Update Default value of Oversample for bbq

[Samiul-TheSoccerFan]

During index mapping when a dense_vector field is defined with bbq_* as index_options, the oversample value is now set to 3.0 by default.

bbq_hnsw::

PUT my-image-index { "mappings": { "properties": { "image-vector": { "type": "dense_vector", "dims": 64, "index": true, "similarity": "l2_norm", "index_options": { "type": "bbq_hnsw" } }, "file-type": { "type": "keyword" }, "title": { "type": "text" } } } } response::: { "my-image-index": { "mappings": { "properties": { "file-type": { "type": "keyword" }, "image-vector": { "type": "dense_vector", "dims": 64, "index": true, "similarity": "l2_norm", "index_options": { "type": "bbq_hnsw", "m": 16, "ef_construction": 100, "rescore_vector": { "oversample": 3 } } }, "title": { "type": "text" } } } } } 

bbq_flat::

PUT my-image-index2 { "mappings": { "properties": { "image-vector": { "type": "dense_vector", "dims": 64, "index": true, "similarity": "l2_norm", "index_options": { "type": "bbq_flat" } }, "file-type": { "type": "keyword" }, "title": { "type": "text" } } } } response:: { "my-image-index2": { "mappings": { "properties": { "file-type": { "type": "keyword" }, "image-vector": { "type": "dense_vector", "dims": 64, "index": true, "similarity": "l2_norm", "index_options": { "type": "bbq_flat", "rescore_vector": { "oversample": 3 } } }, "title": { "type": "text" } } } } } 

int8::

PUT my-image-index { "mappings": { "properties": { "image-vector": { "type": "dense_vector", "dims": 3, "index": true, "similarity": "l2_norm" }, "file-type": { "type": "keyword" }, "title": { "type": "text" } } } } response:: { "my-image-index": { "mappings": { "properties": { "file-type": { "type": "keyword" }, "image-vector": { "type": "dense_vector", "dims": 3, "index": true, "similarity": "l2_norm", "index_options": { "type": "int8_hnsw", "m": 16, "ef_construction": 100 } }, "title": { "type": "text" } } } } } 

Respect the provided value for bbq_*:

PUT my-image-index3 { "mappings": { "properties": { "image-vector": { "type": "dense_vector", "dims": 64, "index": true, "similarity": "l2_norm", "index_options": { "type": "bbq_hnsw", "rescore_vector": {"oversample": 2.0} } }, "file-type": { "type": "keyword" }, "title": { "type": "text" } } } } response { "my-image-index3": { "mappings": { "properties": { "file-type": { "type": "keyword" }, "image-vector": { "type": "dense_vector", "dims": 64, "index": true, "similarity": "l2_norm", "index_options": { "type": "bbq_hnsw", "m": 16, "ef_construction": 100, "rescore_vector": { "oversample": 2 } } }, "title": { "type": "text" } } } } } 

[Samiul-TheSoccerFan]

@benwtrent @jimczi While I work on the yaml tests, can I get a quick feedback on the current changes?

[benwtrent]

This should only happen on new indices. Please add a new index version to bar changing this on existing indices.

[elasticsearchmachine]

Hi @Samiul-TheSoccerFan, I've created a changelog YAML for you.

[elasticsearchmachine]

Pinging @elastic/es-search-relevance (Team:Search Relevance)

[Samiul-TheSoccerFan]

@benwtrent This is safe to merge or wait for @jimczi's review?

[benwtrent]

We aren't in a hurry. Let's see what @jimczi says :)

[jimczi]

LGTM, thanks @Samiul-TheSoccerFan

[jimczi]

Let's have a follow up to update the documentation @Samiul-TheSoccerFan ?

[Samiul-TheSoccerFan]

Added Documentation PR: elastic/docs-content#1290

[benwtrent]

💚 All backports created successfully

Status	Branch	Result
✅	8.19

Questions ?

Please refer to the Backport tool documentation