| << Back to previous view |
|
[QB-1562] Possible deadlock in DbStore.close()
|
|
| Status: | Resolved |
| Project: | QuickBuild |
| Component/s: | None |
| Affects Version/s: | 5.0.7 |
| Fix Version/s: | 5.0.9 |
| Type: | Bug | Priority: | Major |
| Reporter: | Marek Baczynski | Assigned To: | Unassigned |
| Resolution: | Fixed | Votes: | 0 |
| Remaining Estimate: | Unknown | Time Spent: | Unknown |
| Original Estimate: | Unknown | ||
| Environment: | all | ||
| Description |
|
connection.close() can throw an SQLException - if this happens, lock will not unlock:
public void close() { if (logger.isDebugEnabled()) { logger.debug("Closing database " + this + " and releasing lock"); } try { if (connection != null) { connection.close(); // THROW HERE connection = null; } if (lock != null) { lock.unlock(); // ...unlock skipped lock = null; } ConnectionCache.INSTANCE.remove(dbDir.getAbsolutePath(), mode, method); } catch (SQLException e) { throw Throwables.propagate(e); } } |
| Comments |
| Comment by Marek Baczynski [ 27/Feb/13 08:47 AM ] |
|
related issue is in DbStore.open(), near getConnection():
public void open(Mode mode, String method) { if (logger.isDebugEnabled()) { logger.debug("Trying opening the database " + this + " ..."); } Preconditions.checkState(connection == null); Preconditions.checkState(lock == null); this.method = method; if (!exists()) { if (logger.isDebugEnabled()) { logger.debug("Database doesn't exist, creating database " + this + " and opening with READ_WRITE mode"); } this.mode = Mode.READ_WRITE; this.lock = getLock(); this.connection = getConnection(getUrl(false)); // THROW HERE - lock does not unlock() createDb(); ... |
| Comment by Steve Luo [ 27/Feb/13 02:15 PM ] |
|
Thank you very much for pointing this out.
The usage for DbStore should like below: try { db.open(); // do some db related query/update work } finally { db.close(); } So, if there is any exception occurred in open(), the close() will finally close the connection and release the lock. But it may be more safe to call close() when exception occurred during open() call. |