Try the following queries. It will give you two .sql files (create_fkeys.sql & drop_fkeys.sql).
First review them to make sure they look ok.
Then execute the drop_fkeys.sql
ie: \i drop_fkeys.sql
Do your deletes, then rebuild your fk's with
\i create_fkeys.sql
Good luck.
========================================================== -- CREATE STATEMENT FOR ALL FK's
\o create_fkeys.sql
SELECT E'\\timing';
SELECT 'ALTER TABLE ' || n.nspname || '.' || '"' || t.relname || '"' || ' ADD CONSTRAINT ' || '"' || c.conname || '"' || ' ' || pg_get_constraintdef( c.oid) || ';' FROM pg_class t JOIN pg_constraint c ON ( c.conrelid = t.OID AND c.contype = 'f') JOIN pg_namespace n ON (n.oid = t.relnamespace) JOIN pg_class f ON (f.oid = c.confrelid) WHERE c.contype = 'f' AND t.relkind = 'r' AND t.relname NOT LIKE 'pg_%' AND t.relname NOT LIKE 'sql_%' ORDER BY n.nspname, t.relname;
-- DROP FK's
\o drop_fkeys.sql
SELECT E'\\timing';
SELECT 'ALTER TABLE ' || n.nspname || '.' || '"' || t.relname || '"' || ' DROP CONSTRAINT ' || '"' || c.conname || '"' || ' CASCADE;' FROM pg_class t JOIN pg_constraint c ON ( c.conrelid = t.OID AND c.contype = 'f') JOIN pg_namespace n ON (n.oid = t.relnamespace) JOIN pg_class f ON (f.oid = c.confrelid) WHERE c.contype = 'f' AND t.relkind = 'r' AND t.relname NOT LIKE 'pg_%' AND t.relname NOT LIKE 'sql_%' ORDER BY 1;
On Thu, Nov 20, 2014 at 5:13 PM, Jonathan Vanasco <postgres@2xlp.com> wrote:
I have a core table with tens-of-millions of rows, and need to delete about a million records.
There are 21 foreign key checks against this table. Based on the current performance, it would take a few days to make my deletions.
None of the constraints were defined as `DEFERRABLE INITIALLY IMMEDIATE', so I'm out of luck on deferring them.
Dropping/redefining constraints looks to be an ordeal -- and something I'm scared to make a mistake on.
i looked into disabling triggers on a table, but I couldn't find any info on how to trigger at the end of the transaction so I can ensure integrity.
does anyone have suggestions on things that might work?