrieve images inserted through VB and odbc, after a table reorganization.  (Adrian Klaver <adrian.klaver@aklaver.com>)
Responses Re: Re: [ADMIN] Cannot retrieve images inserted through VB and odbc, after a table reorganization.
List pgsql-general
Adrian Klaver-4 wrote
> On 09/04/2014 05:56 AM, Alanoly Andrews wrote:
>> Hi Adrian,
>>
>> Thanks for that explanation of how the "relfilenode" changes after a
>> table reorganization. It is not surprising that this happens because the
>> table rows are being physically moved from one location to another. But
>> such changes at the backend should be transparent to the end user. The VB
>> code at the client side runs a simple sql like "select image from
>> image_table where image_key=somevalue". There is no reference to
>> postgres-specific internal variables like "oid" and "relfilenode". I do
>> not know the inner workings of the postgres odbc driver; but I would be
>> surprised if it works at the granularity of "oid" and "relfilenode" and
>> that it would store the actual physical values of relfilenode (which
>> would keep changing after every table reload, reorg etc.).
>
> In addition to what David mentioned, some more detail on what you are
> calling a 'large object'.  In Postgres there is not really a 'large
> object' type(though I am guilty of saying there is), instead there is a
> way of working with large objects outside of the bytea type. Now in the
> ODBC FAQ there is a recipe for creating a 'lo' type:
>
> http://psqlodbc.projects.pgfoundry.org/faq.html#4.4
>
> Is this what you are using?
>
> If not how are you working with the large objects?
>
> Also given that you are working with the Postgres ODBC driver, you might
> want to break the cross post rule and ask this question on the psql-odbc
> list:
>
> http://www.postgresql.org/list/pgsql-odbc/
>
> In any case your ODBC settings would be helpful.

I suspect the OP is referring to the contrib module/extension:

http://www.postgresql.org/docs/9.1/interactive/lo.html

David J.



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