oracle cursor_sharing similar 关于设值的一些问题
关于oracle cursor_sharing= similar参数的一些测试
当你通过alter system set cursor_sharing="SIMILAR" 时
buyer_id为字符串类型，如果显示的给标明， 如下时，测试结果只会编译一次
测试数据
select address,hash_value, executions, sql_text from v$sql v$sql where upper(sql_text) like 'SELECT * FROM APPLY_BUYER%'; SELECT * FROM APPLY_BUYER where buyer_id='13111'and buyer_name='a'; SELECT * FROM APPLY_BUYER where buyer_id='13112'and buyer_name='b'; SELECT * FROM APPLY_BUYER where buyer_id='13113'and buyer_name='c'; SELECT * FROM APPLY_BUYER where buyer_id='13114'and buyer_name='d'; SELECT * FROM APPLY_BUYER where buyer_id='13115'and buyer_name='e'; SELECT * FROM APPLY_BUYER where buyer_id='13116'and buyer_name='f'; SELECT * FROM APPLY_BUYER where buyer_id='13117'and buyer_name='g'; select address,hash_value, executions, sql_text from v$sql v$sql where upper(sql_text) like 'SELECT * FROM APPLY_BUYER%';
测试结果
2 2FC3F204 1136223711 7 SELECT * FROM APPLY_BUYER where buyer_id=:"SYS_B_0"and buyer_name=:"SYS_B_1"
如果我们传的数字时，让系统转化时，编译每次都不会一样，但是他的地址和编码都是一样？不太明白
测试数据
select address,hash_value, executions, sql_text from v$sql v$sql where upper(sql_text) like 'SELECT * FROM APPLY_BUYER%'; SELECT * FROM APPLY_BUYER where buyer_id=13101 and buyer_name='aa'; SELECT * FROM APPLY_BUYER where buyer_id=13102 and buyer_name='bb'; SELECT * FROM APPLY_BUYER where buyer_id=13103 and buyer_name='cc'; SELECT * FROM APPLY_BUYER where buyer_id=13104 and buyer_name='dd'; SELECT * FROM APPLY_BUYER where buyer_id=13105 and buyer_name='ee'; SELECT * FROM APPLY_BUYER where buyer_id=13106 and buyer_name='ff'; SELECT * FROM APPLY_BUYER where buyer_id=13107 and buyer_name='gg'; select address,hash_value, executions, sql_text from v$sql v$sql where upper(sql_text) like 'SELECT * FROM APPLY_BUYER%';
测试结果
9 2FE57024 1923906214 1 SELECT * FROM APPLY_BUYER where buyer_id=:"SYS_B_0" and buyer_name=:"SYS_B_1" 10 2FE57024 1923906214 1 SELECT * FROM APPLY_BUYER where buyer_id=:"SYS_B_0" and buyer_name=:"SYS_B_1" 11 2FE57024 1923906214 1 SELECT * FROM APPLY_BUYER where buyer_id=:"SYS_B_0" and buyer_name=:"SYS_B_1" 12 2FE57024 1923906214 1 SELECT * FROM APPLY_BUYER where buyer_id=:"SYS_B_0" and buyer_name=:"SYS_B_1" 13 2FE57024 1923906214 1 SELECT * FROM APPLY_BUYER where buyer_id=:"SYS_B_0" and buyer_name=:"SYS_B_1" 14 2FE57024 1923906214 1 SELECT * FROM APPLY_BUYER where buyer_id=:"SYS_B_0" and buyer_name=:"SYS_B_1" 15 2FE57024 1923906214 1 SELECT * FROM APPLY_BUYER where buyer_id=:"SYS_B_0" and buyer_name=:"SYS_B_1"
结果：
设值时，类型是由开发人员去设，不要由系统去转！很浪费性能的