目录

pg_sequence

一个存储有关序列信息的系统表

pg_sequence 是一个 系统目录 表，它存储有关序列的信息，并与序列在 pg_class 中的主条目相结合。

pg_sequence 在 PostgreSQL 10 中被添加。

备注

此更改将与序列关联的许多元数据从其关联的 关系 移动到此 系统目录 表中。这意味着 ALTER SEQUENCE 更新现在是完全事务性的。

系统目录 视图 pg_sequences 以更易于访问的方式显示序列信息，并且列名与之前在 序列关系 中存在的名称匹配。

有关此更改的更多详细信息，请参阅 PostgreSQL 10 发行说明。

按 PostgreSQL 版本定义

pg_sequence (PostgreSQL 19)

             Table "pg_catalog.pg_sequence"
    Column    |  Type   | Collation | Nullable | Default 
--------------+---------+-----------+----------+---------
 seqrelid     | oid     |           | not null | 
 seqtypid     | oid     |           | not null | 
 seqstart     | bigint  |           | not null | 
 seqincrement | bigint  |           | not null | 
 seqmax       | bigint  |           | not null | 
 seqmin       | bigint  |           | not null | 
 seqcache     | bigint  |           | not null | 
 seqcycle     | boolean |           | not null | 
Indexes:
    "pg_sequence_seqrelid_index" PRIMARY KEY, btree (seqrelid)

文档：pg_sequence

pg_sequence (PostgreSQL 18)

             Table "pg_catalog.pg_sequence"
    Column    |  Type   | Collation | Nullable | Default 
--------------+---------+-----------+----------+---------
 seqrelid     | oid     |           | not null | 
 seqtypid     | oid     |           | not null | 
 seqstart     | bigint  |           | not null | 
 seqincrement | bigint  |           | not null | 
 seqmax       | bigint  |           | not null | 
 seqmin       | bigint  |           | not null | 
 seqcache     | bigint  |           | not null | 
 seqcycle     | boolean |           | not null | 
Indexes:
    "pg_sequence_seqrelid_index" PRIMARY KEY, btree (seqrelid)

文档：pg_sequence

pg_sequence (PostgreSQL 17)

             Table "pg_catalog.pg_sequence"
    Column    |  Type   | Collation | Nullable | Default 
--------------+---------+-----------+----------+---------
 seqrelid     | oid     |           | not null | 
 seqtypid     | oid     |           | not null | 
 seqstart     | bigint  |           | not null | 
 seqincrement | bigint  |           | not null | 
 seqmax       | bigint  |           | not null | 
 seqmin       | bigint  |           | not null | 
 seqcache     | bigint  |           | not null | 
 seqcycle     | boolean |           | not null | 
Indexes:
    "pg_sequence_seqrelid_index" PRIMARY KEY, btree (seqrelid)

文档：pg_sequence

pg_sequence (PostgreSQL 16)

             Table "pg_catalog.pg_sequence"
    Column    |  Type   | Collation | Nullable | Default 
--------------+---------+-----------+----------+---------
 seqrelid     | oid     |           | not null | 
 seqtypid     | oid     |           | not null | 
 seqstart     | bigint  |           | not null | 
 seqincrement | bigint  |           | not null | 
 seqmax       | bigint  |           | not null | 
 seqmin       | bigint  |           | not null | 
 seqcache     | bigint  |           | not null | 
 seqcycle     | boolean |           | not null | 
Indexes:
    "pg_sequence_seqrelid_index" PRIMARY KEY, btree (seqrelid)

文档：pg_sequence

pg_sequence (PostgreSQL 15)

             Table "pg_catalog.pg_sequence"
    Column    |  Type   | Collation | Nullable | Default 
--------------+---------+-----------+----------+---------
 seqrelid     | oid     |           | not null | 
 seqtypid     | oid     |           | not null | 
 seqstart     | bigint  |           | not null | 
 seqincrement | bigint  |           | not null | 
 seqmax       | bigint  |           | not null | 
 seqmin       | bigint  |           | not null | 
 seqcache     | bigint  |           | not null | 
 seqcycle     | boolean |           | not null | 
Indexes:
    "pg_sequence_seqrelid_index" PRIMARY KEY, btree (seqrelid)

文档：pg_sequence

pg_sequence (PostgreSQL 14)

             Table "pg_catalog.pg_sequence"
    Column    |  Type   | Collation | Nullable | Default 
--------------+---------+-----------+----------+---------
 seqrelid     | oid     |           | not null | 
 seqtypid     | oid     |           | not null | 
 seqstart     | bigint  |           | not null | 
 seqincrement | bigint  |           | not null | 
 seqmax       | bigint  |           | not null | 
 seqmin       | bigint  |           | not null | 
 seqcache     | bigint  |           | not null | 
 seqcycle     | boolean |           | not null | 
Indexes:
    "pg_sequence_seqrelid_index" PRIMARY KEY, btree (seqrelid)

