[OAK-6653] Standby server must always send the persisted head to clients

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.7.7
• Fix Version/s: 1.7.8, 1.8.0
• Component/s: segment-tar, tarmk-standby
• Labels: cold-standby
• Assignee: Andrei Dulceanu
• Reporter: Andrei Dulceanu
• Created: 12/Sep/17 12:46
• Updated: 04/Oct/19 17:52
• Resolved: 15/Sep/17 11:37

Description

Currently the standby server sends an un-persisted head record to clients. Under normal circumstances, the TarMK flush thread is able to persist it and its corresponding segment at a 5 seconds interval.
However, there are cases (uploading a very large blob > 10 GB) in which the flush thread writes the segment too late, and the 20s allowed by FileStoreUtil#readSegmentWithRetry are not enough. Therefore the server can't read the segment containing the head record and a timeout occurs on the client.