Competitive Analysis of Spatial and Multimedia Features in Oracle Database 11g and IBM DB2 9.5 for LUW Spatial Extender (included with all DB2 Editions) Supports “flat earth” coordinates, not accurate for calculations on geometries spanning the earth or poles Indexing (grid) is older, maintenance intensive & less performant Geocoder converts only US addresses to Lat./Long. . . . → Read More: Oracle Database 11g Unstructured Data
|
|||||
|
11g引入了大量compress相关的特性，其中之一便是dbms_compression包；GET_COMPRESSION_RATIO函数可以帮助我们了解压缩某个表后各种可能的影响。换而言之，这个函数可以让我们在具体实施表压缩技术或者测试前，对于压缩后的效果能有一个基本的印象。该包在11gr2中被首次引入，故而使用之前版本的包括11gr1都无缘得用。其次除OLTP压缩模式之外的柱形混合压缩只能在基于Exdata存储的表空间上实现。使用DBMS_COMPRESSION包获取的相关压缩信息是十分准确的，因为在评估过程中Oracle通过实际采样并建立模型表以尽可能还原逼真的数据。 我们可以通过trace来分析其评估过程中的具体操作，可以分成2步： 1. 建立原表的样本表，其采样值基于原表的大小： SQL> create table samp_dss_nation tablespace SCRATCH as select * from dss_nation sample block (50); Table created. 2. 基于采用表建立对应压缩类型的模型表： SQL> create table model_dss_nation tablespace SCRATCH compress for query high as select * from samp_dss_nation; create table model_dss_nation tablespace SCRATCH compress for query high as select * from samp_dss_nation * ERROR at line . . . → Read More: 11g compression 新特性(1) Checked for relevance on 28-May-2009 PURPOSE ——- This article describes the usage of UTL_COMPRESS package. SCOPE & APPLICATION ——————- This article is intended for PL/SQL developers, engineers, or DBAs. 10G: Using the new UTL_COMPRESS Oracle Supplied Package ——————————————————- The purpose of this package is to compress/uncompress RAW, BLOB, or BFILE data. This package is . . . → Read More: 10G: Using the new UTL_COMPRESS Oracle Supplied Package PURPOSE Prior to Oracle9i, any table re-organizations and redefinitions forced the table to be offlined for the duration of the operation. From Oracle9i forward, table re-organizations and redefinitions can be performed online. This note explains how to reorganize a table online. NOTE: This note does not cover the use of row ids. As of 9.2.0.5, . . . → Read More: How to Re-Organize a Table Online 1: CREATING THE LOGMINER DICTIONARY FILE This practice uses the Oracle8i LogMiner utility to create the LogMiner Dictionary file. You will: Set the UTL_FILE_DIR initialization parameter. Create the LogMiner Dictionary File. ASSUMPTIONS: The directory and filenames referenced in the commands in this practice reference the NT operating system. However, simply changing the directory and filename . . . → Read More: Learn How to Use LogMiner there’s no HWM for datafiles, it’s just a virtual term to describe the last block containing data in the data file, which is the minimum size allowed for sizing down the data file. This article intends to provide an SQL script to find tables which are fragmented (i.e Data is much lower then High Water . . . → Read More: Know about Oracle High Water Mark 有一定年头的文档了，记以录之! Oracle expert Dan Hotka explores some internals of the Oracle RDBMS, primarily physical storage of data. This article concentrates on data blocks: how they’re created, how space is really managed inside a tablespace, and some other geeky internal things of interest in the physical storage of data. Reproduced with permission from Pinnacle Publishing. This . . . → Read More: A Close Look at Oracle8i Data Block Internals 有一定年头的文档了，就怕哪天失传了，记以录之。 Subject: SUPTOOL: BBED – 7.3.2+ Database Block Editor Creation Date: 02-JUL-1998 BBED (Block Browser/Editor) —————————- 1. Getting access to BBED: BBED is shipped with Oracle8 releases, and with some Oracle7.3 releases. On UNIX the tool needs to be built using a command of the form: cd $ORACLE_HOME/rdbms/lib make -f ins_rdbms.mk $ORACLE_HOME/rdbms/lib/bbed OR to build . . . → Read More: SUPTOOL:BBED – 7.3.2+ Database Block Editor |
|
||||
|
Copyright © 2012 Oracle Clinic – Maclean Liu的个人技术博客 - All Rights Reserved |
|||||
最新评论