Add support for relation evaluation similar to expression evaluation

eclipse-viatra-bot commented 3 months ago

| --- | --- | | Bugzilla Link | 580745 | | Status | UNCONFIRMED | | Importance | P3 normal | | Reported | Sep 16, 2022 06:49 EDT | | Modified | Nov 29, 2022 06:58 EDT | | Version | 2.8.0 | | See also | Gerrit change 195861, Git commit 643edd93, Gerrit change 196456, Git commit 4c7f4ade, Gerrit change 196471, Git commit d3f7ea9a, Gerrit change 197358 | | Reporter | Tamas Szabo |

Description

Viatra already supports the ExpressionEvaluation constraint which can be used to plug-in arbitrary Java code (meeting certain assumptions) that computes an output value given an input tuple. The ask here is to support this kind of extensibility on the relation level, as well. The idea is to add a relation evaluation constraint which can take an arbitrary number of input relations and produce a single output relation. High-level requirements are as follows:

The evaluation logic is arbitrary Java code that can be plugged in to the evaluator similar to how the expression evaluation does that.
The relation evaluator is envisioned as a non-incremental "island" in the computation network. It takes entire input relations and produces entire output relation. It is the computation network's responsibility to incrementalize the output by computing the output delta compared to the previously computed results.
Given that the relation evaluation takes entire input relations, it is infeasible to call it again and again every time the input relation changes by just one tuple. Ideally, the input changes shall be delayed until we can collect all input changes in the current update cycle and then send all of them in batch-style to the relation evaluator.

eclipse-viatra-bot commented 3 months ago

Sep 16, 2022 07:06

New Gerrit change created: https://git.eclipse.org/r/c/viatra/org.eclipse.viatra/+/195861

eclipse-viatra-bot commented 3 months ago

Sep 26, 2022 04:17

Gerrit change https://git.eclipse.org/r/c/viatra/org.eclipse.viatra/+/195861 was merged to [master].\ Commit: http://git.eclipse.org/c/viatra/org.eclipse.viatra.git/commit/?id=643edd93063fe19e2028cad0227a0047489cd74d

eclipse-viatra-bot commented 3 months ago

Oct 21, 2022 07:31

New Gerrit change created: https://git.eclipse.org/r/c/viatra/org.eclipse.viatra/+/196456

eclipse-viatra-bot commented 3 months ago

Oct 21, 2022 14:09

Gerrit change https://git.eclipse.org/r/c/viatra/org.eclipse.viatra/+/196456 was merged to [master].\ Commit: http://git.eclipse.org/c/viatra/org.eclipse.viatra.git/commit/?id=4c7f4ade7917a6333274ab0f99a9a37980b10d26