表压缩的用法（技术交流）
我现在有个表，已经500G了，现在想要启用压缩，让这个表缩小下空间？alter table 。。 compress这个操作可行吗？以下几个问题1：对于新插入的数据，是压缩的吗？insert方式增加、load方式增加都会压缩吗？2：对于历史数据能压缩吗？难道做下reorg就可以吗？3：能在线做吗？需要表空间有剩余500g吗？...显示全部
查看其它 9 个回答drdb2的回答
回复 7# wangzk0206
http://www-01.ibm.com/support/kn ... c/doc/c0052331.html
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Table-level compression dictionary creation
Table-level compression dictionaries for tables that you enable for adaptive or classic row compression can be built automatically or manually. Tables that you enable for adaptive compression include page-level data dictionaries, which are always automatically created.
Automatic dictionary creation
Starting with DB2® Version 9.5, a table-level compression dictionary is created automatically if each of the following conditions is met:
You set the COMPRESS attribute for the table by using the CREATE TABLE or ALTER TABLE statement with the COMPRESS YES ADAPTIVE or COMPRESS YES STATIC clause.
A table-level compression dictionary does not already exist for the table.
The table contains sufficient data for constructing a dictionary of repeated data.
http://www-01.ibm.com/support/kn ... c/doc/c0052331.html
"
Table-level compression dictionary creation
Table-level compression dictionaries for tables that you enable for adaptive or classic row compression can be built automatically or manually. Tables that you enable for adaptive compression include page-level data dictionaries, which are always automatically created.
Automatic dictionary creation
Starting with DB2® Version 9.5, a table-level compression dictionary is created automatically if each of the following conditions is met:
You set the COMPRESS attribute for the table by using the CREATE TABLE or ALTER TABLE statement with the COMPRESS YES ADAPTIVE or COMPRESS YES STATIC clause.
A table-level compression dictionary does not already exist for the table.
The table contains sufficient data for constructing a dictionary of repeated data.
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