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And so my end conclusion in all of this is: if you want autonomy, and the ability to own and control your own domain and projects – it is your job to push information and build trust with your team members. In other words, you need to learn and do the following: Follow [...] 在production环境上，使用也要小心，因为该pending timeout的DDL enqueue会阻塞后来的DML操作。 http://t.cn/zTTrvPb DDL_LOCK_TIMEOUT in 11g. 原理是, Oracle的锁处理是一种排队机制, 排队是分先后的, 排在队列前面的操作会阻塞排在后面的操作, 也即当DDL被阻塞时, DDL操作本身会阻塞一批后续的DML操作, 这可能会给系统带来很大的负面风险. http://t.cn/zlZDD0w 也谈大公司病1——正确是最大的错误,1. 做正确的事比正确的做事更重要, 但是, 大公司中存在太多的正确, 当公司倡导的n种正确出现冲突，哪一种更正确? 2. 流程与效率的冲突问题, 3. 正确延误了学习，长期看带来能力降低; 正确延误了创新，阻碍了变革。 Being able to recover quickly from failure is more important than having failures less often. 也即MTTR is more important than MTBF ( 相对于更少的出现故障来讲, 可以快速的从故障中恢复过来, 要更加重要). 在此文中, Eric Brewer有个补充, “由于故障的复杂度在不断提高,MTTR显得更加重要了”. 链接: mttr-mtbf-for-most-types-of-f/ http://t.cn/zjQFy7M Dare [...] Oracle 性能优化 from james tong Cap 理论与实践 from james tong To date, nobody has ever discovered a data layout that is efficient for all usage patterns. As a general rule, simpler data layouts are often faster to write, while fancier ones can boost query performance. Specific tradeoffs include, but hardly are limited to: Big blocks of data compress better, and can be also be faster [...] |
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