随笔分类 -  PostgreSQL Deep

pg中删除的页是否仍被访问
摘要:昨天看到微信群中,有人提问:pg对于标记为删除的页,是否会扫描到? 今天做了一下测试,发现如果删除的是表的最后连续的几个页(根据ctid来确定数据插入先后,只讨论有insert的情况)中的数据,最后几个页经过vacuum后,会被释放回操作系统,自然不会被扫描到,但如果不是最后的页会不会扫描到,下面测 阅读全文

posted @ 2019-03-13 20:21 Still water run deep 阅读(244) 评论(0) 推荐(1)

How do you build a database?
摘要:在reddit上看到的一篇讲解数据库实现的文章,非常有意思,在这里记录一下。 回答者technical_guy: Its a great question, and deserves a long answer. Most database servers are built in C, and s 阅读全文

posted @ 2016-04-05 21:56 Still water run deep 阅读(275) 评论(0) 推荐(0)

Following a Select Statement Through Postgres Internals
摘要:This is the third of a series of posts based on a presentation I did at the Barcelona Ruby Conference called “20,000 Leagues Under ActiveRecord.” (pos 阅读全文

posted @ 2016-03-13 23:41 Still water run deep 阅读(425) 评论(0) 推荐(0)

Discovering the Computer Science Behind Postgres Indexes
摘要:This is the last in a series of Postgres posts that Pat Shaughnessy wrote based on his presentation at the Barcelona Ruby Conference. You can also wat 阅读全文

posted @ 2016-03-13 00:28 Still water run deep 阅读(248) 评论(0) 推荐(0)

Heap Only Tuples (HOT)
摘要:Introduction------------The Heap Only Tuple (HOT) feature eliminates redundant index entries andallows the re-use of space taken by DELETEd or obsolet... 阅读全文

posted @ 2015-12-15 00:20 Still water run deep 阅读(1089) 评论(0) 推荐(0)

PgSQL · 特性分析 · 谈谈checkpoint的调度
摘要:在PG的众多参数中,参数checkpoint相关的几个参数颇为神秘。这些参数与checkpoint的调度有关,对系统的稳定性还是比较重要的,下面我们为大家解析一下,这要先从PG的数据同步机制谈起。PG的数据同步机制众所周知,数据库的后台进程在执行用户事务时,发生的数据更改是先写入缓冲池中,对应PG就... 阅读全文

posted @ 2015-12-06 18:19 Still water run deep 阅读(712) 评论(0) 推荐(0)

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