Improved driver performance when closing statements with partially re…

…ad results
aws · Dec 13, 2023 · befa7de · befa7de
1 parent 3c5fcf8
commit befa7de
Show file tree

Hide file tree

Showing 2 changed files with 4 additions and 38 deletions.
diff --git a/src/main/java/com/amazon/redshift/jdbc/RedshiftConnectionImpl.java b/src/main/java/com/amazon/redshift/jdbc/RedshiftConnectionImpl.java
@@ -259,6 +259,10 @@ public RedshiftConnectionImpl(HostSpec[] hostSpecs,
     {
         String iamCredentialProvider = RedshiftConnectionImpl.getOptionalConnSetting(
             RedshiftProperty.CREDENTIALS_PROVIDER.getName(), info);
+        if(iamCredentialProvider != null && iamCredentialProvider.equalsIgnoreCase(RedshiftConstants.IDP_TOKEN_PLUGIN)) {
+          throw new RedshiftException(GT.tr("You can not use this authentication plugin with IAM enabled."),
+                RedshiftState.UNEXPECTED_ERROR);
+        }
 
     	if (sslExplicitlyDisabled) {
 	      	throw new RedshiftException(GT.tr("SSL should be enable in IAM authentication."),

diff --git a/src/main/java/com/amazon/redshift/jdbc/RedshiftStatementImpl.java b/src/main/java/com/amazon/redshift/jdbc/RedshiftStatementImpl.java
@@ -746,14 +746,6 @@ public final void close() throws SQLException
       isClosed = true;
     }
 
-    // The user has closed the statement and does not want to read any more results. We send a cancellation request to
-    // the server. It is possible to have a situation where if the driver's ring buffer is not
-    // reading from the stream and the server's send buffer is full. The server treats this as a client side hang and
-    // closes the connection. To avoid this, we start reading from the stream again, but we throw away the rows we read
-    // because the user no longer needs them. Note, this is a temporary fix until a permanent server-side fix can be
-    // provided.
-    resumeReadAndDiscardResults();
-
     cancel();
 
     closeForNextExecution();
@@ -1578,34 +1570,4 @@ public ResultSet createDriverResultSet(Field[] fields, List<Tuple> tuples)
 
   protected void transformQueriesAndParameters() throws SQLException {
   }
-
-  private void resumeReadAndDiscardResults()
-  {
-    if (connection.getQueryExecutor().isRingBufferThreadRunning())
-    {
-      RedshiftResultSet rs = null;
-      if (firstUnclosedResult != null)
-      {
-        rs = (RedshiftResultSet) firstUnclosedResult.getResultSet();
-      }
-      if (rs != null && rs.queueRows != null)
-      {
-        boolean endOfResult = rs.queueRows.endOfResult();
-        if(!endOfResult)
-        {
-          rs.queueRows.setSkipRows();
-
-          // We sleep here for 2 seconds to give the ring buffer adequate time to start reading results again once it wakes up,
-          // and the server adequate time to detect that send buffer is no longer full
-          try
-          {
-            Thread.sleep(2000);
-          }
-          catch (InterruptedException e)
-          {
-          }
-        }
-      }
-    }
-  }
 }