[Question]: How to get all nodes from vectorstoreindex

[Prem-Nitin]

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Question

I am using chroma vector db to store my nodes. Now how do I retrieve all the nodes from the created index.

[dosubot[bot]]

To retrieve all nodes from your Chroma vector database index, you can modify the ChromaVectorStore class to include a method that fetches all nodes. Here's how you can add such a method:

class ChromaVectorStore(BasePydanticVectorStore):
    ...
    def retrieve_all_nodes(self) -> VectorStoreQueryResult:
        """Retrieve all nodes from the Chroma vector store."""
        very_high_limit = 1000000  # Adjust based on your collection size
        return self._get(limit=very_high_limit, where={})

This method uses a very high limit to ensure all nodes are retrieved, with an empty dictionary passed to the where argument to apply no filters. Adjust the very_high_limit as necessary, considering the size of your dataset. For large datasets, consider implementing pagination or chunked retrieval to manage performance and resource usage effectively.

This approach assumes direct access to modify the ChromaVectorStore class. If you're working with a large number of nodes, keep in mind the efficiency and feasibility of this operation, as fetching a large dataset in a single call might be resource-intensive.

#### Details

**Sources** - [Obtain nodes from VectorStoreIndex](https://github.com/run-llama/llama_index/discussions/8930) - [How to get nodes once stored in ChromaVectorStore or OpenSerachVectorStore.](https://github.com/run-llama/llama_index/discussions/11058) - [[Question]: How can I get nodes from VectorStoreIndex ?](https://github.com/run-llama/llama_index/issues/13103) - [[Question]: Get all nodes on an index(VectorStoreIndex)](https://github.com/run-llama/llama_index/issues/9206) - [[Question]: I need to get nodes on an index which is of instance VectorStoreIndex. can you provide any solution using the VectorStoreIndex methods?](https://github.com/run-llama/llama_index/issues/9208) - [llama-index-integrations/vector_stores/llama-index-vector-stores-chroma/llama_index/vector_stores/chroma/base.py](https://github.com/run-llama/llama_index/blob/main/llama-index-integrations/vector_stores/llama-index-vector-stores-chroma/llama_index/vector_stores/chroma/base.py) - [llama-index-legacy/llama_index/legacy/indices/vector_store/base.py](https://github.com/run-llama/llama_index/blob/main/llama-index-legacy/llama_index/legacy/indices/vector_store/base.py) - [llama-index-core/llama_index/core/indices/vector_store/retrievers/retriever.py](https://github.com/run-llama/llama_index/blob/main/llama-index-core/llama_index/core/indices/vector_store/retrievers/retriever.py) - [llama-index-legacy/llama_index/legacy/indices/multi_modal/base.py](https://github.com/run-llama/llama_index/blob/main/llama-index-legacy/llama_index/legacy/indices/multi_modal/base.py) - [llama-index-core/llama_index/core/indices/multi_modal/retriever.py](https://github.com/run-llama/llama_index/blob/main/llama-index-core/llama_index/core/indices/multi_modal/retriever.py) - [llama-index-core/llama_index/core/indices/vector_store/base.py](https://github.com/run-llama/llama_index/blob/main/llama-index-core/llama_index/core/indices/vector_store/base.py) - [llama-index-core/llama_index/core/indices/vector_store/retrievers/__init__.py](https://github.com/run-llama/llama_index/blob/main/llama-index-core/llama_index/core/indices/vector_store/retrievers/__init__.py)
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[terilias]

Hello, Normally, you can retrieve the nodes of your index using this method (at least, this is how I've been doing it. If anyone from the LlamaIndex team is available, it would be great to get confirmation on this approach). Also check this approach.

# How to see the nodes of the index 

# Get the relative dictionary.
ref_doc_info = index.ref_doc_info

doc_count = 0
node_count = 0
# Iterate over the documents and their nodes: each documents has been broken into one or more nodes.
for doc_id, doc_info in ref_doc_info.items():

    print("Document ID:", doc_id)
    #print("Document's content:", documents)
    doc_count = doc_count + 1
    nodes = doc_info.node_ids
    print("Number of nodes:", len(nodes))

    for node in nodes:
        node_count = node_count + 1
        print("Node:", node)
        print('-------')

print('======================================')
print('Total number of documents:', doc_count)
print('Total number of nodes:', node_count)`

But this method is not working with Chroma index yet. If you try to run this code you will get a NotImplementedError: Vector store integrations that store text in the vector store are not supported by ref_doc_info yet. So for this reason my apporach is to create the nodes in the same time when I create the index, and keep them in a pickle file. And whenever I need to update the index, I perform the update on the pickle file too (by loading the nodes list from the pickle file, then apply the changes and save them back to the disk). If anyone has a better approach to suggest it would be helpful.

[logan-markewich]

I would just retrieve with a top k of 10000, or use the actual chroma client

[VaradDeshmukh97]

I would just retrieve with a top k of 10000, or use the actual chroma client

Using Chroma doesn't allow us to retrieve the nodes, because the docstore is empty. This is problematic especially when we intend to use a bm25 retriever, because it needs the nodes to initialize. So I had to revert back to Simple VectorStoreIndex.

[Timotheevin]

I am also trying to use a BM25 retriever on a ChromaVectorStore. I managed to extract the nodes using these lines :

vector_store = ChromaVectorStore(chroma_collection=vector_store.collection)
index = VectorStoreIndex.from_vector_store(vector_store, embed_model=embeddings)
nodes = index.storage_context.vector_store._get(limit=sys.maxsize, where={}).nodes

The only issue is that I think there is a mistake in the get function as it only takes the first character of the id instead of the entire string. Therefore you can't have two nodes that begin with an 'a' for instance. Hope they fix that soon. (Issue #14355)