ALTER SEQUENCE SQL - Language Statements ALTER SEQUENCE alter the definition of a sequence generator 1999-07-20 ALTER SEQUENCE seqname [ INCREMENT [ BY ] increment ] [ MINVALUE minvalue | NO MINVALUE ] [ MAXVALUE maxvalue | NO MAXVALUE ] [ RESTART [ WITH ] start ] [ CACHE cache ] [ [ NO ] CYCLE ] 1998-09-11 seqname The name (optionally schema-qualified) of a sequence to be altered. increment The INCREMENT BY increment clause 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 -2^63-1 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 2^63-1 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 RESTART WITH start clause enables the sequence to re-begin anywhere. cache The CACHE cache option 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 keyword may 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 keyword 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 behaviour will be maintained. 1998-09-11 ALTER SEQUENCE Message returned if the command is successful. ERROR: AlterSequence: MINVALUE (start) can't be >= MAXVALUE (max) If the specified starting value is out of range. ERROR: AlterSequence: START value (start) can't be < MINVALUE (min) If the specified starting value is out of range. ERROR: AlterSequence: MINVALUE (min) can't be >= MAXVALUE (max) If the minimum and maximum values are inconsistent. See for limitations, and uses of sequences. Restart a sequence called serial, at 105: ALTER SEQUENCE serial RESTART WITH 105; To avoid blocking of concurrent transactions that obtain numbers from the same sequence, a nextval operation is never rolled back; that is, once a value has been fetched it is considered used, even if the transaction that did the nextval later aborts. This means that aborted transactions may leave unused "holes" in the sequence of assigned values. setval operations are never rolled back, either. ALTER SEQUENCE will not immediately affect backends, other than the current one, which have cached sequence values. They must use up all cached values prior to noticing the changed sequence parameters. The current backend will be immediatly affected. 2003-03-02 ALTER SEQUENCE is a PostgreSQL language extension. There is no ALTER SEQUENCE statement in SQL99.