Block Header Metadata Modification, Changing the Transaction Flow

Hello,

Apologies if this issue seems out of place, but I am seeking guidance from anyone actively involved in maintaining the Hyperledger Fabric project or well-versed in its codebase. I have previously addressed several questions on Discord and received responses to few of them.

I am using the Hyperledger Fabric v2.2 branch.

I am currently looking to implement an additional structure within each block's header. This would facilitate efficient querying of the transaction history by checking each block's header before executing the `getHistoryForKey()` function. This process would verify if the key being searched for exists within the specified block, potentially minimizing the time required for queries.

Thus far, I have modified `common.pb.go` to include a new field added to the Block's Header. Following that, I have updated `orderer/common/multichannel/blockwriter.go` to incorporate the logic necessary to create a bloom-filter like structure with each new block, through modifications to the `func (bw *BlockWriter) CreateNextBlock(messages []*cb.Envelope) *cb.Block {}` function.

However, I'm at an impasse when it comes to modifying how queries are processed. My initial plan was to design a new method based on `.getHistoryForKey` and incorporate a check within this method. Unfortunately, I have been unable to locate where `.getHistoryForKey()` is defined.

Could you provide guidance on the most efficient approach to implementing what I have outlined above? Your expertise and input would be greatly appreciated.

Thank you,