go version)?$ go version go version go1.16.4 darwin/amd6
Yes.
Hi,
I’m new to BadgerDB. As it’s not mentioned in the documentation, is it possible or recommended to open multiple badger.db instances in multiple go routines? Can read-write transactions from different badger.db instances work properly with each other?
Thank you for your help in advance.
Jonathan Xu
When you open a DB, it acquire lock over the data directory. Hence, you cannot open the multiple instances of same underlying DB. There is an option BypassLockGuard badger/options.go at baadc01dca6e349820ed63fb444ea14fd87cb8b5 · dgraph-io/badger · GitHub that allows skipping taking that lock.
This option is not recommended and should only be used when opening all the instances in ReadOnly mode.
@Naman Thanks for your answer. So if I need to use the same db instance with multiple go routines, I should implement some kind of reference counting on it. Is there any pitfall if I just don’t close a db instance and use it in a long running daemon?
Closing the DB after usage is recommended. Badger can survive process crashes but not power failure. I would have to check how the daemons are stopped, I hope that stopping a daemon abruptly should be equivalent to stopping a process.
Does this mean Badger may lose data if the DB is not closed when power failure happens? I read the code a bit and find that the changes to memtables are saved to WAL first. Does this help with power failure?