Not when threading is disabled, as it is in this project.

Sure, but single threading isn't an inherent part of sqlite as OP implies.

> SQlite3 automatically means:

...

> - No parallel reads from multiple threads

It is not disabled, as you think. It is secured by the internal code in Pack. Almost all parts of Pack are multithreaded.

it’s not safe to disable SQLite’s thread safety as you do here: https://github.com/PackOrganization/Pack/blob/main/Libraries... and then do your own locking. You attempt to pass the flag at open time to enable serialized mode, however quoting the SQLite docs for the build flag you set:

  Note that when SQLite is compiled with SQLITE_THREADSAFE=0, the code to make SQLite threadsafe is omitted from the build. When this occurs, it is impossible to change the threading mode at start-time or run-time.

SQLite’s APIs are often hazardous in these ways, it really should be erroring rather than silently ignoring the fullmutex flag, but alas.