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https://issues.apache.org/jira/browse/HBASE-7685?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13564101#comment-13564101
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Ted Yu edited comment on HBASE-7685 at 1/28/13 3:01 PM:
--------------------------------------------------------
Thanks for your concern. There is a deep discussion about PoolMap in 6651.
>From the discussion, I understand that there are risks when invoke put/get
method concurrently. From source code of HBaseClient, I found that there are
'synchronized' protection when modifying connections as follows:
// code for get or create a connection
{code}
synchronized (connections) {
connection = connections.get(remoteId);
if (connection == null) {
connection = createConnection(remoteId);
connections.put(remoteId, connection);
}
}
{code}
// code for close connection
{code}
synchronized (connections) {
connections.remove(remoteId, this);
}
{code}
was (Author: cuijianwei):
Thanks for your concern. There is a deep discussion about PoolMap in 6651.
From the discussion, I understand that there are risks when invoke put/get
method concurrently. From source code of HBaseClient, I found that there are
'synchronized' protection when modifying connections as follows:
// code for get or create a connection
{code}
synchronized (connections) {
connection = connections.get(remoteId);
if (connection == null) {
connection = createConnection(remoteId);
connections.put(remoteId, connection);
}
}
{code}
// code for close connection
synchronized (connections) {
connections.remove(remoteId, this);
}
> Closing socket connection can't be removed from SecureClient
> ------------------------------------------------------------
>
> Key: HBASE-7685
> URL: https://issues.apache.org/jira/browse/HBASE-7685
> Project: HBase
> Issue Type: Bug
> Components: security
> Affects Versions: 0.94.3
> Reporter: cuijianwei
> Attachments:
> closing_socket_connection_not_removed_in_secure_client.diff
>
>
> We found many IOExceptions naming "Call # not added as the connection # is
> closing" when using SecureClient to access hbase. From the source code of
> SecureClient, we found there may be bug in close() method of SecureClient.
> The following is the current logic in close() method of SecureClient：
> {code}
> // release the resources
> // first thing to do;take the connection out of the connection list
> synchronized (connections) {
> if (connections.get(remoteId) == this) {
> connections.remove(remoteId);
> }
> }
> {code}
> However, connections are managed by PoolMap； therefore, if more than one
> connection are created for the same remoteId, the 'if condition' may not be
> satisfied because the default PoolType is RoundRobin. This could be cause a
> closing state connection can't be removed from connections, making new calls
> which use such connections will always throws IOException naming "connection
> is closing".
> We can use logic from close() method of HBaseClient to resolve the problem:
> {code}
> // release the resources
> // first thing to do;take the connection out of the connection list
> synchronized (connections) {
> connections.remove(remoteId, this);
> }
> {code}
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