> ## Documentation Index
> Fetch the complete documentation index at: https://docs.pinecone.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Known limitations

> Pinecone REST API: This page describes known limitations and feature restrictions in Pinecone.

This page describes known limitations and feature restrictions in Pinecone.

## General

* [Upserts](/guides/index-data/upsert-data)
  * Pinecone is eventually consistent, so there can be a slight delay before upserted records are available to query.

    After upserting records, use the [`describe_index_stats`](/reference/api/2024-10/data-plane/describeindexstats) operation to check if the current vector count matches the number of records you expect, although this method may not work for pod-based indexes with multiple replicas.
  * Only indexes using the [dotproduct distance metric](/guides/index-data/indexing-overview#dotproduct) support querying sparse-dense vectors.

    Upserting, updating, and fetching sparse-dense vectors in indexes with a different distance metric will succeed, but querying will return an error.
  * Indexes created before February 22, 2023 do not support sparse vectors.
* [Metadata](/guides/index-data/upsert-data#upsert-with-metadata-filters)
  * Null metadata values aren't supported. Instead of setting a key to `null`, remove the key from the metadata payload.
  * Nested JSON objects are not supported.

## Serverless indexes

Serverless indexes do not support the following features:

* [Filtering index statistics by metadata](/reference/api/2024-10/data-plane/describeindexstats)
* [Private endpoints](/guides/production/configure-private-endpoints)

  * This feature is available on AWS only.