add write batch

[pfi79]

hyperledger/fabric#5086

[pfi79]

@denyeart @C0rWin @satota2 @yacovm

[C0rWin]

While reading the PR, I thought we might miss an API that can abort or cancel the collecting batch. For instance, there might be logic where the user reads something from the state and decides not to send anything or perform a different batch of operations.

Wdyt @pfi79? @denyeart, if you think it might make sense, do we need to update the RFC to reflect it, or can we implement a suggested API, say, CancelWriteBatch()?

[pfi79]

While reading the PR, I thought we might miss an API that can abort or cancel the collecting batch. For instance, there might be logic where the user reads something from the state and decides not to send anything or perform a different batch of operations.

Wdyt @pfi79? @denyeart, if you think it might make sense, do we need to update the RFC to reflect it, or can we implement a suggested API, say, CancelWriteBatch()?

Let's talk about it. I wrote this change so that I don't have to change the chaincode for different peers. That is, those that support WriteBatch and those that do not (flag usePeerWriteBatch true or false). And I think that behaviour should not change, maximum in processing speed.

What will happen to your proposal if the old peer is next to the new chaincode?

In my variant, the call to StartWriteBatch will not fail, but it will be ignored and the sending of changes will follow the old one. What should CancelWriteBatch() do in this case?