Thread: How to migrate database from 10.1 to 9.1

Database is created in

    "PostgreSQL 10.1 on x86_64-pc-mingw64, compiled by gcc.exe (Rev5, Built 
by MSYS2 project) 4.9.2, 64-bit"

and contains tables with autogenerated primary keys like

    CREATE TABLE public.logifail
    (
      id integer NOT NULL DEFAULT nextval('logifail_id_seq'::regclass),
      ..
      CONSTRAINT logifail_pkey PRIMARY KEY (id),
      CONSTRAINT logifail_id_check CHECK (id > 0)
    )
    WITH (
      OIDS=FALSE
    );

if this database is restored to Postgres 9.1 from custom backup using


    pg_restore --role=$1_owner --no-owner --dbname=$1 --jobs=4 --verbose --username=postgres

automatic primary key generation stops working.

id column is restored without sequnece. Table becomes:

    CREATE TABLE logifail
    (
      id integer NOT NULL,
       ...
      CONSTRAINT logifail_pkey PRIMARY KEY (id),
      CONSTRAINT logifail_id_check CHECK (id > 0)
    )
    WITH (
      OIDS=FALSE
    );

How to fix this so that sequences are also restored ?
I tried to restore using both 10.1 and 9.1 pg_restore but autogenerated 
primary key columns are still lost.

Posted also in

https://stackoverflow.com/questions/50317935/how-to-ove-database-from-postgres-10-1-to-9-1

Andrus. 

"Andrus" <kobruleht2@hot.ee> writes:
> Database is created in
>     "PostgreSQL 10.1 on x86_64-pc-mingw64, compiled by gcc.exe (Rev5, Built 
> by MSYS2 project) 4.9.2, 64-bit"
> and contains tables with autogenerated primary keys like
> ...
> if this database is restored to Postgres 9.1 from custom backup using
> ...
> automatic primary key generation stops working.

This is a bit unfortunate, because it's not obvious to the naked eye that
a SERIAL column (I assume you actually defined the column as SERIAL?) is
using any new-in-v10 syntax.  But it is.  If you'd looked at the error
output you'd have noticed that the CREATE SEQUENCE command is getting a
syntax error:

psql:testv10.dump:58: ERROR:  syntax error at or near "AS"
LINE 2:     AS integer
            ^

You'd need to edit the dump output to remove the "AS integer" clause
in order to get this dump to load into a pre-v10 server.

Alternatively, I believe creating the column as BIGSERIAL would result in
dump files that would reload into older servers without adjustments.

            regards, tom lane