What is the size limit of a cosmosdb item?

Question

I've been looking for a authoritative source of azure cosmosdb limits by I can't find one. In particular, I need to know the size limits for a individual item.

Speaking

Answer 1

The maximum size of a document today is 2MB.

https://learn.microsoft.com/en-us/azure/cosmos-db/documentdb-resources#documents

Duralumin

is there a way to know the size of your document? – Protrude

It is actually a size of serialized JSON – Jackfish

@Jackfish But 2mb gzipped? With no whitespace? UTF-8? etc. – Expressionism

Possible answer: "If you get (or query) a document, you can then look at the headers that come back, specifically x-ms-resource-usage, which will contain a documentsSize attribute (representing a document's size in kb)." – Expressionism

Documentation has been updated and now, quotas can be found here: learn.microsoft.com/en-us/azure/cosmos-db/… – Limiter

Answer 2

So this is one of those things that always annoys me about documentation.
Sure it's 2MB, but by who's measuring stick.

TLDR: Between 2,090,014 and 2,100,014 when Encoding.UTF8.GetByteCount(doc) or Encoding.ASCII.GetByteCount(doc)

To get there I set up the following code:

 for (int i = 10; i < 10000; i++)
        {
            var docItem = new TestItem(new string('A', i * 10000));
            string doc = JsonConvert.SerializeObject(docItem);
            log.LogInformation(" ");
            log.LogInformation(" -------------------------------------------------------------------------------------------------------------------------------------");
            log.LogInformation($" -------------------------------------------------        Doc Size = {i*10000 }       --------------------------------------------------");
            log.LogInformation(" -------------------------------------------------------------------------------------------------------------------------------------");
            
            log.LogWarning($"UTF7 - {Encoding.UTF7.GetByteCount(doc)}");
            log.LogWarning($"UTF8 - {Encoding.UTF8.GetByteCount(doc)}");
            log.LogWarning($"UTF32 - {Encoding.UTF32.GetByteCount(doc)}");
            log.LogWarning($"Unicode - {Encoding.Unicode.GetByteCount(doc)}");
            log.LogWarning($"Ascii - {Encoding.ASCII.GetByteCount(doc)}");
            log.LogInformation(" -------------------------------------------------------------------------------------------------------------------------------------");
            log.LogWarning($"UTF7 - {ASCIIEncoding.UTF7.GetByteCount(doc)}");
            log.LogWarning($"UTF8 - {ASCIIEncoding.UTF8.GetByteCount(doc)}");
            log.LogWarning($"UTF32 - {ASCIIEncoding.UTF32.GetByteCount(doc)}");
            log.LogWarning($"Unicode - {ASCIIEncoding.Unicode.GetByteCount(doc)}");
            log.LogWarning($"Ascii - {ASCIIEncoding.ASCII.GetByteCount(doc)}");
            try
            {
                await cosmosStore.CreateDocumentAsync(docItem);
            }
            catch (Exception e)
            {
                log.LogWarning(e.Message + "Caught");
            }
        }

And here's where it broke:

Composed

Answer 3

Update: increasing the max size to 16 MB is now possible. https://devblogs.microsoft.com/cosmosdb/larger-document-sizes-unique-index-improvements-expr-support-in-azure-cosmos-db-api-for-mongodb/

Gasconade

This is only for the mongo api – Navel

Answer 4

The max allowable document size is 2 MB. This is fixed for Azure Cosmos DB for NOSQL API account

If it Exceeds you face 413 error --> 413 Entity too large  The document size in the request exceeded the allowable document size for a request.

If your Environment is already in Production we still suggest reducing the document size as a solution. You can Reduce the document size/ Re model your data

More Info: Azure Cosmos DB service quotas | Microsoft Learn

https://learn.microsoft.com/en-us/azure/cosmos-db/concepts-limits#per-item-limits

Additional Information:

For Azure Cosmos DB for API for MongoDB If your Azure Cosmos DB account is Mongo DB API , the limit is 2 MB but

• There is a preview feature and please be noted that this is not recommended for prod environment: There is a preview feature to set 16MB limit per document in API for MongoDB.

Ref:

• https://azure.microsoft.com/en-us/updates/public-preview-16mb-limit-per-document-in-api-for-mongodb/

• https://learn.microsoft.com/en-us/azure/cosmos-db/mongodb/feature-support-42#data-types

However, it’s in preview and not recommended for Production environments. There’s no ETA when it will be GA.

Cher