dlr 2003/06/20 01:12:50
Modified: src/java/org/apache/torque/manager Tag: TORQUE_3_0_BRANCH
AbstractBaseManager.java MethodResultCache.java
Log:
Backported delta between CVS revision 1.14 and 1.15 of
AbstractBaseManager.java and 1.16 and 1.17 of MethodResultCache.java
to the tip of the 3.0 branch (~3.0.2):
Corrected deadly multi-CPU thread deadlock problem discovered by Ed
Korthof <[EMAIL PROTECTED]> and John McNally <[EMAIL PROTECTED]>. The
problem was due to emulation of synchronization using an int counter
(to improve performance by avoiding Java "synchronized" keyword).
Post-increment and decrement operators compile to three op codes (with
Sun's JDK 1.3.1 for Linux), unsafe on a multi-CPU box.
* src/java/org/apache/torque/manager/AbstractBaseManager.java
lockCache, inGet, cacheGet(), removeInstanceImpl(),
putInstanceImpl(): Removed use of lockeCache and inGet instance
fields, replaced by consistent use of Java's "synchronized" keyword
(on the current instance, "this").
getMethodResultCache(), addCacheListenerImpl(), createSubsetList(),
readObject(): Added JavaDoc.
* src/java/org/apache/torque/manager/MethodResultCache.java
lockCache, getImpl(), putImpl(), get(): Removed use of lockeCache
instance fields, replaced by consistent use of Java's "synchronized"
keyword (on the current instance, "this").
remove(): Added error messages to several method overloads.
Reviewed by: John McNally
Issue: PCN19237
Revision Changes Path
No revision
No revision
1.11.2.1 +40 -52
db-torque/src/java/org/apache/torque/manager/AbstractBaseManager.java
Index: AbstractBaseManager.java
===================================================================
RCS file:
/home/cvs/db-torque/src/java/org/apache/torque/manager/AbstractBaseManager.java,v
retrieving revision 1.11
retrieving revision 1.11.2.1
diff -u -u -r1.11 -r1.11.2.1
--- AbstractBaseManager.java 29 Nov 2002 13:16:05 -0000 1.11
+++ AbstractBaseManager.java 20 Jun 2003 08:12:50 -0000 1.11.2.1
@@ -63,6 +63,7 @@
import java.util.Iterator;
import java.io.Serializable;
import java.io.IOException;
+import java.io.ObjectInputStream;
import org.apache.commons.collections.FastArrayList;
import org.apache.jcs.JCS;
@@ -102,8 +103,6 @@
private String region;
- private boolean lockCache;
- private int inGet;
private boolean isNew = true;
protected Map validFields;
@@ -215,18 +214,9 @@
Persistent om = null;
if (cache != null)
{
- if (lockCache)
- {
- synchronized (this)
- {
- om = (Persistent) cache.get(key);
- }
- }
- else
+ synchronized (this)
{
- inGet++;
om = (Persistent) cache.get(key);
- inGet--;
}
}
return om;
@@ -256,29 +246,19 @@
Persistent oldOm = null;
if (cache != null)
{
- synchronized (this)
+ try
{
- lockCache = true;
- try
+ synchronized (this)
{
oldOm = (Persistent) cache.get(key);
- while (inGet > 0)
- {
- Thread.yield();
- }
cache.remove(key);
}
- catch (CacheException ce)
- {
- lockCache = false;
- throw new TorqueException(
- "Could not remove from cache due to internal JCS error.",
- ce);
- }
- finally
- {
- lockCache = false;
- }
+ }
+ catch (CacheException ce)
+ {
+ throw new TorqueException
+ ("Could not remove from cache due to internal JCS error",
+ ce);
}
}
return oldOm;
@@ -306,28 +286,18 @@
Persistent oldOm = null;
if (cache != null)
{
- synchronized (this)
+ try
{
- lockCache = true;
- try
+ synchronized (this)
{
oldOm = (Persistent) cache.get(key);
- while (inGet > 0)
- {
- Thread.yield();
- }
cache.put(key, om);
}
- catch (CacheException ce)
- {
- lockCache = false;
- throw new TorqueException(
- "Could not cache due to internal JCS error.", ce);
- }
- finally
- {
- lockCache = false;
- }
+ }
+ catch (CacheException ce)
+ {
+ throw new TorqueException
+ ("Could not cache due to internal JCS error", ce);
}
}
return oldOm;
@@ -470,6 +440,9 @@
}
}
+ /**
+ * @return The cache instance.
+ */
public MethodResultCache getMethodResultCache()
{
if (isNew)
@@ -494,7 +467,10 @@
{
}
-
+ /**
+ *
+ * @param listener A new listener for cache events.
+ */
public void addCacheListenerImpl(CacheListener listener)
{
List keys = listener.getInterestedFields();
@@ -538,6 +514,11 @@
}
}
+ /**
+ *
+ * @param key
+ * @return A subset of the list identified by <code>key</code>.
