commit b958a96c1a31fce245f1c3b2c89702e6fb19a97a
author alexander.behm <alexander.behm@123451ca-8445-de46-9d55-352943316053> Sun Jun 24 03:50:26 2012 +0000
committer alexander.behm <alexander.behm@123451ca-8445-de46-9d55-352943316053> Sun Jun 24 03:50:26 2012 +0000
tree 2348ba1cea86d7cd100b847c46e89a9b0c27548b
parent 68dc82ea73933513a199100bc5b87a6af52a41a6

Fixed a race in BufferCache.pin() that very rarely caused deadlock in the lsm multithreading tests.

git-svn-id: https://hyracks.googlecode.com/svn/branches/hyracks_lsm_tree@1588 123451ca-8445-de46-9d55-352943316053

hyracks-storage-common/src/main/java/edu/uci/ics/hyracks/storage/common/buffercache/BufferCache.java

diff --git a/hyracks-storage-common/src/main/java/edu/uci/ics/hyracks/storage/common/buffercache/BufferCache.java b/hyracks-storage-common/src/main/java/edu/uci/ics/hyracks/storage/common/buffercache/BufferCache.java
index 7abb20c..aa53a39 100644
--- a/hyracks-storage-common/src/main/java/edu/uci/ics/hyracks/storage/common/buffercache/BufferCache.java
+++ b/hyracks-storage-common/src/main/java/edu/uci/ics/hyracks/storage/common/buffercache/BufferCache.java
@@ -146,21 +146,11 @@
                     + BufferedFileHandle.getPageId(dpid) + " because all pages are pinned.");
         }
         if (!newPage) {
-            if (!cPage.valid) {
-                /*
-                 * We got a buffer and we have pinned it. But its invalid. If
-                 * its a new page, we just mark it as valid and return. Or else,
-                 * while we hold the page lock, we get a write latch on the data
-                 * and start a read.
-                 */
-                cPage.acquireWriteLatch(false);
-                try {
-                    if (!cPage.valid) {
-                        read(cPage);
-                    }
+            // Resolve race of multiple threads trying to read the page from disk.
+            synchronized (cPage) {
+                if (!cPage.valid) {
+                    read(cPage);
                     cPage.valid = true;
-                } finally {
-                    cPage.releaseWriteLatch();
                 }
             }
         } else {