Sharding: Unsupported Features

Name: RavenDB
Author: RavenDB

A sharded RavenDB database generally provides the same services as a non-sharded database,
so existing applications, queries, subscriptions, patches, and similar operations typically require no modification.
However, some features that are supported in non-sharded databases are not yet supported in sharded databases.
The list below details these unsupported features.
In this article:

Unsupported Indexing Features

Unsupported Feature	Comment
Rolling index deployment	Rolling index deployment is not supported in a sharded database.
Loading a document that resides on another shard	Loading a document during indexing is possible only if the document resides on the shard.
Outputting map-reduce results to a collection	Outputting map-reduce index results to an artificial documents collection is not supported in a sharded database.
Custom sorters	Custom sorters are not supported in a sharded database.

Unsupported Feature	Comment
Loading a document that resides on another shard	A query can only load a document if it resides on the same shard. Loading a document that resides on a different shard will return null.
Loading a document within a Map-Reduce projection	Learn more in Loading a document within a projection.
Includes and loads are not supported in streaming queries	Learn more in Limitations when streaming query results in a sharded database.
Ordering streamed Map-Reduce results by non-reduce-key fields	Learn more in Limitations when streaming query results in a sharded database.
Querying with limit in patch/delete by query operations	Attempting to set a `limit` with PatchByQueryOperation or DeleteByQueryOperation will throw NotSupportedInShardingException.
OrderByDistance	OrderByDistance is not supported for map-reduce indexes in sharded databases. Only supported for regular (map) indexes in a sharded database.
OrderByScore	OrderByScore is not supported in a sharded database.
MoreLikeThis	Method MoreLikeThis is not supported in a sharded database.
Highlighting	Highlighting is not supported in a sharded database.
Intersection	Intersection is not supported in a sharded database.

Unsupported Feature	Comment
Move Attachments	E.g. `session.Advanced.Attachments.Move("users/1","foo","users/2","bar");` is not supported.
Copy Attachments	E.g. `session.Advanced.Attachments.Copy("users/1","foo","users/2","bar");` is not supported.
Get multiple Attachments	E.g. `session.Advanced.Attachments.Get(attachmentNames)` is not supported.
Copy Time Series	E.g. `session.Advanced.Defer(new CopyTimeSeriesCommandData(id, "Count", id2, "Count"));` is not supported.

Unsupported Feature	Comment
Create a Snapshot Backup
Restore from a Snapshot Backup

Unsupported Feature	Comment
Import from a CSV file
Import from an S3 Bucket	using GET, Studio, smuggler, import s3 dir
Import from SQL
Import from Other Databases	Importing from databases like MongoDB and CosmosDB is not supported

Unsupported Feature	Comment
Migrate from RavenDB	By POST, Studio, smuggler
Migrate from SQL DB

Unsupported Feature	Comment
Concurrent Subscriptions
Data Subscriptions Revisions Support	Subscribing to document revisions
SubscriptionCreationOptions.ChangeVector	Providing a change vector to start the processing from is not supported except for these special cases: `"LastDocument"`, `"BeginningOfTime"`, `"DoNotChange"`

Unsupported Feature	Comment
PostgreSQL
Queue ETL	Kafka ETL, RabbitMQ ETL
Queue Sink	Kafka Queue Sink, RabbitMQ Queue Sink

Unsupported Feature	Comment
JSON patch