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https://issues.apache.org/jira/browse/JENA-189?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13818827#comment-13818827
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Claude Warren commented on JENA-189:
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I have not looked at SDB nor have I looked at the TDB code. I have looked at
various in-memory and the early file based systems. My comments are somewhat
SQL centric as I used the terms from SQL database transactions because 1)
relational databases have a lot of experience with transactions and how they
are used in production environments; and 2) the terms are mostly understood or
easy to research.
My comments on iterators come from the iterator documentation and the way in
which in memory iterators work. It sounds like TBD defines the collection
being iterated over as the items within the transaction, not necessarily the
graph/model as a whole. This is basically what I wanted to see, perhaps what
we need here is a clarification to the documentation describing what the
iterators are iterating over. Q: will TDB ever throw a concurrent modification
error on an iterator?
Other:
Indeed locking a subgraph does not guarantee that you will be able to stabilise
the query results for all queries, however, I think that it would be useful for
a fairly large subset of queries. Since pattern negation necessarily opens the
door for non-terminating queries any query with pattern negation would probably
be excluded from the set of queries that this would be beneficial for.
> Jena 3 / technical
> ------------------
>
> Key: JENA-189
> URL: https://issues.apache.org/jira/browse/JENA-189
> Project: Apache Jena
> Issue Type: Brainstorming
> Reporter: Andy Seaborne
> Attachments: IteratorLockandTransactionsinJena3.pdf
>
>
> This is a JIRA to discuss and collect technical changes to Jena that would
> warrant a "Jena3" whether an incompatible change or just sufficient changes
> to mean bumping the major version number is best.
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