SQLite Forum

DB read fails while doing parallel bulk DB updates
> Is there a way to run update queries while creating indexes?

You can put each table in a separate database file.

Threads that need to see both tables can open the first database file,
then ATTACH the second.  You can still do JOINs across multiple tables,
even if they are in separate database files.  But if two database files
are involved, you can be doing a CREATE INDEX on one, while doing a
simultaneous UPDATE on the other.

You can try that.  But in your case, I'm not certain if it will help. It
might be that the limiting factor for you is not the number of parallel threads,
but rather write bandwidth of your eMMC storage.  You can create all the
parallel threads you want, but that is not going to make your eMMC go
any faster.  It is still, worth a try, though.