Handle analytical mode in community_detection during parallel changes

Darych commented 8 months ago

Description

NB: PR taken over by @antepusic; connected with https://github.com/memgraph/memgraph/pull/1395

Since there are no ACID guarantees in analytical storage mode, the graph may get modified by parallel transactions while the user’s query is running. Query procedures and functions that return graph elements (nodes and relationships) should be robust to the deletion of graph elements, and this PR aims to fix that.

This PR contains changes to query modules that ensure the intended behavior:

Query modules written with the C and C++ APIs check the existence of values that may contain graph elements before returning them (Python API query modules do this under the hood)

Merge commit message:

Add proper handling of deleted return values for query procedures and functions ran in analytical mode

Pull request type

[x] Bugfix

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Reviewer checklist (the reviewer checks this part)

Module/Algorithm

[ ] Core algorithm/module implementation
[ ] Query module implementation
[ ] Unit tests
[ ] End-to-end tests
[ ] Code documentation
[ ] README short description
[ ] Documentation on memgraph/docs
[ ] Update GQLALchemy signatures in query builder using query module signature generator

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as51340 commented 7 months ago

And you have build errors, please take care about that before requesting review again. For next time tip: it is better to request review after build errors are fixed since it gives reviewer more confidence that hey this is good and meaningful fix without negative impact on the rest of the system

Darych commented 7 months ago

My initial idea was to make body of GetInnerNodeIdOpt a default implementation for GetInnerNodeId, so we will have just one implementation. I mentioned about this HERE Currently. we have 2 implementations and users should think which one they need to use in their modules. @antoniofilipovic what do you think?