必应词典为您提供dynamic-sampling的释义,网络释义: 动态采样;动态累积法;动态取样;
47SQL>altersessionsetoptimizer_dynamic_sampling=8;4849Session altered.5051SQL>selectcount(*)fromjack;5253ExecutionPlan54---55Planhash value:12050235015657---58|Id|Operation|Name|Rows|Cost (%CPU)|Time|59---60|
对于没有收集统计信息的表,Oracle为了能够得到相对准确的执行计划,会在执行SQL之前对SQL语句涉及到的表做动态采样(Dynamic Sampling,从Oracle 11.2.0.4开始称之为Dynamic Statistic)。 有两种方法可以开启动态采样: (1)将参数OPTIMIZER_DYNAMIC_SAMPLING的值设为大于或等于1。从Oracle 10g开始,该值默认为2,若设置为0,...
the optimizer will tend to use dynamic sampling only in some cases when a table is unanalyzed. This includes the case of global temporary tables without statistics but doesn’t ensure that dynamic sampling will be used against all unanalyzed tables. In Oracle Database...
在Oracle中,什么是动态采样(Dynamic Sampling)? ♣ 答案部分 对于没有收集统计信息的表,Oracle为了能够得到相对准确的执行计划,会在执行SQL之前对SQL语句涉及到的表做动态采样(Dynamic Sampling,从Oracle 11.2.0.4开始称之为Dynamic Statistic)。 有两种方法可以开启动态采样: ...
-- optimizer_dynamic_sampling默认值为2,我先改为5,然后查看效果 ning@MAA> alter session set optimizer_dynamic_sampling=5; Session altered. ning@MAA> select OBJECT_ID, OBJECT_NAME, OWNER FROM t3 where object_id < 4000; 3833 rows selected. ...
这个参数共分为10个等级: 从10g开始,oracle默认把optimizer_dynamic_sampling的等级设为2,那就会出现如果对象没有统计信息,oracle就会在每次查询的时候进行采样,所以oracle看起来会相当的智能。
论文题目:Key-Value Memory Networks for Directly Reading Documents 原文链接: link 文章来源:ACL2016 学术机构:Facebook AI Research / Carnegie Mellon University 转载请注明出处… Dylan发表于学习NLP... Contrastive Learning with Adversarial Examples阅读笔记 TLDR这篇文章发表于NeurIPS 2020,属于对抗样本在其它领域...
optimizer_dynamic_sampling 用于控制动态采样的等级。 说明 该变量从 V4.2.0 版本开始引入。 属性描述 参数类型 int 默认值 1 取值范围 [0,1] 生效范围 Global Session 是否只读 否 是否参与序列化 是 是否重启生效 否 示例 set optimizer_dynamic_sampling = 0; set global optimizer_dynamic_sampling = 1...
Dynamic sampling (DS) was introduced to improve the optimizer's ability to generate good execution plans. This feature was enhanced and renamed Dynamic Statistics in Oracle Database 12c. The most common misconception is that DS can be used as a substitut