[
https://issues.apache.org/jira/browse/ACCUMULO-3509?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15081706#comment-15081706
]
ASF GitHub Bot commented on ACCUMULO-3509:
------------------------------------------
Github user joshelser commented on a diff in the pull request:
https://github.com/apache/accumulo/pull/62#discussion_r48775109
--- Diff:
server/tserver/src/main/java/org/apache/accumulo/tserver/Tablet.java ---
@@ -1761,33 +1763,41 @@ Scanner createScanner(Range range, int num,
Set<Column> columns, Authorizations
private ScanDataSource isolatedDataSource;
private boolean sawException = false;
private boolean scanClosed = false;
+ private Semaphore scannerSemaphore;
--- End diff --
A javadoc comment describing why a semaphore is used would be nice when
looking at this code in the future.
> Scanner lock cause Tablet lock, hence preventing idle scans from being swept,
> hence blocking SimpleTimer thread
> ----------------------------------------------------------------------------------------------------------------
>
> Key: ACCUMULO-3509
> URL: https://issues.apache.org/jira/browse/ACCUMULO-3509
> Project: Accumulo
> Issue Type: Bug
> Components: tserver
> Affects Versions: 1.6.0
> Reporter: marco polo
> Assignee: marco polo
> Fix For: 1.6.5, 1.7.1, 1.8.0
>
>
> Synchronization with Tablet$Scanner via a read() will block close() being
> called via the sweep method in TabletServer. As a result, the SimpleTimer
> thread does not continue, and idle threads grow until the scan completes.
> My patch, which is forthcoming, converts synchronized methods to use a fair
> lock. If the lock is held by a read call, the close call will attempt to
> obtain it, time out, and return indicating a close was not successful. The
> sweep will continue, and the SimpleTimer thread will respawn later,
> attempting closure on those Tablets at a later time.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
