Characterising the issues is the issue.
I'm using JENA-1089 as a chance to do some clearing out. There are some
DSG implementations that are passed their use-by date. A mild attack of
code rot.
Some got written for some specific purposes, then left in case they were
"useful" (I guess). They are "general" style working with collections
of graphs from any storage.
One definitely is only suitable for use inside a transaction - it
provides USING and WITH view support for SPARQL Update - and should not
be seen otherwise.
For the journalling, if that's pulled out for now, I can get the changes
done with more degrees of freedom. Then we can put it back if need be.
Its not the journaling per se, it is the context in which it works.
Indeed DatasetGraphWithLock is really some sort of "storage DSG" (the
current DSG interface before adding Transactional) and a transactional
policy (which should be a parameter, not built in).
Andy
A corollary of all this is I will be making suggestions for RDF Patch
and DatasetChanges to have transaction boundary markers ... I'm working
on that area for $job. Turns up to be really useful building block:
* incremental backups
* geo replication
* maintaining a system-of-record
* moving live databases about
JENA-1089 (Add Transactonal to DatasetGraph) is a necessary step.
On 02/02/16 21:48, A. Soroka wrote:
Not sure what you mean by status, but I’m happy to look at any
particular problems you’re seeing. I had no intentions of taking it any
further on its own, for now. The persistent datastructure direction
seems more interesting and profitable. I would be happy to straighten
out any mistaken overruns over DSGWithLock’s semantics. Where are those
documented? (For those who missed it, the journaling dataset came in as
an early attempt to move forward with transactional in-mem storage, and
seemed to work fine when the bulk of the work for JENA-624 that I did
got merged.)
To be sure, the package is not in use in oaj.s.c.mem, which is where
the more interesting work ended up, and I cannot imagine that it is in
use by any great crowd since 3.0.1, so if you want to quash it, I’m not
going to cavil. We’ll always have the version history…
---
A. Soroka
The University of Virginia Library
On Feb 2, 2016, at 4:29 PM, Andy Seaborne <[email protected]> wrote:
Adam - what's the status of this package?
While working on JENA-1089, I found that DatasetGraphWithRecord isn't calling
up into the inherited abort(). In refactoring and tightening up around
DatasetGraphWithLock, tests detect an error. It also means changes monitoring
wasn't working.
While fixing some other timing/concurrency tests, mysterious things are
breaking in DatasetGraphWithLock, which it uses. DatasetGraphWithRecord seems
to pin down the semantics of DatasetGraphWithLock beyond the contract.
If this package isn't in use, I'd rather not spend time puzzling it all out.
Andy
