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。
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%';