There is no ability to turn off the phantom validation. The idea behind range queries in update transactions is that you would scope them to a set of keys that you expect won't be updated concurrently. A classic example is updating all the assets you own with some information. You would do a range query over your assets to get them all, and then update them all in the same transaction. Since nobody else is authorized to update your assets, there typically would be no conflicts and the transaction would be validated and committed. However imagine if somebody transferred an asset to you while the transaction was in flight. You would miss the update on this transaction. The phantom check is designed to catch these types of conflicts.

If your application can tolerate phantoms, then you can design your application accordingly. For example you would first query for the set of assets, then submit a separate transaction to update the desired keys. Since the update transaction has no range query, there will be no conflicts detected. You still may 'miss' an update on an incoming asset, but that is either ok based on your application, or your application could detect that with a follow-on query and follow-on update in a subsequent transaction.

This all being said, I do see value in having the application specify as part of the transaction whether phantoms should be checked or not. I'd encourage you to open a Jira https://jira.hyperledger.org/issues/?filter=13110 and let's see if there is similar demand from others.


Dave Enyeart

"Tomás Peixinho" ---02/08/2021 12:20:46 PM---Good afternoon, I'm developing an application using Hyperledger Fabric that requires me to, in order

From: "Tomás Peixinho" <tom.peixinho@...>
To: "fabric@..." <fabric@...>
Date: 02/08/2021 12:20 PM
Subject: [EXTERNAL] [Hyperledger Fabric] Commit Phase Re-Validation - Phantom Reads
Sent by: fabric@...

Thanks - Andy Hurt has replied to the comment on stack overflow.

Matthew White

On Sat, Feb 6, 2021 at 06:06 AM, Tsvetan Georgiev wrote:

honestly

Hi Tsvetan, Thanks for such a detailed explanation, however, I don't fully comprehend your last point. Can you elaborate further on that? If it is not a single network, then how does it make sense to onboard different participants if they need to share data across each other? Also, how does the concept of trust get established if the network itself is isolated by particiapnts?

Thanks, Samyak Jain

type Permission struct {
    PermissionId    string `json:"permissionId"` // doctorId + dataCategory + patientId
    DataCategory    string `json:"dataCategory"`
    PatientId       string `json:"patientId"`
    DoctorId        string `json:"doctorId"`
    Right           string `json:"right"` // read/write
    From            string `json:"from"`
    To              string `json:"to"`
}

peer chaincode query -C mychannel -n permissions -c '{"Args":["ListDoctorPermissions", "doctor1"]}'

Error: endorsement failure during query. response: status:500 message:"Error handling success response. Value did not match schema:\n1. return: Invalid type. Expected: array, given: string" 

func (s *SmartContract) ListDoctorPermissions(ctx contractapi.TransactionContextInterface, doctorId string) ([]byte, error) {
    doctorIterator, err := ctx.GetStub().GetStateByPartialCompositeKey("permissionId", []string{doctorId})
    if err != nil {
        return nil, err
    }
    fmt.Printf("the doctor Iterator is: %s", doctorIterator)

    defer doctorIterator.Close()

    var dataCategory string
    var patientId string
    var permissionId string

    var permissions []byte
    bArrayPermissionAlreadyWritten := false

    for doctorIterator.HasNext() {
        responseRange, err := doctorIterator.Next()
        if err != nil {
            return nil, err
        }

        objectType, compositeKeyParts, err := ctx.GetStub().SplitCompositeKey(responseRange.Key)
        if err != nil {
            return nil, err
        }
        fmt.Printf("the objectType is: %s", objectType)

        dataCategory = compositeKeyParts[1]
        patientId = compositeKeyParts[2]
        permissionId = doctorId + dataCategory + patientId
        fmt.Printf("the compositeKeyParts are: %s", compositeKeyParts[0], compositeKeyParts[1], compositeKeyParts[2])

        permissionAsBytes, err := ctx.GetStub().GetState(permissionId)
        if err != nil {
            return nil, err
        }

        if bArrayPermissionAlreadyWritten == true {
            newBytes := append([]byte(","), permissionAsBytes...)
            permissions = append(permissions, newBytes...)
        } else {
            permissions = append(permissions, permissionAsBytes...)
            fmt.Print(permissions)
        }

        fmt.Printf("Found a asset for index : %s asset id : ", objectType, compositeKeyParts[0], compositeKeyParts[1], compositeKeyParts[2])
        bArrayPermissionAlreadyWritten = true

    }

    permissions = append(permissions, []byte("]")...)
    fmt.Print(permissions)
    return permissions, nil
}

Hyperledger Fabric Documentation Workgroup call - Western hemisphere

When:
Friday, 5 February 2021
11:00am to 12:00pm
(GMT-05:00) America/New York

Where:
https://zoom.us/my/hyperledger.community.backup?pwd=dkJKdHRlc3dNZEdKR1JYdW40R2pDUT09

Organizer:
pama@...

Description:
Documentation workgroup call.
Agenda, minutes and recordings :https://wiki.hyperledger.org/display/fabric/Documentation+Working+Group

Hi Community,

Want to ask how the peer and orderer hostnames in Hyperledger Fabric should be mapped across a cluster of nodes on the network? If some organization wants to join a running network, does it mean the hostnames used have to be accessible on the internet in order for the new organization to communicate with the existing network? By default, I presume they are private to the network like orderer0.org1.example.com, so if this needs to be accessed by other org peers not in the same subnet/VPC how does this work?

Thanks, Samyak Jain

Reminder: Hyperledger Fabric Documentation Workgroup call - Western hemisphere

When: Friday, 5 February 2021, 11:00am to 12:00pm, (GMT-05:00) America/New York

Where:https://zoom.us/my/hyperledger.community.backup?pwd=dkJKdHRlc3dNZEdKR1JYdW40R2pDUT09

View Event

Organizer: Pam Andrejko pama@...

Description: Documentation workgroup call.
Agenda, minutes and recordings :https://wiki.hyperledger.org/display/fabric/Documentation+Working+Group

Hi Community,

We are trying to explore using Kubernetes for deploying our Fabric network. We want to understand what level of automation will be possible using Kubernetes? Are things like deploying chaincodes, adding a new peer organization, joining existing peer to a new channel, onboarding a new orderer, etc. able to be automated on Kubernetes?

Also are there any limitations we should keep in mind for this kind of architecture?

Thanks, Samyak Jain

Hyperledger Fabric v2.3.1 is now available.

If you are using the new osnadmin command to create ordering service channels, note that the flag --channel-id has been corrected to be --channelID.

More details in the release notes:
https://github.com/hyperledger/fabric/releases/tag/v2.3.1