pgsql批量修改sequences的start方式_PostgreSQL

pgsql批量修改sequences的start方式

2021-02-27 18:31_rtf PostgreSQL

这篇文章主要介绍了pgsql批量修改sequences的start方式，具有很好的参考价值，希望对大家有所帮助。一起跟随小编过来看看吧

修改为指定值

									DO $$DECLARE r record;

									BEGIN

									FOR r IN SELECT sequence_name FROM information_schema."sequences"

									LOOP

									 EXECUTE 'ALTER SEQUENCE '|| r.sequence_name ||' restart WITH 10000';

									END LOOP;

									END$$;

根据表的id修改

									DO $$

									DECLARE

									 r record;

									 start_value integer := 0;

									BEGIN

									FOR r IN SELECT tablename||'_id_seq' AS sequence_name, tablename FROM pg_tables WHERE schemaname = 'public'

									LOOP

									 EXECUTE 'SELECT max(id)+1 AS max_value FROM ' || r.tablename INTO start_value;

									 IF start_value IS NULL THEN start_value:= 1;

									 END IF;

									 RAISE NOTICE 'start_value % %', r.tablename,start_value;

									 EXECUTE 'ALTER SEQUENCE '|| r.sequence_name ||' restart WITH ' || start_value;

									END LOOP;

									END$$;

补充：postgresql 13 数据库 sequence 的 maxvalue 最大值是多少?

os: centos 7.8.2003

db: postgresql 13.0

版本

									# cat /etc/centos-release

									CentOS Linux release 7.8.2003 (Core)

									# su - postgres

									Last login: Thu Oct 15 09:59:33 CST 2020 on pts/1

									ppostgres@nodepg13-> psql -c "select version();"

									             version             

									---------------------------------------------------------------------------------------------------------

									 PostgreSQL 13.0 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-39), 64-bit

									(1 row)

create sequence

									$ psql

									postgres=# create sequence seq_1;

									CREATE SEQUENCE

									postgres=# select c.relname,c.relkind,s.* from pg_class c,pg_sequence s where c.oid=s.seqrelid;

									 relname | relkind | seqrelid | seqtypid | seqstart | seqincrement |  seqmax  | seqmin | seqcache | seqcycle 

									---------+---------+----------+----------+----------+--------------+---------------------+--------+----------+----------

									 seq_1 | S  | 40968 |  20 |  1 |   1 | 9223372036854775807 |  1 |  1 | f

									(1 row)

									seqmax = 9223372036854775807

									maxvalue

									NO MAXVALUE

									The optional clause MAXVALUE maxvalue determines the maximum value for the sequence. If this clause is not supplied or NO MAXVALUE is specified, then default values will be used. The default for an ascending sequence is the maximum value of the data type. The default for a descending sequence is -1.