Query to find the eligible indexes for rebuilding
QuerytofindtheeligibleindexesforrebuildingThefollowingscriptcanbeusedtodeterminewhichindexeswouldbenefitfromarebuild,howmuchtheywillshrinkby(assuming8...
mysql创建Bitmap_Join_Indexes中的约束与索引
现象:创建Bitmap Join Indexes时出现ORA-25954报错: 维的主键或唯一约束条件缺失。 53vi.Com 原因:受到约束与索引的影响。
Reverse Key Indexes反向索引
ReverseKeyIndexes反向索引AreversekeyindexisatypeofB-treeindexthatphysicallyreversesthebytesofeachindexkeywhilekeepingthecolumnorder.反向索引就是将正常的键值头尾调换后再进行存储...
《Microsoft Sql server 2008 Internals》读书笔记--第六章Indexes:Internals and Management(1)
《MicrosoftSqlserver2008Internals》索引文件夹:《MicrosoftSqlserver2008Internals》读书笔记--文件夹索引在第五章主要学习了table的内部存储结构,第七章《Specialstorage》中将继续深入学习存储机制,那将是本书最难理解的一章。...
14.8.9 Clustered and Secondary Indexes
14.8.9ClusteredandSecondaryIndexes每个InnoDB表有一个特殊的索引称为clusteredindex用于存储数据。通常,clusteredindex是主键的同义词。为了使查询得到最好的性能,插入,和其他数据库操作,你必须了解InnoDB如何使用clusteredin...
Creating Spatial Indexes(mysql 创建空间索引 The used table type doesn't support SPATIAL indexes)
For MyISAM tables,MySQLcancreatespatialindexesusingsyntaxsimilartothatforcreatingregularindexes,butextendedwiththe SPATIAL keyword.Currently,columnsin...
dba_indexes视图的性能分析
前端时间,在监控系统中加入了index的状态是否为unusable,以及其并行度是否有设置的监控:
How Indexes Are Stored
reference: http://docs.oracle.com/cd/B28359_01/server.111/b28318/schema.htm#CHDJGADJ当创建索引的时候,Oracle会自动在表空间中分配一个索引段来存储索引数据。你可以控制索引段的空间分配并且通过以下两种方式对这部分保...
14.3 Using Partitioned Indexes for Performance 使用分区索引
原文:Similartopartitionedtables,partitionedindexesimprovemanageability,availability,performance,andscalability.Theycaneitherbepartitionedindependently(g...
python pandas中嵌套的DataFrames / Indexes
AimIamtryingtomanipulatedatafromsomevideotrackingexperimentsusingpythonpandas.Iplacedanumberofpointmarkersonastructure,andtrackedthepoints'XYcoordinat...