fix: support List<Float> in vector index

[szekelyszabi]

When vectors are inserted via SQL using [0.1, 0.2, ...] syntax, they are stored as ArrayList in documents. The graph building code only accepted float[] type, causing vectorNeighbors() to return empty results.

This fix adds List<?> handling in:

• LSMVectorIndex.buildGraphFromScratchWithRetry()
• ArcadePageVectorValues.getVector()

Fixes the issue where vectorNeighbors() returns empty array for SQL-inserted vectors while vectorDistance() works correctly.

[gemini-code-assist]

Summary of Changes

Hello @szekelyszabi, 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 resolves an issue where vectors inserted into the database via SQL using List<Float> syntax were not correctly processed by the vector index's graph building mechanism. Previously, the system only recognized float[] types, leading to vectorNeighbors() returning empty results for ArrayList-stored vectors. The changes introduce List<?> handling in key vector index components, ensuring that all valid vector representations are correctly indexed and searchable, thus improving the reliability of vector search functionalities.

Highlights

• Vector Index Compatibility: Enabled the vector index to correctly process vectors inserted via SQL using List<Float> syntax, which were previously stored as ArrayLists, ensuring they are properly indexed and searchable.
• Graph Building Logic Enhancement: Modified the graph building code in LSMVectorIndex and vector retrieval in ArcadePageVectorValues to accept List<?> types in addition to float[] for vector properties, resolving issues where vectorNeighbors() returned empty results for SQL-inserted vectors.

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[gemini-code-assist]

Code Review

This pull request correctly adds support for List<Float> as a vector type, which is a necessary fix for vectors inserted via SQL. The changes in ArcadePageVectorValues and LSMVectorIndex are appropriate to handle this new type.

My main feedback is regarding code duplication. The logic to convert a List to a float[] has been added to both files. This should be extracted into a single, reusable utility method to improve maintainability and ensure consistency.

I've also pointed out a minor style issue regarding missing braces in for loops, which could be improved for better code clarity and safety.

[gemini-code-assist]

For better readability and to prevent potential issues when adding more statements to the loop, it's good practice to always use braces {} for loop bodies.

Additionally, this logic for converting a List to a float[] is duplicated in LSMVectorIndex.java. It would be best to extract this into a shared static helper method to improve maintainability.

Suggested change

	for (int i = 0; i < list.size(); i++)
	vector[i] = ((Number) list.get(i)).floatValue();
	for (int i = 0; i < list.size(); i++) {
	vector[i] = ((Number) list.get(i)).floatValue();
	}

[gemini-code-assist]

This is the same duplicated logic as in ArcadePageVectorValues.java. As mentioned in the other comment, this should be extracted to a shared helper method.

For consistency and to improve readability, please add braces {} to the for loop body.

                for (int i = 0; i < list.size(); i++) {
                  vector[i] = ((Number) list.get(i)).floatValue();
                }

[lvca]

It makes sense, thanks! We should explore also using float[] natively in SQL to reduce conversion from/to List and the heavy weight of List instead of float[] in RAM