v25.4.0-preview1 (mutations pipeline)

[matthewmcneely]

This preview release showcases the per-predicate mutation pipeline feature. This feature increases mutation performance for write heavy processes under certain conditions. See the PR for more information.

The image can be pulled from our "custom" Docker repo via dgraph/dgraph-custom:v25.4.0-preview1

IMPORTANT
A feature flag enables this functionality: --feature-flags="mutations-pipeline-threshold=N" — N=0 disables the pipeline entirely (legacy path), N=1 always uses it, N>1 only routes mutations with ≥ N edges to it. The pipeline pays a per-predicate goroutine spin-up cost, so tiny mutations are slightly slower on it; bulk multi-predicate mutations are faster (crossover ≈ 100 edges in in-process benches; live-loading the 1M dataset is ~1.5× faster end-to-end at threshold=1 vs. legacy). As shipped, the current setting is 1, meaning always ON. It's recommended that for your testing you set the value to somewhere around 100.

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This discussion was created from the release v25.4.0-preview1.

[rahst12]

I'm going to try to get this built and into a docker image to test. Looking forward to your thoughts on this comment: #9467 (comment)

Looks like the negative effects of flag can be mitigated by proportionally providing the 64 goroutines the predicate batches, with the scope of the previous math. This improvement feels like a great preview2!