背景介绍

Oracle数据库支持设置sequence的minvalue为-1000000000000000000000000000，在用户迁移到LightDB时，sequence设置minvalue为-1000000000000000000000000000会报错。为了兼容Oracle数据库的使用习惯，在LightDB24.1版本中，对于minvalue小于INT64_MIN（-9223372036854775808）做了处理，使得minvalue值被设置为INT64_MIN。

使用约束：

• oracle兼容模式下生效

使用示例

1. 在oracle兼容模式下

lightdb@oracle_test=# show lightdb_dblevel_syntax_compatible_type ;lightdb_dblevel_syntax_compatible_type 
----------------------------------------Oracle
(1 row)lightdb@oracle_test=# create sequence s1 minvalue -1000000000000000000000000000;
NOTICE:  minvalue out of range, set sequence min value to -9223372036854775808
CREATE SEQUENCE
lightdb@oracle_test=# \d+ s1Sequence "public.s1"Type  |        Start         |       Minimum        |       Maximum       | Increment | Cycles? | Cache 
--------+----------------------+----------------------+---------------------+-----------+---------+-------bigint | -9223372036854775808 | -9223372036854775808 | 9223372036854775807 |         1 | no      |     1lightdb@oracle_test=# 

2. 非oracle兼容模式

lightdb@postgres=# show lightdb_dblevel_syntax_compatible_type ;lightdb_dblevel_syntax_compatible_type 
----------------------------------------off
(1 row)lightdb@postgres=# 
lightdb@postgres=# create sequence s1 minvalue -1000000000000000000000000000;
ERROR:  value "-1000000000000000000000000000" is out of range for type bigint
lightdb@postgres=# \d+ s1
Did not find any relation named "s1".
lightdb@postgres=#