Hibernate Oracle sessions not be closed correctly
We got escalation today, a lot of services are very slow or stop working. Our Oracle database(10g) admin has found that there are a huge number of unclosed sessions in the Oracle database. In...
Just One Pure ITer
We got escalation today, a lot of services are very slow or stop working. Our Oracle database(10g) admin has found that there are a huge number of unclosed sessions in the Oracle database. In...
现在大数据已经成为企业信息化热点方向之一,很多企业都已经开始或者准备利用大数据大干一场,降低成本、提升数据价值,从而实现智能决策,但是从以 Hadoop 为代表的大数据技术面世以来,将近 10 年的时间,除了几家大型互联网公司以外,企业能够用好大数据的案例远远没有期望的那么多。据国外一家咨询公司 2015 年统计,只有 27% 的公司认为他们的大数据计划是成功的,而只有 8% 的认为是非常成功的。即便是在 POC 阶段,很多企业的平均成功率才只有 38%。
工作中,曾有同事问我以下sql的效率如何,这里扩展一下这个问题并进行分析,主要说明where子句中的子查询和函数执行次数及索引使用情况。
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select * from trd_fundjour a where oc_date = (select collect_date from hscon.sys_arg); |
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