SAS/ACCESS^® software creates representations of the MongoDB collection within the schema when a connection is made to the database. For collections that have array fields or sub-collections, SAS generates a flat table. A flat table includes columns for all fields in the original document, including those fields that are specified within a substructure. Each document is shown as a row in the table. The flat tables can get large, such that they exceed the MongoDB 16-MB limit.  

Click the Hot Fix tab in this note to access the hot fix for this issue.

After you apply this hot fix, the creation of flat tables is no longer done by default. Instead, the following behavior occurs:

• Creating a new schema during the initial scan results in a schema being created with no flat tables.
• Performing an execute(refresh) by libref; on an existing schema results in no flat tables being created in the updated schema.
• Performing an execute(refresh(+flat)) by libref; on an existing schema results in the updated schema now having the flat tables.
• Performing an execute(refresh(-flat)) by libref; on an existing schema results in the updated schema now not having any flat tables.

With SAS^® Viya^®, the refresh can include other options while including the +flat or the -flat option. For reference, see the Variations of the REFRESH Command for Schema Updates table in the Working with Schemas for MongoDB Data in SAS^® Viya^® Platform Programming Documentation.

Operating System and Release Information

A fix for this issue for SAS Threaded Kernel Extension for MongoDB 9.42 is available at: