The term “lossless compression” is a phrase critical to any compression discussion. I describe lossless compression as the process that allows you to expand something that has been compressed and end up with the exact same thing you started with. I know, you’re thinking “That’s crazy! How could you end up with something different?” Let me give you a quick example. Most, if not all, of you have probably messed around with some kind of digital imaging on a computer. If you have, then you most likely have played around with something called a JPG? JPG is actually a shortened form of JPEG which stands for Joint Photographic Experts Group. I know, it’s hard to believe that someone would abbreviate an acronym, but that discussion is for a different post. JPEG is a form of compression called “lossy compression” and is used for images (photographs). The term lossy compression (as apposed to lossless compression) does lose information every time you save the JPEG. The more you save a JPEG (therefore re-compressing an already compressed image) the more information about that image you lose until the image is no longer acceptable. This is not a process you’d like to follow with your data.
This “post” has turned into a very long article. Since my intent is to NOT publish articles via a blog, I am going to break this post into sections to make it a bit easier to read and a whole lot easier for me to edit and complete. I will publish all of the “parts” at one time with back and forth links to the different portions. I hope this is OK with you all. Now onto the first part of my zEDC saga.
This is the URL to get to the second part of the post… “Do you like compression? Then you’re going to love zEnterprise Data Compression (zEDC) –- (Part 2)”
A friend recently ask me about DSNDB01.SPT01, compression and DB2 10. It seems like some folk said there would be no need to compress SPT01 once you migrated to DB2 10 because DB2 10 uses LOBs with SPT01. In my opinion, I don’t think that is accurate anymore. I’m not even sure it was ever factual. However, in my opinion (important phrase in this post, remember it) you can still compress SPT01, and in fact, there may still ne a need for you to compress it…… Continue reading »
You keep hearing about this and that trace that you should be running: statistics class 1,3,4,5, and 6, accounting class 1,2,3,7,8, audit, performance, etc… Even in this blog, every few months I discuss some trace that you should consider starting or expanding…… Continue reading »