LightDB23.4 支持alter session enable/disbale parallel dml/ddl/query

功能介绍

为了兼容Oracle数据库的语法，在LightDB23.4版本新增支持alter session enable/disbale parallel dml/ddl/query语句。这个语句只在Oracle兼容模式下生效，并且只是一个语法糖。

使用示例

1. Oracle模式下使用，可以正确输入

lightdb@oracle_test=# show lightdb_dblevel_syntax_compatible_type ;
 lightdb_dblevel_syntax_compatible_type 
----------------------------------------
 Oracle
(1 row)

lightdb@oracle_test=# 
lightdb@oracle_test=# 
lightdb@oracle_test=# alter session enable parallel dml;
lightdb@oracle_test=# alter session enable parallel ddl;
lightdb@oracle_test=# alter session enable parallel query;
lightdb@oracle_test=# 
lightdb@oracle_test=# alter session disable parallel dml;
lightdb@oracle_test=# 
lightdb@oracle_test=# alter session disable parallel ddl;
lightdb@oracle_test=# 
lightdb@oracle_test=# alter session disable parallel query;
lightdb@oracle_test=# 

2. 非Oracle模式下使用，会报错

lightdb@postgres=# show lightdb_dblevel_syntax_compatible_type ;
 lightdb_dblevel_syntax_compatible_type 
----------------------------------------
 off
(1 row)

lightdb@postgres=# 
lightdb@postgres=# 
lightdb@postgres=# alter session enable parallel dml;
ERROR:  "ALTER SESSION" is only support in Oracle compatible mode
LINE 1: alter session enable parallel dml;
              ^
lightdb@postgres=# 
lightdb@postgres=# alter session enable parallel ddl;
ERROR:  "ALTER SESSION" is only support in Oracle compatible mode
LINE 1: alter session enable parallel ddl;
              ^
lightdb@postgres=# 
lightdb@postgres=# alter session enable parallel query;
ERROR:  "ALTER SESSION" is only support in Oracle compatible mode
LINE 1: alter session enable parallel query;
              ^
lightdb@postgres=# 
lightdb@postgres=# 
lightdb@postgres=# alter session disable parallel dml;
ERROR:  "ALTER SESSION" is only support in Oracle compatible mode
LINE 1: alter session disable parallel dml;
              ^
lightdb@postgres=# 
lightdb@postgres=# alter session disable parallel ddl;
ERROR:  "ALTER SESSION" is only support in Oracle compatible mode
LINE 1: alter session disable parallel ddl;
              ^
lightdb@postgres=# 
lightdb@postgres=# alter session disable parallel query;
ERROR:  "ALTER SESSION" is only support in Oracle compatible mode
LINE 1: alter session disable parallel query;
              ^
lightdb@postgres=#