NAME

       ALTER_SEQUENCE - change the definition of a sequence generator

SYNOPSIS

       ALTER SEQUENCE [ IF EXISTS ] name
           [ AS data_type ]
           [ 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 | CURRENT_ROLE | CURRENT_USER | SESSION_USER }
       ALTER SEQUENCE [ IF EXISTS ] name RENAME TO new_name
       ALTER SEQUENCE [ IF EXISTS ] name SET SCHEMA new_schema

DESCRIPTION

       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.

       data_type
           The optional clause AS data_type changes the data type of the sequence. Valid types
           are smallint, integer, and bigint.

           Changing the data type automatically changes the minimum and maximum values of the
           sequence if and only if the previous minimum and maximum values were the minimum or
           maximum value of the old data type (in other words, if the sequence had been created
           using NO MINVALUE or NO MAXVALUE, implicitly or explicitly). Otherwise, the minimum
           and maximum values are preserved, unless new values are given as part of the same
           command. If the minimum and maximum values do not fit into the new data type, an error
           will be generated.

       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 the minimum value of the
           data type 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 of the maximum value of the data type 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 similar 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.

           In contrast to a setval call, a RESTART operation on a sequence is transactional and
           blocks concurrent transactions from obtaining numbers from the same sequence. If
           that's not the desired mode of operation, setval should be used.

       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

       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.)

       ALTER SEQUENCE blocks concurrent nextval, currval, lastval, and setval calls.

       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 AS, START WITH, OWNED BY,
       OWNER TO, RENAME TO, and SET SCHEMA clauses, which are PostgreSQL extensions.

SEE ALSO

       CREATE SEQUENCE (CREATE_SEQUENCE(7)), DROP SEQUENCE (DROP_SEQUENCE(7))