Well, the point is that shared-cache is frowned upon, and kinda deprecated, except on very low resources devices, which is precisely not the case of wanting to use it on large multi-core desktop machines. Except shared-cache was the only known way to have separate SQLite connections sharing the same in-memory DB within the bounds of a single process, allowing concurrent access to the same DB from several threads. Until MemDB VFS. But then you say they end up being the same code... that's confusing. Shared-cache implies normal Journal mode, with readers blocking writers, and the writer blocking readers. WAL not supported. While nothing prevents in theory a VFS from supporting WAL-mode, as long as that VFS supports SHM, which it can if that VFS is in-memory. Thus my question whether MemDB VFS supports WAL-mode for true MVCC. Hopefully everything will be clearer soon. --DD