RE: Does NT write to random locations on disk?

At 01:55 PM 3/9/01 -0800, you wrote:
>Oracle datafiles are formatted into blocks. Data is read either physically
>by block or an indexed block number. If you compress using zip and then
>uncompress, the blocks have not changed. If you reorg the file the blocks
>will probably change and the data wont be where Oracle thinks it is.
>

I'm working from logic rather than specific knowledge of Oracle here, so I could be way off base. But if you are set up to use a cooked rather than raw file system, then the block number that Oracle uses should be file-relative rather than disk-relative, i.e. the block labelled '34' would be the 34th or 35th block *in the file* rather than *on the disk*. No matter how much you defrag, zip, unzip, copy, mash, spit on, or otherwise vilify the file, it still ends up with the same data in that block. Theoretically.

Dennis Taylor

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Author: Dennis Taylor
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