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https://issues.apache.org/jira/browse/HTTPCLIENT-881?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12766636#action_12766636
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Tim Boemker commented on HTTPCLIENT-881:
----------------------------------------
I see that the code in AbstractClientConnAdapter.abortConnection was changed
from this:
// Usually #abortConnection() is expected to be called from
// a helper thread in order to unblock the main execution thread
// blocked in an I/O operation. It may be unsafe to call
// #releaseConnection() from the helper thread, so we have to rely
// on an IOException thrown by the closed socket on the main thread
// to trigger the release of the connection back to the
// connection manager.
//
// However, if this method is called from the main execution thread
// it should be safe to release the connection immediately. Besides,
// this also helps ensure the connection gets released back to the
// manager if #abortConnection() is called from the main execution
// thread while there is no blocking I/O operation.
if (executionThread.equals(Thread.currentThread())) {
releaseConnection();
}
to this:
if (connManager != null) {
connManager.releaseConnection(this, duration,
TimeUnit.MILLISECONDS);
}
Perhaps the comment in the original code was correct.
> AbstractClientConnAdapter doesn't ensure that only one of
> ConnectionReleaseTrigger.abortConnection, .releaseConnection has effect
> ---------------------------------------------------------------------------------------------------------------------------------
>
> Key: HTTPCLIENT-881
> URL: https://issues.apache.org/jira/browse/HTTPCLIENT-881
> Project: HttpComponents HttpClient
> Issue Type: Bug
> Components: HttpConn
> Affects Versions: 4.0 Final
> Reporter: Tim Boemker
> Fix For: 4.1 Alpha1
>
> Attachments: HTTPCLIENT-881.patch
>
>
> If HttpUriRequest.abort() is called at about the same time that the request
> completes, it's possible for an aborted connection to be returned to the
> pool. The next time the connection is used, HttpClient.execute fails without
> retrying, throwing this exception:
> java.io.IOException: Connection already shutdown
> at
> org.apache.http.impl.conn.DefaultClientConnection.opening(DefaultClientConnection.java:112)
> at
> org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:120)
> at
> org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:147)
> at
> org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:101)
> at
> org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:381)
> at
> org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:641)
> at
> org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:576)
> Steps to reproduce:
> 1) Set a breakpoint in ThreadSafeClientConnManager.releaseConnection just
> after "reusable" is set (and found to be true).
> 2) Run to the breakpoint in releaseConnection.
> 3) Call HttpUriRequest.abort.
> 4) Let releaseConnection complete.
> When the connection is next used, the exception will be thrown.
> Snippet from ThreadSafeClientConnManager:
> public void releaseConnection(ManagedClientConnection conn, long
> validDuration, TimeUnit timeUnit) {
> ...
> boolean reusable = hca.isMarkedReusable();
> if (log.isDebugEnabled()) { //
> breakpoint here
> if (reusable) {
> log.debug("Released connection is reusable.");
> } else {
> log.debug("Released connection is not reusable.");
> }
> }
> hca.detach();
> if (entry != null) {
> connectionPool.freeEntry(entry, reusable, validDuration,
> timeUnit);
> }
> }
> }
> I think that AbstractClientConnAdapter should be modified as follows:
> 1) Add "released" flag:
> /** True if the connection has been released. */
> private boolean released;
> 2) Modify abortConnection:
> public void abortConnection() {
> synchronized(this) {
> if (aborted || released) {
> return;
> }
> aborted = true;
> }
> unmarkReusable(); // this line and all that follow unchanged
> 3) Modify releaseConnection:
> public void releaseConnection() {
> synchronized(this) {
> if (aborted || released) {
> return;
> }
> released = true;
> }
> if (connManager != null) {
> connManager.releaseConnection(this, duration,
> TimeUnit.MILLISECONDS);
> }
> }
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