[ http://issues.apache.org/jira/browse/DERBY-1067?page=all ]
Mike Matrigali updated DERBY-1067:
----------------------------------
Description: (was: I am reviewing this patch. (mike matrigali)
2 major concerns with this patch:
1) The timestamp is implemented in runtime, but not persistent. The container
can be thrown away as soon as someone is not referencing it, which I believe
can happen in the holdable cursor case. If you want to implement the
timestamp then I think you have to add to the container header
(see FileContainer line 278 for container header description), and
follow code that updates estimated row count for how it is updated and
read. Note that doing this is an UPGRADE issue, and you should think
about soft vs. hard upgrade for this feature.
For more comments about upgrade I need to know your plan. On soft upgrade
will timestamp be bumped or not. I would prefer that it not be changed.
The current assumption for "unused" fields in store is that they are
guaranteed with a specific value (usually 0) before an upgrade. So
on hard upgrade we know the starting value. Also if you change it in
soft upgrade then you have to make sure that all previous of 10.1 don't
have a problem with that field not being 0 - sometimes there are assertions
about the field being 0, don't know for sure in this particular case.
2) I would have expected tests specific to this change associated with the
patch.
some testing areas of concern:
o soft upgrade, make sure 10.1 works correctly on a 10.2 soft upgrade run.
o what happens on timestamp overflow?
minor comments:
general comments:
I would have rather seen the timestamp tied to the reusable rowlocation
concept rather than tied to compress. While true the only thing in the
current code that breaks this is compress, so this may just be my itch.
should timestamp be more "time" related. A single db may reuse a containerid,
but only after a shutdown/reboot cycle. A time based timestamp would mean
the new container timestamp would be different from the old one. Probably
does not matter for held cursors, but what makes sense for the generic new
timestamp feature?
questions:
why do you get the timestamp for the open cursor at close rather than open?
style comments:
don't want to start coding style arg here, and admit not all store code is
perfect. Most the access code is consistent though, and uses the brace on
separate line standard.
GenericScanController.java, reOpenAfterEndTransaction() - coding style does
not match surrounding code (ie. brackets on same lines and if condition
on same line).
GenericScanController.java, closeForEndTransaction() - coding style does
not match code in same routine. I think minimum style in same routine
should be consistent.)
I am reviewing this patch. (mike matrigali)
2 major concerns with this patch:
1) The timestamp is implemented in runtime, but not persistent. The container
can be thrown away as soon as someone is not referencing it, which I believe
can happen in the holdable cursor case. If you want to implement the
timestamp then I think you have to add to the container header
(see FileContainer line 278 for container header description), and
follow code that updates estimated row count for how it is updated and
read. Note that doing this is an UPGRADE issue, and you should think
about soft vs. hard upgrade for this feature.
For more comments about upgrade I need to know your plan. On soft upgrade
will timestamp be bumped or not. I would prefer that it not be changed.
The current assumption for "unused" fields in store is that they are
guaranteed with a specific value (usually 0) before an upgrade. So
on hard upgrade we know the starting value. Also if you change it in
soft upgrade then you have to make sure that all previous of 10.1 don't
have a problem with that field not being 0 - sometimes there are assertions
about the field being 0, don't know for sure in this particular case.
2) I would have expected tests specific to this change associated with the
patch.
some testing areas of concern:
o soft upgrade, make sure 10.1 works correctly on a 10.2 soft upgrade run.
o what happens on timestamp overflow?
minor comments:
general comments:
I would have rather seen the timestamp tied to the reusable rowlocation
concept rather than tied to compress. While true the only thing in the
current code that breaks this is compress, so this may just be my itch.
should timestamp be more "time" related. A single db may reuse a containerid,
but only after a shutdown/reboot cycle. A time based timestamp would mean
the new container timestamp would be different from the old one. Probably
does not matter for held cursors, but what makes sense for the generic new
timestamp feature?
questions:
why do you get the timestamp for the open cursor at close rather than open?
style comments:
don't want to start coding style arg here, and admit not all store code is
perfect. Most the access code is consistent though, and uses the brace on
separate line standard.
GenericScanController.java, reOpenAfterEndTransaction() - coding style does
not match surrounding code (ie. brackets on same lines and if condition
on same line).
GenericScanController.java, closeForEndTransaction() - coding style does
not match code in same routine. I think minimum style in same routine
> support holdable Scrollable Updatable Resultsets
> ------------------------------------------------
>
> Key: DERBY-1067
> URL: http://issues.apache.org/jira/browse/DERBY-1067
> Project: Derby
> Type: Sub-task
> Reporter: Andreas Korneliussen
> Assignee: Andreas Korneliussen
> Attachments: DERBY-1067.diff, DERBY-1067.stat
>
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