Due to the way Slony disables triggers in combination how foreign keys 
are implemented in PostgreSQL, you would have to do that drop table 
through slonik's EXECUTE SCRIPT functionality as well.


Jan


On 7/20/2005 3:24 PM, Ian Burrell wrote:

> We ran into some weirdness applying a schema change to the slave
> databases.  The change was to DROP a table which was not replicated
> but had a foreign key referenceto a table which is replicated.  It
> worked fine on the master database but broke on the slave databases.
> 
> vodlive_slave1=# drop table mc_today_xtns
> ERROR:  "pk_mc_subscribers" is an index
> 
> My suspicion was that it was related to the foreign key from
> mc_today_xtns to mc_subscribers.
> 
>     "fk_mc_today_xtns_mc_subscriber" FOREIGN KEY (mc_subscriber_no)
> REFERENCES mc_subscribers(mc_subscriber_no) DEFERRABLE
> 
> Dropping the foreign key failed:
> 
> vodlive_slave1=# alter table mc_today_xtns drop constraint
> fk_mc_today_xtns_mc_subscriber ;
> ERROR:  "pk_mc_subscribers" is an index
> 
> I think what is happening is that slony has removed the triggers for
> the foreign key on mc_subscribers:
> 
> voddev_slave1=# select relname, pg_trigger.* from pg_trigger join
> pg_class on tgrelid = pg_class.oid where relname = 'mc_subscribers' ;
>     relname     | tgrelid  |         tgname          |  tgfoid  |
> tgtype | tgenabled | tgisconstraint | tgconstrname | tgconstrrelid |
> tgdeferrable | tginitdeferred | tgnargs | tgattr |    tgargs
> ----------------+----------+-------------------------+----------+--------+-----------+----------------+--------------+---------------+--------------+----------------+---------+--------+---------------
>  mc_subscribers | 28724489 | _vodslony_denyaccess_65 | 45139590 | 31 |
> t         | f              |              |            0 | f      | f 
>             |       1 |        | _vodslony\000
> 
> On the master, there are triggers for all of the foreign key
> constraints which point to mc_subscribers.
> 
> I would think removing the foreign key triggers on the slaves is the
> wrong thing to do.  Should we remove the foreign keys on the slave
> databases?
> 
>  - Ian
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> Slony1-general at gborg.postgresql.org
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