Re: A question about sequences and backup/restore cycles

On 10/22/19 10:48 AM, stan wrote:
Please reply to list also:
Ccing list.


> 
> Sorry if my description was not clear.
> 
> No, we  do not mix test, and production data. Let me try to clarify the
> question. Looking at a pg_dump, I see the following:
> 
> 
> CREATE SEQUENCE public.customer_key_serial
>      START WITH 1
>     INCREMENT BY 1
>     NO MINVALUE
>     NO MAXVALUE
>     CACHE 1;
> 
> 
> Yet, in the same pg_dump file I have:
> 
> 
> 
> 
> COPY public.customer (customer_key, cust_no, name, c_type, location,
> bill_address_1, bill_address_2, bill_city, bill_state, bill_zip,
> bill_country, bill_attention, bill_addressee, ship_address_1,
> ship_address_2, ship_addressee, ship_attention, ship_city, ship_state,
> ship_zip, office_phone_area_code, office_phone_exchange,
> office_phone_number, office_phone_extension, cell_phone_area_code,
> cell_phone_exchange, cell_phone_number, ship_phone_area_code,
> ship_phone_exchange, ship_phone_number, ship_phone_extension,
> fax_phone_area_code, fax_phone_exchange, fax_phone_number, status, modtime)
> FROM stdin;
> 1       12      Made Up Inc.    INDUSTRIAL_CONVEYOR     \N      101 Nowhere
> Ave.        \N      LaGrange        GA      00000   \N      \N      \N
> \N      \N      \N      \N      \N      \N      00000   \N      \N      \N
>     \N      \N      \N      \N      \N      \N      \N      \N      \N
>     \N      \N      ACTIVE  2019-09-30 23:55:04.594203+00
>     2       5       Jimmys Favorite Customer.       PLASTICS        \N
>     56 Somewhere St.        \N      No Such City    SC      00000   \N
>     \N      \N      \N      \N      \N      \N      \N      \N      00000
>     \N      \N      \N      \N      \N      \N      \N      \N      \N
>     \N      \N      \N      \N      \N      ACTIVE  2019-09-30
>     23:55:04.636827+00
> 
> So it appears to me the customer table is going to get (correctly) populated
> with the originally generated keys, yet the sequence will want to return a 1
> the next time it is called, when a new customer gets inserted.
> 
> Am I missing something here?
> 

Yes something like this, in dump file, for non-serial sequence:

CREATE SEQUENCE public.plant1_p_item_no_seq
     START WITH 1
     INCREMENT BY 1
     NO MINVALUE
     NO MAXVALUE
     CACHE 1;

SELECT pg_catalog.setval('public.plant1_p_item_no_seq', 5509, true);

or for serial sequence:

CREATE SEQUENCE public.avail_headers_line_id_seq
     AS integer
     START WITH 1
     INCREMENT BY 1
     NO MINVALUE
     NO MAXVALUE
     CACHE 1;

ALTER TABLE ONLY public.avail_headers ALTER COLUMN line_id SET DEFAULT 
nextval('public.avail_headers_line_id_seq'::regclass);


SELECT pg_catalog.setval('public.avail_headers_line_id_seq', 53, true);

If you want to see how things are run on a higher level do something like:

pg_dump -Fc -d some_db -f db.out

pg_restore -l db_out > db_toc.txt

-l on pg_restore creates a TOC(table of contents) showing the ordering 
of the schema recreation.


-- 
Adrian Klaver
adrian.klaver@aklaver.com