ALTER_SEQUENCE(7pg14)

💅 ALTER SEQUENCE — like, change the definition of a sequence generator (7pg14)

okay so bestie, welcome to ALTER_SEQUENCE, the page where we ✨edit✨ a sequence that already exists. it's the glow-up command. the makeover episode. no cap.

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🌸 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

like, four whole forms. pick your fighter 🫶

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🦋 DESCRIPTION 🦋

ALTER SEQUENCE changes the parameters of an existing sequence generator. that's the whole gig. and here's the part everyone loves: any parameters you don't specifically set in the ALTER SEQUENCE command just keep their prior settings. she's low-maintenance like that. 💖

so, the rules, because there are always rules:

• you must own the sequence to use ALTER SEQUENCE. it's her, you can't sit with her.
• 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.

the reason those restrictions exist? they enforce that altering the owner doesn't do anything you couldn't do by dropping and recreating the sequence. it's giving "no sneaky loopholes." 🎀 however — a superuser can alter ownership of any sequence anyway. main character energy, honestly. 👑

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🌈 PARAMETERS 🌈

• name — the name (optionally schema-qualified) of a sequence to be altered. who she is.
• IF EXISTS — do not throw an error if the sequence does not exist. a notice is issued in this case. so polite. 💅
• data_type — the optional clause AS data_type changes the data type of the sequence. valid types are smallint, integer, and bigint. that's it, that's the list, no extras.

and now the ✨fascinating✨ part: 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. and if the minimum and maximum values don't fit into the new data type? error. 💀

• 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. she remembers. 🧚
• 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. and listen — this has no effect on the current sequence value. it simply sets the value that future ALTER SEQUENCE RESTART commands will use. she's just taking notes for later. 📝
• 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.

and here's the difference that actually matters: 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. choose wisely bestie 😭

• 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. she does a little loop-de-loop 🌀
• 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. they go down together, iconic 💀 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". she's independent now 🦋
• 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.

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👑 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. so if your other session is acting like nothing happened — that's why. 🙈
• ALTER SEQUENCE does not affect the currval status for the sequence. (before PostgreSQL 8.3, it sometimes did. ancient lore.)
• ALTER SEQUENCE blocks concurrent nextval, currval, lastval, and setval calls. she's holding the door. 🚪
• 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. so like, technically yes, but also just use this one. 😌

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🍓 EXAMPLES 🍓

restart a sequence called serial, at 105:

ALTER SEQUENCE serial RESTART WITH 105;

that's it. that's the example. ate. 🔥

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⭐ COMPATIBILITY ⭐

ALTER SEQUENCE conforms to the SQL standard, except for the AS, START WITH, OWNED BY, OWNER TO, RENAME TO, and SET SCHEMA clauses — those are PostgreSQL extensions. our little bonus features 💜

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🌸 SEE ALSO 🌸

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

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okay go forth and alter your sequences bestie, you're gonna slay 💅✨

with love from PostgreSQL 14.24, dated 2026 — this has been ALTER SEQUENCE(7), mwah 🎀