Add vector graph build diagnostics logging

[tae898]

I mocked what's done in https://github.com/datastax/jvector/blob/fe3f4d17a39a07b45a99403a615d8e65e9ddf8bf/jvector-examples/src/main/java/io/github/jbellis/jvector/example/benchmarks/QueryTester.java#L84 so that in arcadedb vector building we also get stats like

2026-02-01 19:10:41.421 INFO  [LSMVectorIndex] Graph build building: 957196/998480 (vector accesses=957200, heap=2121.0/4096.0MB, offheap=0.0MB, files=998.5MB [idx=998.5, graph=0.0, pq=0.0, compacted=0.0])
2026-02-01 19:10:43.444 INFO  [LSMVectorIndex] Graph build building: 957536/998480 (vector accesses=957540, heap=3125.0/4096.0MB, offheap=0.0MB, files=998.5MB [idx=998.5, graph=0.0, pq=0.0, compacted=0.0])
2026-02-01 19:10:45.464 INFO  [LSMVectorIndex] Graph build building: 957868/998480 (vector accesses=957872, heap=2630.0/4096.0MB, offheap=0.0MB, files=998.5MB [idx=998.5, graph=0.0, pq=0.0, compacted=0.0])
2026-02-01 19:10:47.491 INFO  [LSMVectorIndex] Graph build building: 958182/998480 (vector accesses=958186, heap=3229.0/4096.0MB, offheap=0.0MB, files=998.5MB [idx=998.5, graph=0.0, pq=0.0, compacted=0.0])
2026-02-01 19:10:49.583 INFO  [LSMVectorIndex] Graph build building: 958497/998480 (vector accesses=958501, heap=2602.0/4096.0MB, offheap=0.0MB, files=998.5MB [idx=998.5, graph=0.0, pq=0.0, compacted=0.0])
2026-02-01 19:10:51.639 INFO  [LSMVectorIndex] Graph build building: 958824/998480 (vector accesses=958828, heap=2322.0/4096.0MB, offheap=0.0MB, files=998.5MB [idx=998.5, graph=0.0, pq=0.0, compacted=0.0])

[tae898]

@lvca

[gemini-code-assist]

Summary of Changes

Hello @tae898, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request enhances the observability of the vector graph building process by integrating detailed diagnostic logging. It provides insights into memory consumption (heap and off-heap) and the size of various index-related files, which is crucial for performance analysis, benchmarking, and troubleshooting during vector index creation.

Highlights

• New Configuration for Diagnostic Logging: A new global configuration setting, VECTOR_INDEX_GRAPH_BUILD_DIAGNOSTICS, has been introduced. This boolean flag controls whether detailed diagnostic logging is enabled during the vector graph build process, defaulting to true.
• Enhanced Vector Graph Build Diagnostics: The LSMVectorIndex now includes functionality to capture and log comprehensive diagnostic information during graph building. This includes current heap memory usage (used/max), off-heap memory usage (direct and mapped buffers), and a breakdown of file sizes for the vector index, graph, PQ, and compacted files.
• Conditional Logging: The progress logging for vector graph builds has been updated to conditionally include these new diagnostic details. If VECTOR_INDEX_GRAPH_BUILD_DIAGNOSTICS is enabled, the log messages will show memory and file size statistics; otherwise, they will revert to the previous, simpler format.

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[mergify]

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[gemini-code-assist]

Code Review

This pull request introduces diagnostic logging for vector graph builds, which is a useful feature for troubleshooting and performance tuning. The implementation is straightforward, adding a new configuration flag and capturing memory and file size metrics during the build process. My review includes two suggestions: one to change the default value of the new configuration flag to be off by default in production, and another to simplify a utility method for better code quality.

[tae898]

2s was too much.