1、我做过的项目里有个与人民银行的数据交换,他们用的是分批次的纯文本(直接用c从数据库里导出来)。
譬如201003-1.txt,201003-2.txt...
每个文本控制在10M左右,ftp传输。
简单可靠。
2、(1)
优化前的语句:
Java代码
# Query_time: 5.967435 Lock_time: 0.000129 Rows_sent: 1 Rows_examined: 803401
SET timestamp=1286843575;
select livemessag0_.id as id38_, livemessag0_.isactive as isactive38_, livemessag0_.content as content38_, livemessag0_.createtime as createtime38_, livemessag0_.userid as userid38_, livemessag0_.objectid as objectid38_, livemessag0_.recordid as recordid38_, livemessag0_.type as type38_ from live_message livemessag0_ where (livemessag0_.objectid in (select livescrip1_.id from live_scrip livescrip1_ where livescrip1_.senderid='ff8080812aebac2d012aef6491b3666d')) and livemessag0_.type=2 limit 6;
优化后的语句:
Java代码
select livemessag0_.id as id38_,
livemessag0_.isactive as isactive38_,
livemessag0_.content as content38_,
livemessag0_.createtime as createtime38_,
livemessag0_.userid as userid38_,
livemessag0_.objectid as objectid38_,
livemessag0_.recordid as recordid38_,
livemessag0_.type as type38_
from live_scrip livescrip1_ left join
live_message livemessag0_
on livescrip1_.id=livemessag0_.objectid
where livescrip1_.senderid = 'ff8080812aebac2d012aef6491b3666d' and
livemessag0_.type = 2
limit 6;
总结:尽量少用子查询用表连接的方式代替(如果表连接不是太复杂的话),这样优化后大概能减少1/3的时间,后来发现livemessag0_.objectid竟然没有建立索引。
3、大数据量修改批量提交
博客分类: oracle
SQLBlog
引自:http://sunxboy.iteye.com/blog/153886
大数据量修改批量提交
例如: 原来的语句为
____DELETE FROM HUGETABLE WHERE condition;
可用如下语句代替:
____BEGIN
________LOOP
____________DELETE FROM HUGETABLE
____________WHERE condition
____________AND ROWNUM<10000;
____________EXIT WHEN SQL%NOTFOUND;
____________COMMIT;
________END LOOP;
____END;
百万千万级数据量 数据库优化(二)
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转载自lixg425.iteye.com/blog/1874940
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