Postgres manually alter sequence

Question

I'm trying to set a sequence to a specific value.

SELECT setval('payments_id_seq'), 21, true 

This gives an error:

ERROR: function setval(unknown) does not exist

Using ALTER SEQUENCE doesn't seem to work either?

ALTER SEQUENCE payments_id_seq LASTVALUE 22 

How can this be done?

Ref: https://www.postgresql.org/docs/current/static/functions-sequence.html

Answer 1

The parentheses are misplaced:

SELECT setval('payments_id_seq', 21, true);  # next value will be 22 

Otherwise you're calling setval with a single argument, while it requires two or three.

This is the same as SELECT setval('payments_id_seq', 21)

Answer 2

This syntax isn't valid in any version of PostgreSQL:

ALTER SEQUENCE payments_id_seq LASTVALUE 22

This would work:

ALTER SEQUENCE payments_id_seq RESTART WITH 22; 

And is equivalent to:

SELECT setval('payments_id_seq', 22, FALSE); 

More in the current manual for ALTER SEQUENCE and sequence functions.

Note that setval() expects either (regclass, bigint) or (regclass, bigint, boolean). In the above example I am providing untyped literals. That works too. But if you feed typed variables to the function you may need explicit type casts to satisfy function type resolution. Like:

SELECT setval(my_text_variable::regclass, my_other_variable::bigint, FALSE); 

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For repeated operations you might be interested in:

ALTER SEQUENCE payments_id_seq START WITH 22; -- set default ALTER SEQUENCE payments_id_seq RESTART;       -- without value 

START [WITH] stores a default RESTART number, which is used for subsequent RESTART calls without value. You need Postgres 8.4 or later for the last part.