[ROCKETMQ-261] IndexService may block ReputMessageService

• Type: Bug
• Status: Reopened
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 4.0.0-incubating, 4.1.0-incubating
• Fix Version/s: 4.3.0
• Component/s: rocketmq-store
• Assignee: Xinyu Zhou
• Reporter: Xinyu Zhou
• Created: 10/Aug/17 13:24
• Updated: 13/Dec/17 12:31

Description

So far, ReputMessageService will do two things serially:

1. Dispatch message to consume queue.
2. Build message index

IndexService uses read/write lock to ensure thread safe, build index will acquire read lock, while clean index files will hold write lock for a long time. That means clean index files will block build index, hence will block dispatch consume queue and influence real-time of consumption.

private void deleteExpiredFile(List<IndexFile> files) {
        if (!files.isEmpty()) {
            try {
                this.readWriteLock.writeLock().lock();
                for (IndexFile file : files) {
                    boolean destroyed = file.destroy(3000);
                    destroyed = destroyed && this.indexFileList.remove(file);
                    if (!destroyed) {
                        log.error("deleteExpiredFile remove failed.");
                        break;
                    }
                }
            } catch (Exception e) {
                log.error("deleteExpiredFile has exception.", e);
            } finally {
                this.readWriteLock.writeLock().unlock();
            }
        }
    }

Action:

Submits task 1 and 2 to different thread, to avoid mutual influence.
Or uses lock-free algorithm in IndexService.