@sqlrooms/mosaic / vg / Coordinator

Class: Coordinator

A Mosaic Coordinator manages all database communication for clients and handles selection updates. The Coordinator also performs optimizations including query caching, consolidation, and pre-aggregation.

Constructors

Constructor

new Coordinator(db?, options?): Coordinator

Parameters

Parameter	Type	Description
db?	Connector	Database connector. Defaults to a web socket connection.
options?	{ logger?: Logger | null; manager?: QueryManager; cache?: boolean; consolidate?: boolean; preagg?: PreAggregateOptions; }	Coordinator options.
options.logger?	Logger | null	The logger to use, defaults to console.
options.manager?	QueryManager	The query manager to use.
options.cache?	boolean	Boolean flag to enable/disable query caching.
options.consolidate?	boolean	Boolean flag to enable/disable query consolidation.
options.preagg?	PreAggregateOptions	Options for the Pre-aggregator.

Returns

Coordinator

Properties

Property	Modifier	Type
manager	public	QueryManager
preaggregator	public	PreAggregator
clients	public	Set<MosaicClient>
filterGroups	public	Map<Selection, FilterGroupEntry>
_logger	protected	Logger

Methods

clear()

clear(options?): void

Clear the coordinator state.

Parameters

Parameter	Type	Description
options?	{ clients?: boolean; cache?: boolean; }	Options object.
options.clients?	boolean	If true, disconnect all clients.
options.cache?	boolean	If true, clear the query cache.

Returns

void

---

databaseConnector()

Call Signature

databaseConnector(): Connector | null

Get or set the database connector.

Returns

Connector | null

The current database connector.

Call Signature

databaseConnector(db): Connector

Get or set the database connector.

Parameters

Parameter	Type	Description
db	Connector	The database connector to use.

Returns

Connector

The current database connector.

---

logger()

logger(logger?): Logger

Get or set the logger.

Parameters

Parameter	Type	Description
logger?	Logger | null	The logger to use.

Returns

Logger

The current logger

---

cancel()

cancel(requests): void

Cancel previously submitted query requests. These queries will be canceled if they are queued but have not yet been submitted.

Parameters

Parameter	Type	Description
requests	QueryResult<unknown>[]	An array of query result objects, such as those returned by the query method.

Returns

void

---

exec()

exec(query, options?): QueryResult

Issue a query for which no result (return value) is needed.

Parameters

Parameter	Type	Description
query	MaybeArray<QueryType>	The query or an array of queries. Each query should be either a Query builder object or a SQL string.
options?	{ priority?: number; }	An options object.
options.priority?	number	The query priority, defaults to Priority.Normal.

Returns

QueryResult

A query result promise.

---

query()

Call Signature

query(query, options?): QueryResult<Table<TypeMap>>

Issue a query to the backing database. The submitted query may be consolidate with other queries and its results may be cached.

Parameters

Parameter	Type	Description
query	QueryType	The query as either a Query builder object or a SQL string.
options?	{[key: string]: unknown; type?: "arrow"; cache?: boolean; persist?: boolean; priority?: number; }	An options object.
options.type?	"arrow"	The query result format type.
options.cache?	boolean	If true, cache the query result client-side within the QueryManager.
options.persist?	boolean	If true, request the database server to persist a cached query server-side.
options.priority?	number	The query priority, defaults to Priority.Normal.

Returns

QueryResult<Table<TypeMap>>

A query result promise.

Call Signature

query(query, options?): QueryResult<unknown>

Issue a query to the backing database. The submitted query may be consolidate with other queries and its results may be cached.

Parameters

Parameter	Type	Description
query	QueryType	The query as either a Query builder object or a SQL string.
options?	{[key: string]: unknown; type?: "json"; cache?: boolean; persist?: boolean; priority?: number; }	An options object.
options.type?	"json"	The query result format type.
options.cache?	boolean	If true, cache the query result client-side within the QueryManager.
options.persist?	boolean	If true, request the database server to persist a cached query server-side.
options.priority?	number	The query priority, defaults to Priority.Normal.

Returns

QueryResult<unknown>

A query result promise.

---

prefetch()

Call Signature

prefetch(query, options?): QueryResult<Table<TypeMap>>

Issue a query to prefetch data for later use. The query result is cached for efficient future access.

Parameters

Parameter	Type	Description
query	QueryType	The query as either a Query builder object or a SQL string.
options?	{[key: string]: unknown; type?: "arrow"; }	An options object.
options.type?	"arrow"	The query result format type.

Returns

QueryResult<Table<TypeMap>>

A query result promise.

Call Signature

prefetch(query, options?): QueryResult<unknown>

Issue a query to prefetch data for later use. The query result is cached for efficient future access.

Parameters

Parameter	Type	Description
query	QueryType	The query as either a Query builder object or a SQL string.
options?	{[key: string]: unknown; type?: "json"; }	An options object.
options.type?	"json"	The query result format type.

Returns

QueryResult<unknown>

A query result promise.

---

updateClient()

updateClient(client, query, priority?): Promise<unknown>

Update client data by submitting the given query and returning the() data (or error) to the client.

Parameters

Parameter	Type	Description
client	MosaicClient	A Mosaic client.
query	QueryType	The data query.
priority?	number	The query priority.

Returns

Promise<unknown>

A Promise that resolves upon completion of the update.

---

requestQuery()

requestQuery(client, query?): Promise<unknown>

Issue a query request for a client. If the query is null or undefined, the client is simply updated. Otherwise updateClient is called. As a side effect, this method clears the current preaggregator state.

Parameters

Parameter	Type	Description
client	MosaicClient	The client to update.
query?	QueryType | null	The query to issue.

Returns

Promise<unknown>

---

connect()

connect(client): void

Connect a client to the coordinator. Throws an error if the client is already connected.

Parameters

Parameter	Type	Description
client	MosaicClient	The Mosaic client to connect.

Returns

void

---

disconnect()

disconnect(client): void

Disconnect a client from the coordinator. This method has no effect if the client is already disconnected.

Parameters

Parameter	Type	Description
client	MosaicClient	The Mosaic client to disconnect.

Returns

void