django-postgresql-fix-sequences

Fixes sequences in postgresql to help prevent the duplicate primary key errors.

The command needs to be run with all other connections to the database closed, so that there is no competition for the access to the sequences.

Examples:

python manage.py postgres_fix_sequences --auto
python manage.py postgres_fix_sequences --minvalue 1 --increment 2
python manage.py postgres_fix_sequences --tables=auth_user --auto

The fixes can be applied either to all tables that are part of a django project, or to specifically selected tables, in which case those tables do not have to be part of any django application.

Sequences can be fixed either automatically (where appropriate) or by manually setting the sequence parameters (supported values are minvalue and increment - as defined in CREATE SEQUENCE postgresql command).

Fix sequences automatically with the `--auto` flag

Sequences will be repaired automatically. Use this if you know that this is possible and safe, e.g. that the starting value and the step of the sequences are correct, but the current value may be off.

Note that either --auto or --min-value together with --increment must be given.

The command takes current value in the sequence currval() and the next value netxval() and determines step in the sequence.

Finds the highest id number (let's call it max_id) for the rows matching the given sequence, if id number is greater or equals to what is returned by the nextval() we need to set the current value with setval() to exactly what we found for max_id.

Specify minimum value and the increment for the sequence

If you cannot use the --auto method, then you have to specify --minvalue and --increment for the sequence manually. Both should be positive integers.

Specify tables manually with --tables option

For example, with:

python manage.py postgres_fix_sequences --tables=auth_user,auth_group

only tables auth_user and auth_group will be fixed.

Note that with the --tables table names do not have to be part of a django project.

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