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PostgreSQL提供了好几种索引类型：B-tree, Hash, GiST, SP-GiST和GIN 。B-tree索引也可以用来按照排序顺序检索数据。这并不总是比一个简单的扫描和排序快， 但通常是有帮助的。Hash 索引只能处理简单的等于比较。当一个索引了的列涉及到使用= 操作符进行比较的时候，查询规划器会考虑使用 Hash 索引。GiST 索引不是...

在线备份以及即时恢复(PITR)组合文件系统备份与WAL文件的备份。如果需要恢复，我们就恢复备份， 然后重放备份了的WAL文件，把备份恢复到当前的时间。注意: pg_dump和 pg_dumpall没有产生文件系统级别备份，并且不能作为 连续归档解决方案的一部分。比如备份是符合逻辑的并且不包含 WAL重放使用的足够信息。...

postgres 20079     1  0 Jul07 ?        00:00:41 /usr/pgsql-9.2/bin/postmaster -p 60904 -D /u01/app/postgres/data/monicrmpostgres 20081 20079  0 Jul07 ?        00:00:00 postgres: logger process             &nb...

-----check INDEX SIZE more than 1 gega bytesSELECT OWNER AS OWNER,       SEGMENT_NAME AS SEGMENT_NAME,       SEGMENT_TYPE,       SUM(BYTES) / 1024 / 1024 AS "SEGMENT_SIZE(M)"  FROM DBA_SEGMENTS...

tetrix03_cafia2odb02alert_tetrix03.logUse ADRCI or Support Workbench to package the incident.See Note 411.1 at My Oracle Support for error and packagingdetails.Errors in file/u01/app/oracle/diag/rdbms/tetrix03_cafia2odb02/tetrix03/trace/tetrix03_smon_14876870.trc:ORA-00604: e...

Case study: http://www.ubtools.com/jira/browse/QA-20https://support.oracle.com/epmos/faces/DocumentDisplay?_afrLoop=122257289878491&parent=DOCUMENT&sourceId=39308.1&id=9316980.8&_afrWindowMode=0&_adf.ctrl-state=sjvx2jrlp_49Investigation: https://dioncho.wordpress.com/2009/06/09/707/...

Forcing Log SwitchesA log switch occurs when LGWR stops writing to one redo log group and starts writing to another. By default, a log switch occurs automatically when the current redo log file group fills.You can force a log switch to make the currently active group inactive and available for r...

FRA空间满:1、备份Archivelog，释放空间。2、手工清除Flashback log： alter database flashback off。在数据库open阶段，rvwr进程需要加载闪回日志文件，由于找不到所以无法正常启动，而在关闭flashback后,rvwr进程被关闭，相应的闪回文件也被删除。原因: 刚刚看到闪回日志占用空间太多，直接统计OS命令rm删除，导致...

there some ways, one of it flashback table to 5minutes beforeflashback table MyTable to timestamp to_timestamp(sysdate-5/1440) --five minutes agoor you can just query it (not changing table)(flashback query)SELECT * FROM MyTable AS OF TIMESTAMP (sysdate -5 /1440);but these are not ...

http://dev.mysql.com/downloads/cluster/

https://docs.docker.com/engine/tutorials/dockerizing/

Add disk size / Resize a partition / Create a partition

SELECT DISTINCT TOP 100t.TEXT QueryName,s.execution_count AS ExecutionCount,s.max_elapsed_time AS MaxElapsedTime,ISNULL(s.total_elapsed_time / s.execution_count, 0) AS AvgElapsedTime,s.creation_time AS LogCreatedOn,ISNULL(s.execution_count / DATEDIFF(s, s.creation_time, GET...

根据IP地址和掩码如何快速计算出子网和广播地址？IP地址：201.222.10.60，掩码：255.255.255.248 计算过程： 256 -248=8   60/8    =7    SUBNET= 7*8      BROADCAST =8*8-1result： SUBNET=201.222.10.56  ...

https://www.rackspace.com/cloud/sites

A Web API Design Methodologyhttps://www.infoq.com/articles/web-api-design-methodology/Article Series: Web APIs: From Start to Finishhttps://www.infoq.com/articles/Web-APIs-From-Start-to-Finish RESTful Web APIs  http://restfulwebapis.com

http://dev.mysql.com/doc/refman/5.7/en/storage-engines.html16.1 Setting the Storage Engine16.2 The MyISAM Storage Engine     16.3 The MEMORY Storage Engine16.4 The CSV Storage Engine     16.5 The ARCHIVE Storage Engine16.6 The ...

GET 从指定的url上获取内容POST 提交body中的内容给服务器中指定的url中，属于非幂等的(non-idempotent)请求HEAD 从指定的url上获取header内容(类似Get方式)TRACE Allows a programmer to see how the client's message is modified as it passes through a series of proxy...

ping和host,dig,nslookup是两种不同类型的处理DNS的方式ping,首先会查询本地的/etc/hosts文件，然后才会查询DNS服务器，这样做有啥好处？效率高。host,dig,nslookup三个命令是一样的，不会查询本地的/etc/hosts文件，如果查询DNS服务器没有结果，那么直接返回无结果，此时，即使本地有配置/etc/hosts文件也是没有用...

安装linux系统之RHEL7或CENTOS7系统(完整版)http://jingyan.baidu.com/article/c35dbcb0f3565a8916fcbca4.html