2.有ordered,按照t3驱动t2的顺序join;但是USE_NL(t3)却表示t3作为inner table,也就是被驱动表; 有矛盾,所以oracle 忽视这个hint,执行hash join 代码: --- SQL> select /*+ ordered USE_NL(t3) */ count(*) 2 from t3,t2 3 where t2.object_id=t3.object_id; COUNT(*) --- 7325 Execution Plan...
三、USE_HASH(哈希连接) 当内存能够提供足够的空间时,哈希(HASH)连接是Oracle优化器通常的选择。在哈希连接中,Oracle访问一张表(通常是较大的表),并在内存中建立一张基于连接键的哈希表。然后它扫描连接中其他的表(通常是较大的表),并根据哈希表检测是否有匹配的记录。 只有在数据库初始化参数HASH_JOIN_ENABLED...
Oracle Hint(提示)之USE_CONCAT USE_CONCAT提示的作用和使用方法 USE_CONCAT提示是指导优化器,在处理where子句中的OR条件时,将每一个OR条件都拆成只包含OR条件中的其中一个的子句,然后将这些子句用UNION ALL联接起来,并去除那些在其它子句中已经出现的记录。 USE_CONCAT提示的使用语法如下图所示: 其中: tablespec...
After Oracle Identity Cloud Service logs the user off, it redirects the user browser to the sample application index page. This behavior happens because the sample application adds two parameters post_logout_redirect_uri and id_token_hint to the Oracle Identity Cloud Service logout URL, as p...
In the event handler you can prevent the default reaction of the tab key by using event.preventDefault() whenever event.keyCode is 9. Then put a tab sign in the right position: function allowTab(input) { input.addEventListener("keydown", function(event) { if(event.keyCode == 9) { ...
Return to yourTerminalapplication.Hint:Click theActivitiesmenu to see all open applications. In the terminal, install the VirtualBox package using thednf installcommand. Install using link copied in the previous step. Copy sudodnfinstall-yhttps://download.virtualbox.org/virtualbox/7.0.4/VirtualBox...
Oracle may find a path that allows it to ignore your hint. In a recent example I found that in: select /*+ use_nl(t2) *./ . . . from t1, t2 etc... the hint was ignored, and a hash join was used, but if I used the hints: ...
Oracle Data Guard ensures high availability, data protection, and disaster recovery for enterprise data. The Data Guard implementation requires two databases, one in a primary role and one in a standby role. The two databases compose a Data Guard association. Most of your applications access the ...
The first thing that comes to mind when you starting thinking about forcing how the Oracle Database will execute a query is Optimizer hints. There is anINMEMORYhint available, but that hint justenablesthe use of the In-Memory column store (IM column store) if theINMEMORY_QUERYparamet...
Collapsing/expanding the focused category or complex property with "Left" and "Right" keyboard keys will refocus the property grid to allow continuous keyboard navigation of properties. The hint of the first selected node in the hierarchy is displayed as a hint in the information pane attached to...