Rewrite local vocab entries and blank nodes for DeltaTriples

[joka921]

Each DeltaTriples object has exactly one local vocab and one blank node manager. When inserted triples contain local vocab IDs or blank node IDs, these are rewritten for that local vocab and blank node manager. Different local vocab entries referring to the same string are rewritten to the same new local vocab ID. Similarly, different occurrences of the same blank node are rewritten to the same new blank node ID. The rewriting also ensures that local vocab entries or blank nodes that were created merely during the evaluation of the WHERE clause of an insert operation, but do not end up in one of the resulting triples, do not become part of the local vocab or blank nodes of the DeltaTriples object.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 89.04%. Comparing base (2ccfb50) to head (f44ee5a).
Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1580   +/-   ##
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  Coverage   89.04%   89.04%           
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  Files         368      368           
  Lines       33972    34018   +46     
  Branches     3839     3846    +7     
=======================================
+ Hits        30249    30293   +44     
- Misses       2471     2472    +1     
- Partials     1252     1253    +1     

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[hannahbast]

1-1 with Johannes, this looks great.

I will revise the comments and test it, then let's see

[sparql-conformance]

Conformance check passed ✅

No test result changes.

Details: https://qlever.cs.uni-freiburg.de/sparql-conformance-ui?cur=88f0ef7a918120eb938c5bf4a9a512b9c92a683f&prev=2ccfb50e6b332d70bb277280976cf116d67c147b

[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[hannahbast]

Looks great now from my side

[Qup42]

To evaluate the triple set for an update it is sufficient to calculate this in the ID space. I also stumbled upon this problem. I have one question about the behaviour of the PR:

• Triples with IDs from a LocalVocab can be inserted into DeltaTriples. The DeltaTriples then takes care of transferring the LocalVocab IDs to its LocalVocab. The only thing the caller has to take of is ensure that the LocalVocab lives long enough. Is that correct?
• If the result is fully materialized the LocalVocab lives as long as the Result. How long are the LocalVocabs valid for Results that are not fully materialized?

[hannahbast]

@Qup42 The idea is to potentially maintain multiple DeltaTripels objects, rereferenced via shared pointers. Whenever new delta triples come in, a copy of the most recent object is created and the triples are added to that object. Each query uses the most recent DeltaTriples object at the time of the query. A DeltaTripels object lives as long as it is referenced by at least one query that is still running (or a cache entry in case we still have those, but no sure about that). A DeltaTriples object is deleted when it is no longer referenced (typical shared pointer semantics). The most recent DeltaTriples object is never deleted.

Does this answer your questions?

[Qup42]

That does clear up the bigger picture of this PR. Johannes and I cleared up the questions in private. The two aspects are relevant to my next PR.