Overview

Indexing, or property indexing, is a technique used in Ultipa to speed up query performance by creating indexes on specific properties of nodes and edges. This allows the database to quickly locate and retrieve data based on indexed properties. Indexes are particularly beneficial for large datasets, as they optimize the filtering of specific property values without needing to scan the entire graph.

Index Types

Ultipa supports single index on one property and composite index which involve multiple properties from a schema.

Showing Indexes

To retrieve information about indexes in the current graphset:

// Shows all indexes
show().index() 

// Shows all node indexes
show().node_index()

// Shows all edge indexes
show().edge_index()

The information about indexes is organized into tables _nodeIndex and _edgeIndex. Each table includes fields that provide essential details about each index:

Creating Indexes

You can create one or more indexes using a single create() statement. Each index is specified by chaining a node_index() or edge_index() method. Note that each property can only have one single index. The index creation runs as a job, you may run show().job(<id?>) afterward to verify the success of the creation.

System properties in Ultipa are inherently optimized for query performance and have built-in efficiencies. However, they do not support additional indexing.

create()
  .node_index(@<schema>.<property>(<length?>), "<indexName>")
  .edge_index(@<schema>.<property>(<length?>), "<indexName>")
  .node_index(@<schema>(<property1>(<length1?>), <property2>(<length2?>), ...), "<indexName>")
  .edge_index(@<schema>(<property1>(<length1?>), <property2>(<length2?>), ...), "<indexName>")
  ...

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To create single index balance for node property @card.balance:

create().node_index(@card.balance, "balance")

To create single index cName for edge property @card.name (string type), restricting the maximum search string length as 10:

create().edge_index(@card.name(10), "cName")

To create composite index transAmountNotes for properties amount and notes (text type, restricting the maximum search string length as 10) for @transfer edges:

create().edge_index(@transfer(amount, notes(10)), "transAmountNotes")

To create multiple indexes:

create()
  .node_index(@card.balance, "balance")
  .edge_index(@transfer(amount, notes(10)), "transAmountNotes")

Dropping Indexes

You can drop one or more indexes using a single drop() statement. Each index is specified by chaining a node_index() or edge_index() method. Dropping an index does not affect the actual property values stored in shards. However, deleting a property will automatically remove its associated indexes.

To drop the node index balance:

drop().node_index("balance")

To drop the edge index transAmountNotes:

drop().edge_index("transAmountNotes")

To drop multiple indexes:

drop().node_index("balance").edge_index("transAmountNotes")

Using Indexes

Indexes are automatically applied when the corresponding properties are used in query filters, without the need for explicit declarations.

Leftmost Prefix Rule

The order of properties in a composite index matters — queries that match the leftmost properties of the index (i.e., the first property or the first few properties in the defined order) will benefit from the index.

For example:

create().node_index(@user(name(10),age), 'name_age')

• find().nodes({@user.name == "Kavi" && @user.age > 20}) uses the index.
• find().nodes({@user.name == "Kavi"}) uses the index.
• find().nodes({@user.age > 20}) doesn't use the index.
• find().nodes({@user.name == "Kavi" && @user.age > 20 && @user.grade == 7}) uses the index, meanwhile it contains the filtering for the @user.grade property which lacks an index.

String Length Limitation

For indexes with string or text properties, ensure the filter string length does not exceed the defined limit.

For example:

create().edge_index(@user.name(8), "Username")

The query below won't utilize the Username index as the specified string exceeds the 8-character limit:

find().nodes({@user.name == "Aventurine"}) as n return n