[OAK-8640] Allow to only copy last journal entry in the SegmentStoreMigrator

• Type: Story
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.18.0
• Component/s: segment-azure
• Assignee: Tomek Rękawek
• Reporter: Tomek Rękawek
• Created: 23/Sep/19 07:59
• Updated: 30/Sep/19 07:35
• Resolved: 24/Sep/19 14:07

Description

In the oak-segment-azure, reading the whole journal may be a time consuming task, as the blob appends are a bit slow to read. The OAK-8604 introduces an improvement, by keeping the most recent journal entry saved as a metadata in the journal.log blob. We should allow to use this optimization in SegmentStoreMigrator, by adding a new migration parameter - onlyLastJournalEntry. This way, only the last entry in the journal will be migrated and it won't require to read the whole journal.