我遇到了一个问题,我的主键序列与我的表行不同步。

也就是说,当我插入一个新行时,我得到一个重复的键错误,因为在串行数据类型中隐含的序列返回一个已经存在的数字。

这似乎是由于导入/恢复没有正确地维护序列造成的。


当前回答

重置所有序列,除了每个表的主键是“id”外,对名称没有任何假设:

CREATE OR REPLACE FUNCTION "reset_sequence" (tablename text, columnname text)
RETURNS "pg_catalog"."void" AS
$body$
DECLARE
BEGIN
    EXECUTE 'SELECT setval( pg_get_serial_sequence(''' || tablename || ''', ''' || columnname || '''),
    (SELECT COALESCE(MAX(id)+1,1) FROM ' || tablename || '), false)';
END;
$body$  LANGUAGE 'plpgsql';

select table_name || '_' || column_name || '_seq', reset_sequence(table_name, column_name) from information_schema.columns where column_default like 'nextval%';

其他回答

试着重建索引。

更新:正如评论中指出的,这是对最初问题的回答。

Pg_get_serial_sequence可以用来避免任何关于序列名称的错误假设。这将在一个镜头中重置序列:

SELECT pg_catalog.setval(pg_get_serial_sequence('table_name', 'id'), (SELECT MAX(id) FROM table_name)+1);

或者更简洁地说:

SELECT pg_catalog.setval(pg_get_serial_sequence('table_name', 'id'), MAX(id)) FROM table_name;

然而,这个表单不能正确地处理空表,因为max(id)是空的,你也不能设置val 0,因为它超出了序列的范围。一种解决方法是使用ALTER SEQUENCE语法。

ALTER SEQUENCE table_name_id_seq RESTART WITH 1;
ALTER SEQUENCE table_name_id_seq RESTART; -- 8.4 or higher

但是ALTER SEQUENCE的用途有限,因为序列名和重启值不能是表达式。

似乎最好的通用解决方案是调用setval,将false作为第三个参数,允许我们指定“下一个要使用的值”:

SELECT setval(pg_get_serial_sequence('t1', 'id'), coalesce(max(id),0) + 1, false) FROM t1;

这符合我所有的条件:

避免硬编码实际的序列名 正确处理空表 使用现有数据处理表,并且不会留下 序列中的漏洞

最后,请注意,pg_get_serial_sequence仅在序列属于列时才有效。如果将递增列定义为串行类型,则会出现这种情况,但是如果手动添加序列,则需要确保ALTER sequence。“OWNED BY”也被执行。

例如,如果使用serial type来创建表,这应该都可以工作:

CREATE TABLE t1 (
  id serial,
  name varchar(20)
);

SELECT pg_get_serial_sequence('t1', 'id'); -- returns 't1_id_seq'

-- reset the sequence, regardless whether table has rows or not:
SELECT setval(pg_get_serial_sequence('t1', 'id'), coalesce(max(id),0) + 1, false) FROM t1;

但如果手动添加序列:

CREATE TABLE t2 (
  id integer NOT NULL,
  name varchar(20)
);

CREATE SEQUENCE t2_custom_id_seq
    START WITH 1
    INCREMENT BY 1
    NO MINVALUE
    NO MAXVALUE
    CACHE 1;

ALTER TABLE t2 ALTER COLUMN id SET DEFAULT nextval('t2_custom_id_seq'::regclass);

ALTER SEQUENCE t2_custom_id_seq OWNED BY t2.id; -- required for pg_get_serial_sequence

SELECT pg_get_serial_sequence('t2', 'id'); -- returns 't2_custom_id_seq'

-- reset the sequence, regardless whether table has rows or not:
SELECT setval(pg_get_serial_sequence('t2', 'id'), coalesce(max(id),0) + 1, false) FROM t1;

之前我还没有尝试过代码:在下面我张贴 Klaus和user457226解决方案的sql代码版本 它在我的电脑上运行(Postgres 8.3),只做了一些小调整 克劳斯的版本和我的user457226版本。

