---

This section details on the original issue you should resolve

<issue_title>[MEDI] Bugs in GetPreExistingChunksIdsAsync</issue_title>
<issue_description>The way GetPreExistingChunksIdsAsync is currently implemented:

extensions/src/Libraries/Microsoft.Extensions.DataIngestion/Writers/VectorStoreWriter.cs

Lines 175 to 189 in 4d68b44

	int insertedCount;
	do
	{
	insertedCount = 0;
	await foreach (var record in _vectorStoreCollection!.GetAsync(
	filter: record => (string)record[DocumentIdName]! == document.Identifier,
	top: MaxTopCount,
	cancellationToken: cancellationToken).ConfigureAwait(false))
	{
	keys.Add(record[KeyName]!);
	insertedCount++;
	}
	}
	while (insertedCount == MaxTopCount);

We have two bugs:

• in case there are more matching records than MaxTopCount, we are going to keep fetching and adding the same records over and over. We need to provide the Skip parameter:

await foreach (var record in _vectorStoreCollection!.GetAsync(
    filter: record => (string)record[DocumentIdName]! == document.Identifier,
    top: MaxTopCount,
    options: new() { Skip = insertedCount }, // THE FIX
    cancellationToken: cancellationToken).ConfigureAwait(false))

• the loop counter should not be reset at every iteration, otherwise we might end up getting an endless loop

We need a test that reproduces the problem. If preparing MaxTopCount-many records is too complex, we can use #if !RELEASE and set the value to low number in order to make testing easier in Debug builds (our CI always runs them)

        const int MaxTopCount =
#if RELEASE
            1_000;
#else
            10; // Use smaller batch size in debug to be able to test the looping logic without needing to insert a lot of records.
#endif

</issue_description>

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