Adjusting cancel and ensure close

Author: Paultagoras

jdbc-v2/src/main/java/com/clickhouse/jdbc/ResultSetImpl.java

@@ -6,6 +6,7 @@
 import java.io.Reader;
 import java.math.BigDecimal;
 import java.net.MalformedURLException;
+import java.net.SocketException;
 import java.net.URL;
 import java.nio.charset.StandardCharsets;
 import java.sql.*;
@@ -68,23 +69,34 @@ public boolean next() throws SQLException {
     @Override
     public void close() throws SQLException {
         closed = true;
-        if (reader != null) {
-            try {
-                reader.close();
-            } catch (Exception e) {
-                throw ExceptionUtils.toSqlState(e);
-            }
 
-            reader = null;
+        Exception e = null;
+        try {
+            if (reader != null) {
+                try {
+                    reader.close();
+                } catch (Exception re) {
+                    log.debug("Error closing reader", re);
+                    e = re;
+                } finally {
+                    reader = null;
+                }
+            }
+        } finally {
+            if (response != null) {
+                try {
+                    response.close();
+                } catch (Exception re) {
+                    log.debug("Error closing response", re);
+                    e = re;
+                } finally {
+                    response = null;
+                }
+            }
         }
 
-        if (response != null) {
-            try {
-                response.close();
-            } catch (Exception e) {
-                throw ExceptionUtils.toSqlState(e);
-            }
-            response = null;
+        if (e != null) {
+            throw ExceptionUtils.toSqlState(e);
         }
     }
 

jdbc-v2/src/main/java/com/clickhouse/jdbc/StatementImpl.java

@@ -32,7 +32,7 @@ public class StatementImpl implements Statement, JdbcV2Wrapper {
     private OperationMetrics metrics;
     private List<String> batch;
     private String lastSql;
-    private String lastQueryId;
+    private volatile String lastQueryId;
     private String schema;
     private int maxRows;
 
@@ -207,8 +207,13 @@ public int executeUpdate(String sql, QuerySettings settings) throws SQLException
     public void close() throws SQLException {
         closed = true;
         if (currentResultSet != null) {
-            currentResultSet.close();
-            currentResultSet = null;
+            try {
+                currentResultSet.close();
+            } catch (Exception e) {
+                LOG.debug("Failed to close current result set", e);
+            } finally {
+                currentResultSet = null;
+            }
         }
     }
 
@@ -262,10 +267,10 @@ public void cancel() throws SQLException {
             return;
         }
 
-        try {
-            connection.client.query(String.format("KILL QUERY%sWHERE query_id = '%s'",
-                    connection.onCluster ? " ON CLUSTER " + connection.cluster + " " : " ",
-                    lastQueryId), connection.getDefaultQuerySettings()).get();
+        try (QueryResponse response = connection.client.query(String.format("KILL QUERY%sWHERE query_id = '%s'",
+                connection.onCluster ? " ON CLUSTER " + connection.cluster + " " : " ",
+                lastQueryId), connection.getDefaultQuerySettings()).get()){
+            LOG.debug("Query {} was killed by {}", lastQueryId, response.getQueryId());
         } catch (Exception e) {
             throw new SQLException(e);
         }

jdbc-v2/src/main/java/com/clickhouse/jdbc/internal/ExceptionUtils.java

@@ -61,4 +61,12 @@ public static SQLException toSqlState(String message, Exception cause) {
 
         return new SQLException(exceptionMessage, SQL_STATE_CLIENT_ERROR, cause);//Default
     }
+
+    public static Throwable getRootCause(Throwable throwable) {
+        Throwable cause = throwable;
+        while (cause.getCause() != null) {
+            cause = cause.getCause();
+        }
+        return cause;
+    }
 }