[baseten-users] Problems with release 1.6

[Tuukka Norri]

Hi!

Jianhua Meng kirjoitti 1.4.2009 kello 18.58:
> We have been using a simple deployment process for installing  
> baseten based apps on desired target machines without trouble until  
> 1.6. The process consists of dumping the seed database which I use  
> for development and use the dump to load any desired target computer  
> for testing.  The problem appears to be that on any target computer  
> after the loading the database from the dump, the app gets stuck  
> from an exception caused by 'Entity ... doesn't have relationship  
> capability'.
Until version 1.6, we associated BaseTen's helper tables with user  
tables by their names. This was rather error-prone, though, as all  
special characters in relations' names weren't handled. Our  
implementation of determining whether a relation was BaseTen enabled  
or not, was also quite slow. To make the implementation simpler and  
more efficient, we decided to derive the helper tables' names from  
only the original relation's object identifier (oid).

The reason for the problem you're experiencing is that your relations  
get different oids each time they get created, whereas BaseTen's  
tables refer to the original oids. To solve it, you have two options,  
which are admittedly worse than just dumping the database contents and  
be done with it:

Firstly, don't include the BaseTen schema in your dump, and run  
BaseTen Assistant each time you restore the dump.

Secondly, we do have the low-level SQL functions at your disposal.  
Again, you shouldn't include the BaseTen schema in your dump. Here's a  
brief tutorial:
– Load your database contents using pg_restore or psql.
– Load the BaseTen schema into the database. (m4  
BaseTenModifications.sql.m4 > BaseTenModifications.sql; psql -f  
BaseTenModifications.sql your_database)
– Perform a query that will enable your tables. Here's one that works  
for multiple tables in the same schema:
SELECT baseten.enable (c.oid) FROM pg_class c INNER JOIN pg_namespace  
n ON c.relnamespace = n.oid WHERE n.nspname = 'your_schema' AND  
c.relname IN ('table_a', 'table_b', 'table_c');
– Finally perform a query like this:
SELECT baseten.refresh_caches ();

This does make restoring from backups lot less convenient. We'll see  
if we can do something to simplify things, like provide a command-line  
tool to do the tasks that BaseTen Assistant does.

> How does BaseTenAssistant tell if a table is enabled?
It looks if the table's oid is listed in baseten.enabled_relation.
-- 
Best regards,
Tuukka Norri
MK&C