[SENTRY-1501] SentryStore shouldn't synchronize openTransaction() and commitUpdateTransaction()

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.7.0, 2.0.0
• Fix Version/s: 1.8.0, 2.0.0
• Component/s: Sentry
• Assignee: Alex Kolbasov
• Reporter: Alex Kolbasov
• Created: 12/Oct/16 22:15
• Updated: 24/Jul/17 14:51
• Resolved: 14/Nov/16 21:27

Description

SentryStore.openTransaction() is synchronized for no reason - the peristence manager factory is thread-safe.

The synchronization here doesn't make any sense at all:

  /**
   * Synchronized due to sequence id generation
   */
  public synchronized CommitContext commitUpdateTransaction(PersistenceManager pm) {
    commitTransaction(pm);
    return new CommitContext(SERVER_UUID, incrementGetSequenceId());
  }

  /**
   * Increments commitSequenceId which should not be modified outside
   * this method.
   *
   * @return sequence id
   */
  private synchronized long incrementGetSequenceId() {
    return ++commitSequenceId;
  }

Note that incrementGetSequenceId() is synchronized so there is no need to synchronize commitUpdateTransaction(). More over, there is no need to synchronize incrementGetSequenceId(), it can just use atomic for the index. And I think that handling of this atomic should be moved to the CommitContext instead.

Issue Links

• blocks: SENTRY-1491 Sentry transactions are not rolled back immediately when commit fails
• relates to: SENTRY-1422 JDO deadlocks while processing grant while a background thread processes Notificationlogs
• relates to: SENTRY-872 Uber jira for HMS HA + Sentry HA redesign