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The names of the collections that exist.

public IAsyncEnumerable<string> ListCollectionNamesAsync(CancellationToken cancellationToken = default)

Parameters — cancellationToken is checked before each name.

Returns — IAsyncEnumerable<string>: one name per collection this store has handed out that has been ensured or written to, and not deleted since. No order is promised.

Exceptions — OperationCanceledException when cancellationToken is cancelled while the names are enumerated.

Example — a collection that was only asked for is not listed.

using Lodestar.Extensions.VectorData;
using Microsoft.Extensions.VectorData;

static async Task<string> ListAsync()
{
    using var store = new LodestarVectorStore();
    await store.GetCollection<string, Note>("written").UpsertAsync(
        new Note { Id = "a", Text = "a note", Embedding = new float[] { 1f, 0f, 0f } });
    await store.GetCollection<string, Note>("ensured").EnsureCollectionExistsAsync();
    store.GetCollection<string, Note>("requested");

    List<string> names = await store.ListCollectionNamesAsync().ToListAsync();
    names.Sort(StringComparer.Ordinal);
    return string.Join(",", names);
}

string listed = ListAsync().GetAwaiter().GetResult();  // => ensured,written

Remarks — the enumeration is not asynchronous work. The names are already in memory, so nothing is awaited between them; the method is an iterator because the abstraction returns one, and it does not insert a Task.Yield to look otherwise. Like every iterator, it runs nothing until it is enumerated.

A collection deleted through LodestarVectorStore.EnsureCollectionDeletedAsync drops out of the listing and stays retrievable by name, empty; writing to it lists it again.

Applies to — net10.0, netstandard2.0.

See also — LodestarVectorStore.CollectionExistsAsync, LodestarVectorStore.