[FLINK-31063] Prevent duplicate reading when restoring from a checkpoint.

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: mongodb-1.0.0
• Fix Version/s: mongodb-1.0.0
• Component/s: Connectors / MongoDB
• Labels: pull-request-available
• Assignee: jiabao.sun
• Reporter: jiabao.sun
• Created: 14/Feb/23 10:48
• Updated: 20/Feb/23 10:22
• Resolved: 20/Feb/23 10:22

Description

Exact-once semantics may not be guaranteed at present on partial reads.
We use a number fetchSize to limit the records count for every fetch loop but we didn't record the offset into the split state. When resuming the split reader from a partially completed split, we may re-read some data.

We should record the current reading offset into split state.
Skip this offset when restoring to prevent duplicate reading.

Issue Links

• links to: GitHub Pull Request #3
• links to: GitHub Pull Request #3