+ */
private synchronized List createSubsetList(String key)
{
FastArrayList list = null;
@@ -597,7 +578,14 @@
out.defaultWriteObject();
}
- private void readObject(java.io.ObjectInputStream in)
+ /**
+ * Helper methods for the <code>Serializable</code> interface.
+ *
+ * @param in The stream to read a <code>Serializable</code> from.
+ * @throws IOException
+ * @throws ClassNotFoundException
+ */
+ private void readObject(ObjectInputStream in)
throws IOException, ClassNotFoundException
{
in.defaultReadObject();
@@ -611,8 +599,8 @@
}
catch (Exception e)
{
- category.error("Cache could not be initialized for region: "
- + region + "after deserialization");
+ category.error("Cache could not be initialized for region '"
+ + region + "' after deserialization");
}
}
}
1.13.2.1 +19 -57
db-torque/src/java/org/apache/torque/manager/MethodResultCache.java
Index: MethodResultCache.java
===================================================================
RCS file:
/home/cvs/db-torque/src/java/org/apache/torque/manager/MethodResultCache.java,v
retrieving revision 1.13
retrieving revision 1.13.2.1
diff -u -u -r1.13 -r1.13.2.1
--- MethodResultCache.java 29 Nov 2002 13:16:05 -0000 1.13
+++ MethodResultCache.java 20 Jun 2003 08:12:50 -0000 1.13.2.1
@@ -66,7 +66,8 @@
import org.apache.torque.TorqueException;
/**
- * This class provides a cache for convenient storage of method results
+ * This class provides a cache for convenient storage of method
+ * results.
*
* @author <a href="mailto:[EMAIL PROTECTED]">John McNally</a>
* @version $Id$
@@ -81,7 +82,6 @@
"org.apache.torque.manager.MethodCacheKey";
private ObjectPool pool;
private GroupCacheAccess jcsCache;
- private boolean lockCache;
private int inGet;
private Map groups;
@@ -124,18 +124,9 @@
Object result = null;
if (jcsCache != null)
{
- if (lockCache)
- {
- synchronized (this)
- {
- result = jcsCache.getFromGroup(key, key.getGroupKey());
- }
- }
- else
+ synchronized (this)
{
- inGet++;
result = jcsCache.getFromGroup(key, key.getGroupKey());
- inGet--;
}
}
@@ -160,28 +151,18 @@
Object old = null;
if (jcsCache != null)
{
- synchronized (this)
+ try
{
- lockCache = true;
- try
+ synchronized (this)
{
old = jcsCache.getFromGroup(key, group);
- while (inGet > 0)
- {
- Thread.yield();
- }
jcsCache.putInGroup(key, group, value);
}
- catch (CacheException ce)
- {
- lockCache = false;
- throw new TorqueException(
- "Could not cache due to internal JCS error.", ce);
- }
- finally
- {
- lockCache = false;
- }
+ }
+ catch (CacheException ce)
+ {
+ throw new TorqueException
+ ("Could not cache due to internal JCS error", ce);
}
}
return old;
@@ -195,27 +176,8 @@
{
synchronized (this)
{
- lockCache = true;
- try
- {
- old = jcsCache.getFromGroup(key, key.getGroupKey());
- while (inGet > 0)
- {
- Thread.yield();
- }
- jcsCache.remove(key, key.getGroupKey());
- }
- // jcs does not throw an exception here, might remove this
- catch (Exception ce)
- {
- lockCache = false;
- throw new TorqueException(
- "Could not cache due to internal JCS error.", ce);
- }
- finally
- {
- lockCache = false;
- }
+ old = jcsCache.getFromGroup(key, key.getGroupKey());
+ jcsCache.remove(key, key.getGroupKey());
}
}
return old;
@@ -520,7 +482,7 @@
}
catch (Exception e)
{
- log.error("", e);
+ log.error("Error removing element", e);
}
}
return result;
@@ -544,12 +506,12 @@
catch (Exception e)
{
log.warn(
- "Nonfatal error. Could not return key to pool", e);
+ "Nonfatal error: Could not return key to pool", e);
}
}
catch (Exception e)
{
- log.error("", e);
+ log.error("Error removing element from cache", e);
}
}
return result;
@@ -579,7 +541,7 @@
}
catch (Exception e)
{
- log.error("", e);
+ log.error("Error removing element from cache", e);
}
}
return result;
@@ -602,12 +564,12 @@
catch (Exception e)
{
log.warn(
- "Nonfatal error. Could not return key to pool", e);
+ "Nonfatal error: Could not return key to pool", e);
}
}
catch (Exception e)
{
- log.error("", e);
+ log.error("Error removing element from cache", e);
}
}
return result;
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