Ubuntu Manpage: ALTER_SEQUENCE - change the definition of a sequence generator

Provided by: postgres-xc-client_1.1-2ubuntu2_amd64

NAME

       ALTER_SEQUENCE - change the definition of a sequence generator

SYNOPSIS

       ALTER SEQUENCE [ IF EXISTS ] name [ INCREMENT [ BY ] increment ]
           [ MINVALUE minvalue | NO MINVALUE ] [ MAXVALUE maxvalue | NO MAXVALUE ]
           [ START [ WITH ] start ]
           [ RESTART [ [ WITH ] restart ] ]
           [ CACHE cache ] [ [ NO ] CYCLE ]
           [ OWNED BY { table_name.column_name | NONE } ]
       ALTER SEQUENCE [ IF EXISTS ] name OWNER TO new_owner
       ALTER SEQUENCE [ IF EXISTS ] name RENAME TO new_name
       ALTER SEQUENCE [ IF EXISTS ] name SET SCHEMA new_schema

DESCRIPTION

           Note

           The following description applies both to Postgres-XC and PostgreSQL if not described explicitly.

       ALTER SEQUENCE changes the parameters of an existing sequence generator. Any parameters not specifically
       set in the ALTER SEQUENCE command retain their prior settings.

       You must own the sequence to use ALTER SEQUENCE. To change a sequence's schema, you must also have CREATE
       privilege on the new schema. To alter the owner, you must also be a direct or indirect member of the new
       owning role, and that role must have CREATE privilege on the sequence's schema. (These restrictions
       enforce that altering the owner doesn't do anything you couldn't do by dropping and recreating the
       sequence. However, a superuser can alter ownership of any sequence anyway.)

PARAMETERS

name
The name (optionally schema-qualified) of a sequence to be altered.

IF EXISTS
Do not throw an error if the sequence does not exist. A notice is issued in this case.

increment
The clause INCREMENT BY increment is optional. A positive value will make an ascending sequence, a
negative one a descending sequence. If unspecified, the old increment value will be maintained.

minvalue, NO MINVALUE
The optional clause MINVALUE minvalue determines the minimum value a sequence can generate. If NO
MINVALUE is specified, the defaults of 1 and -263-1 for ascending and descending sequences,
respectively, will be used. If neither option is specified, the current minimum value will be
maintained.

maxvalue, NO MAXVALUE
The optional clause MAXVALUE maxvalue determines the maximum value for the sequence. If NO MAXVALUE
is specified, the defaults are 263-1 and -1 for ascending and descending sequences, respectively,
will be used. If neither option is specified, the current maximum value will be maintained.

start
The optional clause START WITH start changes the recorded start value of the sequence. This has no
effect on the current sequence value; it simply sets the value that future ALTER SEQUENCE RESTART
commands will use.

restart
The optional clause RESTART [ WITH restart ] changes the current value of the sequence. This is
equivalent to calling the setval function with is_called = false: the specified value will be
returned by the next call of nextval. Writing RESTART with no restart value is equivalent to
supplying the start value that was recorded by CREATE SEQUENCE or last set by ALTER SEQUENCE START
WITH.

cache
The clause CACHE cache enables sequence numbers to be preallocated and stored in memory for faster
access. The minimum value is 1 (only one value can be generated at a time, i.e., no cache). If
unspecified, the old cache value will be maintained.

CYCLE
The optional CYCLE key word can be used to enable the sequence to wrap around when the maxvalue or
minvalue has been reached by an ascending or descending sequence respectively. If the limit is
reached, the next number generated will be the minvalue or maxvalue, respectively.

NO CYCLE
If the optional NO CYCLE key word is specified, any calls to nextval after the sequence has reached
its maximum value will return an error. If neither CYCLE or NO CYCLE are specified, the old cycle
behavior will be maintained.

OWNED BY table_name.column_name, OWNED BY NONE
The OWNED BY option causes the sequence to be associated with a specific table column, such that if
that column (or its whole table) is dropped, the sequence will be automatically dropped as well. If
specified, this association replaces any previously specified association for the sequence. The
specified table must have the same owner and be in the same schema as the sequence. Specifying OWNED
BY NONE removes any existing association, making the sequence “free-standing”.

new_owner
The user name of the new owner of the sequence.

new_name
The new name for the sequence.

new_schema
The new schema for the sequence.

NOTES

       To avoid blocking of concurrent transactions that obtain numbers from the same sequence, ALTER SEQUENCE's
       effects on the sequence generation parameters are never rolled back; those changes take effect
       immediately and are not reversible. However, the OWNED BY, OWNER TO, RENAME TO, and SET SCHEMA clauses
       cause ordinary catalog updates that can be rolled back.

       ALTER SEQUENCE will not immediately affect nextval results in backends, other than the current one, that
       have preallocated (cached) sequence values. They will use up all cached values prior to noticing the
       changed sequence generation parameters. The current backend will be affected immediately.

       ALTER SEQUENCE does not affect the currval status for the sequence. (Before PostgreSQL 8.3, it sometimes
       did.)

       For historical reasons, ALTER TABLE can be used with sequences too; but the only variants of ALTER TABLE
       that are allowed with sequences are equivalent to the forms shown above.

EXAMPLES

       Restart a sequence called serial, at 105:

           ALTER SEQUENCE serial RESTART WITH 105;

COMPATIBILITY

       ALTER SEQUENCE conforms to the SQL standard, except for the START WITH, OWNED BY, OWNER TO, RENAME TO,
       and SET SCHEMA clauses, which are PostgreSQL extensions.