克劳斯解决方案:

drop function IF EXISTS rebuilt_sequences() RESTRICT;
CREATE OR REPLACE FUNCTION  rebuilt_sequences() RETURNS integer as
$body$
  DECLARE sequencedefs RECORD; c integer ;
  BEGIN
    FOR sequencedefs IN Select
      constraint_column_usage.table_name as tablename,
      constraint_column_usage.table_name as tablename, 
      constraint_column_usage.column_name as columnname,
      replace(replace(columns.column_default,'''::regclass)',''),'nextval(''','') as sequencename
      from information_schema.constraint_column_usage, information_schema.columns
      where constraint_column_usage.table_schema ='public' AND 
      columns.table_schema = 'public' AND columns.table_name=constraint_column_usage.table_name
      AND constraint_column_usage.column_name = columns.column_name
      AND columns.column_default is not null
   LOOP    
      EXECUTE 'select max('||sequencedefs.columnname||') from ' || sequencedefs.tablename INTO c;
      IF c is null THEN c = 0; END IF;
      IF c is not null THEN c = c+ 1; END IF;
      EXECUTE 'alter sequence ' || sequencedefs.sequencename ||' restart  with ' || c;
   END LOOP;

   RETURN 1; END;
$body$ LANGUAGE plpgsql;

select rebuilt_sequences();

User457226解决方案:

--drop function IF EXISTS reset_sequence (text,text) RESTRICT;
CREATE OR REPLACE FUNCTION "reset_sequence" (tablename text,columnname text) RETURNS bigint --"pg_catalog"."void"
AS
$body$
  DECLARE seqname character varying;
          c integer;
  BEGIN
    select tablename || '_' || columnname || '_seq' into seqname;
    EXECUTE 'SELECT max("' || columnname || '") FROM "' || tablename || '"' into c;
    if c is null then c = 0; end if;
    c = c+1; --because of substitution of setval with "alter sequence"
    --EXECUTE 'SELECT setval( "' || seqname || '", ' || cast(c as character varying) || ', false)'; DOES NOT WORK!!!
    EXECUTE 'alter sequence ' || seqname ||' restart with ' || cast(c as character varying);
    RETURN nextval(seqname)-1;
  END;
$body$ LANGUAGE 'plpgsql';

select sequence_name, PG_CLASS.relname, PG_ATTRIBUTE.attname,
       reset_sequence(PG_CLASS.relname,PG_ATTRIBUTE.attname)
from PG_CLASS
join PG_ATTRIBUTE on PG_ATTRIBUTE.attrelid = PG_CLASS.oid
join information_schema.sequences
     on information_schema.sequences.sequence_name = PG_CLASS.relname || '_' || PG_ATTRIBUTE.attname || '_seq'
where sequence_schema='public';

我建议在postgres wiki上找到这个解决方案。它更新表的所有序列。

SELECT 'SELECT SETVAL(' ||
       quote_literal(quote_ident(PGT.schemaname) || '.' || quote_ident(S.relname)) ||
       ', COALESCE(MAX(' ||quote_ident(C.attname)|| '), 1) ) FROM ' ||
       quote_ident(PGT.schemaname)|| '.'||quote_ident(T.relname)|| ';'
FROM pg_class AS S,
     pg_depend AS D,
     pg_class AS T,
     pg_attribute AS C,
     pg_tables AS PGT
WHERE S.relkind = 'S'
    AND S.oid = D.objid
    AND D.refobjid = T.oid
    AND D.refobjid = C.attrelid
    AND D.refobjsubid = C.attnum
    AND T.relname = PGT.tablename
ORDER BY S.relname;

如何使用(来自postgres wiki):

保存到一个文件,输入'reset。sql' 运行该文件并以不包括通常头的方式保存其输出,然后运行该输出。例子:

例子:

psql -Atq -f reset.sql -o temp
psql -f temp
rm temp

原文(也修复了序列所有权)在这里

重置所有序列,除了每个表的主键是“id”外,对名称没有任何假设:

CREATE OR REPLACE FUNCTION "reset_sequence" (tablename text, columnname text)
RETURNS "pg_catalog"."void" AS
$body$
DECLARE
BEGIN
    EXECUTE 'SELECT setval( pg_get_serial_sequence(''' || tablename || ''', ''' || columnname || '''),
    (SELECT COALESCE(MAX(id)+1,1) FROM ' || tablename || '), false)';
END;
$body$  LANGUAGE 'plpgsql';

select table_name || '_' || column_name || '_seq', reset_sequence(table_name, column_name) from information_schema.columns where column_default like 'nextval%';