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@@ -72,7 +72,7 @@ Response:
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The `shard_size` parameter limits how many top-scoring documents are collected in the sample processed on each shard.
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The default value is 100.
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-=== Controlling diversity
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+==== Controlling diversity
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Optionally, you can use the `field` or `script` and `max_docs_per_value` settings to control the maximum number of documents collected on any one shard which share a common value.
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The choice of value (e.g. `author`) is loaded from a regular `field` or derived dynamically by a `script`.
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@@ -139,16 +139,16 @@ The default setting is to use `global_ordinals` if this information is available
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The `bytes_hash` setting may prove faster in some cases but introduces the possibility of false positives in de-duplication logic due to the possibility of hash collisions.
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Please note that Elasticsearch will ignore the choice of execution hint if it is not applicable and that there is no backward compatibility guarantee on these hints.
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-=== Limitations
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+==== Limitations
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-==== Cannot be nested under `breadth_first` aggregations
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+===== Cannot be nested under `breadth_first` aggregations
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Being a quality-based filter the sampler aggregation needs access to the relevance score produced for each document.
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It therefore cannot be nested under a `terms` aggregation which has the `collect_mode` switched from the default `depth_first` mode to `breadth_first` as this discards scores.
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In this situation an error will be thrown.
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-==== Limited de-dup logic.
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+===== Limited de-dup logic.
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The de-duplication logic in the diversify settings applies only at a shard level so will not apply across shards.
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-==== No specialized syntax for geo/date fields
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+===== No specialized syntax for geo/date fields
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Currently the syntax for defining the diversifying values is defined by a choice of `field` or `script` - there is no added syntactical sugar for expressing geo or date units such as "1w" (1 week).
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This support may be added in a later release and users will currently have to create these sorts of values using a script.
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Zachary Tong