PermaLink DB2 Transactioning Harder Because It's Missing MVCC?02/02/2006 02:08 PM
Saw this interesting comment on the JBoss blog.  It's part of a "Hibernate/EJB3 tuning" blog entry, but I found it interesting that just about all the other popular RDBMS's support MVCC (it basically allows you to work on a copy of data as part of your transaction before writing it to disk rather than locking data and working on the data directly).  Wonder if that's why DB2 is so resource hungry?
Comments :v

1. Andy02/18/2006 16:11:10
Homepage: http://jboss.org/jbossBlog/blog/acoliver/


actually in theory DB2 style (I call "old style") locking is less expensive than MVCC. Making a copy is more expensive. However in concurrency sometimes doing the more expensive thing increased perceieved perforamance. Think of a car wash. If I only staff one car line then my costs are lower and I theoretically will make more profit right? However, if the line is 2x longer and everyone sees this and leaves (timeout) while waiting then it won't be. Same general concept. Using more resources for the more expensive concurrent lock gives you better performance. However many developers don't know how to use MVCC anyhow and end up doing select for update everywhere and getting DB2 style locking anyhow....




Start Pages
RSS News Feed RSS Comments Feed CoComment Integrated
The BlogRoll
Calendar
June 2024
Su
Mo
Tu
We
Th
Fr
Sa
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
Search
Contact Me
About Ken
Full-stack developer (consultant) working with .Net, Java, Android, Javascript (jQuery, Meteor.js, AngularJS), Lotus Domino