[KAFKA-8521] Client unable to get a complete transaction set of messages using a single poll call

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: clients
• Assignee: Unassigned
• Reporter: Boris Rybalkin
• Created: 10/Jun/19 20:53
• Updated: 10/Jun/19 20:53

Description

I am unable to reliably get a complete list of messages from a successful transaction on a client side.

What I get instead sometimes is a subset of a complete transaction in one poll and a second half of a transaction in a second poll.

Am I right that poll should always give me a full transaction message set if a transaction was committed and client uses read_committed isolation level or not?

 

Pseudo code:

Server:

begin transaction

send (1, "test1")

send (2, "test2")

commit transaction

 

Client:

isolation level: read_committed

poll -> [ 1 ]

poll -> [ 2 ]

 

What I want is:

poll -> [1, 2]

 

Also what I observed, when keys are the same for the messages in the transaction I always get a complete message set in one poll, but when keys are very different in inside transaction I usually get transaction spread across multiple polls.

 

I can provide a working example if you think that this is a bug and not a misunderstanding of how poll works.