Collections Overview

Your data is organized into collections. When you create an app, Fusion automatically creates a collection with the same name. You can create additional collections in any app.

A primary collection contains the data that your users will search. Every primary collection is associated with a set of auxiliary collections that contain related data, such as signals, aggregations, and more.

Under the hood, a Fusion collection is a distributed index in Solr, defined by a named configuration stored in ZooKeeper, with these properties:

  • Number of shards

    Documents are distributed across this number of partitions.

  • Document routing strategy

    How documents are assigned to shards.

  • Replication factor

    How many copies of each document in the collection.

  • Replica placement strategy

    Where to place replicas in the cluster.

If your data is already stored in a Solr instance or cluster, you can manage this collection in Fusion by creating a Fusion collection that imports the existing Solr collection. See Installation with an existing Solr instance or cluster.

Collection names are case-insensitive, but Fusion preserves case when displaying collection names.

Auxiliary Collections

Every primary collection is associated with a set of auxiliary collections that contain related data, such as signals, aggregations, and more.

Some auxiliary collections are created for every primary collection. Others are created only for the app’s default collection, one per app.

Auxiliary collections are described below:


1 per app


A collection of documents to use for rewriting queries, optimized for high-volume traffic. These documents originate from the _query_rewrite_staging collection. Certain Fusion AI query pipeline stages read from this collection:

1 per app


A collection of documents created by the Rules Editor or by certain Fusion AI jobs, not optimized for production traffic.

Documents move from this collection to the _query_rewrite collection as follows:

  • Job output documents with high confidence contain a review=auto field and are moved to the _query_rewrite collection automatically.

  • Job output documents with low confidence contain a review=pending field. When these are approved by a Fusion user, Fusion copies them to the _query_rewrite collection.

1 per app


A search query logs and signals collection.

1 per collection


A collection for aggregated signals.

1 per collection


A collection of data to support App Studio’s social features, such as user-generated tags, bookmarks, comments, ratings, and so on.

1 per app

Do not create primary collections with names that end in the suffixes above; these are reserved for Fusion auxiliary collections, which are created and managed by Fusion directly.

Fusion maintains a set of Solr collections that store Fusion’s own log files and other internal information. These are called System Collections, described below.

Do not create primary collections named "logs" or beginning with "system_". These names are reserved for Fusion system collections.

Fusion uses ZooKeeper to register information about all collections, and the Fusion components and services related to a collection. The Fusion components associated with a collection include:

  • Datasources

  • Pipelines

  • Profiles

  • Signals and aggregations

  • Analytics dashboards

System Collections

Fusion automatically creates some collections that are used for internal purposes and shared across all apps:

  • system_autocomplete store the content that the Fusion UI displays when you use the search bar.

  • system_blobs stores blobs in Solr. This is used to store model files for the NLP components and other binary files used by Fusion components.

  • system_history keeps a record of configuration changes, start and stop times for services and experiments, and more.

  • system_jobs_history keeps a record of Fusion jobs, including start/stop times and status.

  • system_logs stores parsed Java logs from the REST API, connectors-classic component, and other parts of Fusion, like proxy, connectors-rpc, and appkit app insights. It also includes http logs and optional gc logs (off by default in Fusion 4.1). Prior to Fusion version 4.1, Java logs were stored in the logs collection and HTTP requests were stored in the audit_logs collection.

  • system_messages is used by Fusion’s messaging services.

  • system_monitor stores metrics about Fusion hosts and services. See System Metrics and the DevOps Center.

Collection Configuration Properties

Collections have three properties that you can configure only when you are creating a collection using the Collections API.

Property Description Default behavior


The signals property determines whether to create auxiliary collections with suffixes _signals and _signals_aggr.

When you create a collection in the Fusion UI, signals defaults to true.
When you create a collection using the Fusion API, this property defaults to false.


The searchLogs property determines whether to create an auxiliary search query logs collection with suffix _logs.

When you create a collection in the Fusion UI, this property defaults to true.
When you create a collection using the Fusion API, this property defaults to false.


When dynamicSchema is true, Fusion and Solr use schemaless mode to administer search and indexing over that collection.**

Property dynamicSchema always defaults to false.

*Signals are events with timestamps that can be used to improve search results. For more information about signals in Fusion, see Signals in the Fusion AI documentation.

**In schemaless mode, if a document contains a field not currently in the Solr schema, Solr processes the field value to determine what the field type should be defined as, and then adds a new field to the schema with the field name and field type. This behavior can be convenient during preliminary application development, but it is rarely appropriate in a production environment.

Using profiles to associate collections with pipelines

Index pipelines and query pipelines are not connected to a specific collection by default. Index profiles and query profiles are configurations that create consistent endpoints for indexing and querying, each with a specific pipeline and collection.

Field Editor UI

The Fusion UI includes a space under Collections to edit Fields. Descriptions for these fields can be found in the Field Type Definitions page of the Solr Reference Guide.

Field options displayed in the UI include:

  • Dynamic checkbox (cannot change via UI)

  • Field Name (cannot change via UI)

  • Field Type (a preset value is shown that can be changed using edit mode)

  • Checkboxes for Indexed, Stored, Multivalued, Required

  • Text field to enter a Default Value

  • Copy Fields uses the plus sign to add rows (static can copy to raw_content or text; dynamic can copy to any raw_content/text or any other dynamic field)

  • Advanced toggles checkboxes for Doc Values, Omit Norms, Omit Positions, Omit term freq and positions, Term Vectors, Term Positions, Term Offsets