[FLINK-17766] Use checkpoint lock instead of fine-grained locking in Kafka AbstractFetcher

• Type: Sub-task
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.11.0
• Component/s: Connectors / Kafka
• Assignee: Aljoscha Krettek
• Reporter: Aljoscha Krettek
• Created: 16/May/20 19:06
• Updated: 18/May/20 04:58
• Resolved: 18/May/20 04:58

Description

In emitRecordsWithTimestamps(), we are currently locking on the partition state object itself to prevent concurrent access (and to make sure that changes are visible across threads). However, after recent changes (FLINK-17307) we hold the checkpoint lock for emitting the whole "bundle" of records from Kafka. We can now also just use the checkpoint lock in the periodic emitter callback and then don't need the fine-grained locking on the state for record emission.