[BOOKKEEPER-302] No more messages delivered when hub server scans messages over two ledgers.

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 4.1.0
• Fix Version/s: 4.2.0
• Assignee: Sijie Guo
• Reporter: Sijie Guo
• Created: 20/Jun/12 08:48
• Updated: 13/Feb/13 15:46
• Resolved: 28/Jun/12 17:22

Description

This issue introduce when fixing BOOKKEEPER-215.

suppose topic T has four messages, message 1 is in ledger 1 while message 2~4
are in ledger 2. Hub server issue scan (1, 2) and scan (3, 4).

If hub server works correctly, it just tried to read entry 0 in ledger 1 and
entry 0 in ledger 2 during scan (1,2), while reading entry 1, 2 in ledger 2
during scan (3,4).

But unfortunately, after fixing BOOKKEEPER-215, scan (1,2) would read 0 in
ledger 1 and read 0, 1 in ledger 2. so reading entry 1 of ledger 2 would be
issued concurrently in different scans and one reading would fail without any callback (this issue is BOOKKEEPER-49).

Then the systems would be blocked there wait for the response of reading 1 of
ledger 2 and no messages would be delivered.

To fix this issue, two thing would be done.

1) fix scan issue in hub server to avoid overlapping scanning.
2) fix read issue in bookkeeper client.

fixing 1) could resolve this issue, but it would be better to fix 2) also. it should be in jira BOOKKEEPER-49.

Issue Links

• relates to: BOOKKEEPER-49 bookkeeper - parallel async read same entry of same ledger will fail