jscan issues

Michael Neumann mneumann at ntecs.de
Thu Aug 9 14:46:11 PDT 2007


Hi,

I've played a bit with jscan, especially rolling a journal back and forth.

I created a journal:

  mountctl -a -w /tmp/journal /mnt:test

Stopped it:

  mountctl -d /mnt:test

The journal stream ("scan -d /tmp/journal" output) looks like this:

  STREAM c002 11aee6a84680a5a8 {
    DISCONT
  }
  STREAM c100 11aee6a84680a5aa{
    ...
  }
  ...
  STREAM c100 11aee6a84680a5b4
    ...
  }
  STREAM c002 11aee6a84680a5b6
    DISCONT
  }
Now I can play the journal with:

  jscan -m /tmp/id /tmp/journal
  cat /tmp/id # => 11aee6a84680a5b6
So far so good. Everything works as expected. The files appear in
the local directory.
Now I try to roll back one transaction:

  jscan -m /tmp/id -c 1 -u /tmp/journal
  cat /tmp/id # => 11aee6a84680a5b5
Strange, this id (11aee6a84680a5b5) doesn't exist. I assume it describes 
the position (beween "b4" and "b6"). But while /tmp/id gets updated, the 
files do not disappear.

Ahhhh, I learned about the -o reversable option

  mountctl -a -w /tmp/journal -o reversable /mnt:test

will do the magic!!!

Great stuff! Thanks!

BTW, there is a typo in the usage output of jscan.
"[-o/O output_trnasid_file/none]" should be
"[-o/O output_transid_file/none]".
Regards,

  Michael





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