public_state.data will be different depending on whether you use leveldb or couchdb, since couchdb saves the JSON in a different format.
private_state_hashes.data should always be the same since the hashes are stored consistently as binary regardless of the state database choice.
If you are seeing differences in private_state_hashes.data, then your private state database may not be correct on one of your peers. You can check snapshot on a 3rd peer to determine which of your original peers may not be correct. This is one of the purposes of the new snapshot capability - to determine if one of the state databases has gotten corrupted.
Dave Enyeart
"Yoojin Chang" ---02/24/2021 02:07:44 AM---I created snapshots from 2 peers for same channel and same height. When I checked _snapshot_signable
From: "Yoojin Chang" <arashi213@...>
To: fabric@...
Date: 02/24/2021 02:07 AM
Subject: [EXTERNAL] [Hyperledger Fabric] Differences in private_state_hashes.data of snapshots when using different StateDB
Sent by: fabric@...
I created snapshots from 2 peers for same channel and same height. When I checked _snapshot_signable_metadata.json file, "private_state_hashes.data" and "public_state.data" were different in each snapshot. I thought it is because peers use I created snapshots from 2 peers for same channel and same height.
When I checked _snapshot_signable_metadata.json file, "private_state_hashes.data" and "public_state.data" were different in each snapshot.
I thought it is because peers use different StateDB and couchdb sorts keys of data in alphabetical order.
peer id | statedb | key order in statedb (chaincode - fabcar) |
| peer0.org1.example.com | leveldb | make, model, colour, owner |
| peer0.org2.example.com | couchdb | colour, make, model, owner |
So I created another channel and deployed chaincode which has data keys sorted by alphabetical order.
(As a result, channels have same peers, chaincode definition and chaincode data except for channel name and chaincode name.)
In this case, snapshots from peers have same "private_state_hashes.data" and "public_state.data”.
But I can’t understand that private_state_hashes in snapshots are sometimes equal and sometimes different.
As I know, all peers in a channel always share same private data hashes.
If it would be different depends on StateDB type, I should always have gotten different results, but I didn’t.
When do differences of private data hashes in snapshots occur?
