A performance regression for operations in multi-document transactions was introduced by both SERVER-35789 and SERVER-36005. These changes require all callers of IndexCatalogEntry::isReady to confirm that the catalog metadata on-disk is consistent with the in-memory version. This method is called any time the query system uses, or considers using any single index.

In certain bulk update workloads, the effects of both commits showed a combined regression of up to a 38% decrease in write throughput compared to previous test runs.

This was previously a DEV invariant that was only executed in Debug builds. It used to be a fairly inexpensive call, but it's prevalence in code accompanied with its performance hit caused quite a significant regression.