concerning the duplicate key issue: by altering the rule into something like
CREATE or REPLACE RULE xowiki_page_r AS ON INSERT TO xowiki_pagei DO INSTEAD SELECT xowiki_pagei_f(new);
we have the effect, that an INSERT INTO xowiki_pagei (a dml statement) gets rewritten into a select statement. oacs complains, if one tries to run a select in a db_dml. The best trick to allow people (e.g. content::revision::new) still use the db_dml for the insert on VIEWi is to put an "begin; ... end;" around the sql-query in the db_dml implementation (the trick is due to Neophytos). Other suggestions?
The approach with the BEGIN .. END in dml statements (mentioned earlier) lead to other problems, so i changed for the time being the few instances, where sql statements inserts directly into the TABLENAMEi view, the command from db_dml to db_0or1row. This is necessary, since the rule processor of postgres rewrites now the insert rule into a select query calling the stored procedure. This happens only in three cases (acs-content-repository, dynamic-types, xowiki). There is as well an update to the TABLENAMEi view in form-procs of dynamic types, it might be necessary to check if this is ok.
The upgrade script contains the altered rule generator which generates now a rule + a stored procedure, which uses a variable to hold the temporary result. This should be faster than the old version based on cr_dummy, which essentially allows only one insert at a time.
The code was only tested with postgresql 8.0.
This patch is not intended for the general public,
but for developers for testing purposes. so, the
patch is against CVS head.
How to use this:
- make a dump of your database
- run the .sql file with
psql -U ... < cr-deadlock-duplicate-upgrade.sql
- cd packages; patch -p0 < cr-deadlock-duplicate.patch-HEAD
If we want to proceed with the patch, it will be necessary to provide a patch for content-types.sql as well.
I tried to modify the SQL script in order to apply the patch on PG 7.4.7 but since the "new" object of the rule can't be sent as a parameter the functions have to be generated with a parameter per column. This led to another problem because there are some revision views (e.g. as_sessionsi) with more than 32 attributes and 32 is the parameter limit for PG functions.
So, the chosen approach was to apply this change to every view with 32 or less attributes. Any advice will be really appreciated, though I think upgrading to PG8.1 would be the best to do :)