Revert erroneous async -> sync

Summary: This differential reverts mistake I made when landing GlobalDBSingleton diff stack. Context: https://phab.comm.dev/D5233 (last comment)

Test Plan: Same as for https://phab.comm.dev/D5233

Reviewers: tomek

Reviewed By: tomek

Subscribers: ashoat, atul, abosh

Differential Revision: https://phab.comm.dev/D5326