Slash Boxes
NOTE: use Perl; is on undef hiatus. You can read content, but you can't post it. More info will be forthcoming forthcomingly.

All the Perl that's Practical to Extract and Report

The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
More | Login | Reply
Loading... please wait.
  • Fred and Mary start with:

    1 A
    2 B
    3 C

    Fred starts a transaction and updates the first two rows so the table that looks like:

    1 X
    2 Y
    3 C

    In the mean time Mary has started and finished a transaction that updates the third row:

    1 A
    2 B
    3 Z

    which means that Fred is seeing the "old" version of row three, and the table as a whole reflects something that will never have existed in the database.

    Make sense?

    • Oh! I replied to Aristotle without thinking too carefully about your reply. I can see how this could occur, but it's problematic because then things aren't atomic. If you take actions based upon this, you can still corrupt your data. You update row 3 because 'C' is there, but it's really not. Now you have a race condition because consistent reads aren't. Or did I misunderstand something?