Github user phrocker commented on a diff in the pull request:
https://github.com/apache/accumulo/pull/60#discussion_r48753512
--- Diff:
server/tserver/src/main/java/org/apache/accumulo/tserver/tablet/Scanner.java ---
@@ -38,100 +40,126 @@
private ScanDataSource isolatedDataSource;
private boolean sawException = false;
private boolean scanClosed = false;
+ protected Semaphore scannerSemaphore;
Scanner(Tablet tablet, Range range, ScanOptions options) {
this.tablet = tablet;
this.range = range;
this.options = options;
+ scannerSemaphore = new Semaphore(1, true);
}
- public synchronized ScanBatch read() throws IOException,
TabletClosedException {
-
- if (sawException)
- throw new IllegalStateException("Tried to use scanner after
exception occurred.");
+ public ScanBatch read() throws IOException, TabletClosedException {
if (scanClosed)
--- End diff --
I made a typo when writing the patch from my other machine. I made the
boolean volatile there but in talking with you I will move the scanClosed below
the acquisition to avoid the issue entirely and ensure cache coherency.
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