文档：pg_sequence

pg_sequence (PostgreSQL 13)

             Table "pg_catalog.pg_sequence"
    Column    |  Type   | Collation | Nullable | Default 
--------------+---------+-----------+----------+---------
 seqrelid     | oid     |           | not null | 
 seqtypid     | oid     |           | not null | 
 seqstart     | bigint  |           | not null | 
 seqincrement | bigint  |           | not null | 
 seqmax       | bigint  |           | not null | 
 seqmin       | bigint  |           | not null | 
 seqcache     | bigint  |           | not null | 
 seqcycle     | boolean |           | not null | 
Indexes:
    "pg_sequence_seqrelid_index" UNIQUE, btree (seqrelid)

文档：pg_sequence

pg_sequence (PostgreSQL 12)

             Table "pg_catalog.pg_sequence"
    Column    |  Type   | Collation | Nullable | Default 
--------------+---------+-----------+----------+---------
 seqrelid     | oid     |           | not null | 
 seqtypid     | oid     |           | not null | 
 seqstart     | bigint  |           | not null | 
 seqincrement | bigint  |           | not null | 
 seqmax       | bigint  |           | not null | 
 seqmin       | bigint  |           | not null | 
 seqcache     | bigint  |           | not null | 
 seqcycle     | boolean |           | not null | 
Indexes:
    "pg_sequence_seqrelid_index" UNIQUE, btree (seqrelid)

文档：pg_sequence

pg_sequence (PostgreSQL 11)

             Table "pg_catalog.pg_sequence"
    Column    |  Type   | Collation | Nullable | Default 
--------------+---------+-----------+----------+---------
 seqrelid     | oid     |           | not null | 
 seqtypid     | oid     |           | not null | 
 seqstart     | bigint  |           | not null | 
 seqincrement | bigint  |           | not null | 
 seqmax       | bigint  |           | not null | 
 seqmin       | bigint  |           | not null | 
 seqcache     | bigint  |           | not null | 
 seqcycle     | boolean |           | not null | 
Indexes:
    "pg_sequence_seqrelid_index" UNIQUE, btree (seqrelid)

文档：pg_sequence

pg_sequence (PostgreSQL 10)

             Table "pg_catalog.pg_sequence"
    Column    |  Type   | Collation | Nullable | Default 
--------------+---------+-----------+----------+---------
 seqrelid     | oid     |           | not null | 
 seqtypid     | oid     |           | not null | 
 seqstart     | bigint  |           | not null | 
 seqincrement | bigint  |           | not null | 
 seqmax       | bigint  |           | not null | 
 seqmin       | bigint  |           | not null | 
 seqcache     | bigint  |           | not null | 
 seqcycle     | boolean |           | not null | 
Indexes:
    "pg_sequence_seqrelid_index" UNIQUE, btree (seqrelid)

文档：pg_sequence

变更历史

自 PostgreSQL 10 添加以来，此表未被修改。

示例

在 PostgreSQL 9.6 及更早版本中，与序列相关的元数据存储在其关联的 关系 中，例如：

postgres=# CREATE SEQUENCE foo;
CREATE SEQUENCE

postgres=# SELECT * from public.foo;
-[ RECORD 1 ]-+--------------------
sequence_name | foo
last_value    | 1
start_value   | 1
increment_by  | 1
max_value     | 9223372036854775807
min_value     | 1
cache_value   | 1
log_cnt       | 0
is_cycled     | f
is_called     | f

从 PostgreSQL 10 开始，序列关系 只包含由 nextval() 函数修改的字段（last_value、log_cnt 和 is_called），例如：

postgres=# CREATE SEQUENCE foo;
CREATE SEQUENCE
postgres=# SELECT * from public.foo;
 last_value | log_cnt | is_called 
------------+---------+-----------
          1 |       0 | f
(1 row)

其余元数据存储在 pg_sequence 中，例如：

postgres=# SELECT * FROM pg_sequence WHERE seqrelid='foo'::REGCLASS;
-[ RECORD 1 ]+--------------------
seqrelid     | 16455
seqtypid     | 20
seqstart     | 1
seqincrement | 1
seqmax       | 9223372036854775807
seqmin       | 1
seqcache     | 1
seqcycle     | f

分类

DDL、序列、系统目录

另请参阅

pg_sequences、序列关系、pg_get_serial_sequence()

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