Huge syncstore file ... how to reduce the size of the syncstore file on my computer

The syncstore file is about 135 gigs … My computer is running out of space … is it normal to have such a large syncsore and is there a way to reduce its size…

Wow - how large is the database being sync’d?
What sync method are you using?

fwiw Bonjour sync is direct device<>device, there is no syncstore
With an iCloud (Cloudkit) syncstore, there is no local disk space impact
My 20GB database uses a 15GB syncstore in the cloud