fixed max rows. added check for execute method if they supported with specific parameters.

Author: chernser

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

@@ -1,5 +1,7 @@
 package com.clickhouse.jdbc;
 
+import com.clickhouse.client.api.internal.ServerSettings;
+
 import java.util.Collections;
 import java.util.List;
 
@@ -35,6 +37,16 @@ public enum DriverProperties {
      *  Enables closing result set before
      */
     RESULTSET_AUTO_CLOSE("jdbc_resultset_auto_close", "true"),
+
+    /**
+     * Enables using server property `max_result_rows` ({@link ServerSettings#MAX_RESULT_ROWS} to limit number of rows returned by query.
+     * Enabling this property will override user set overflow mode. It may cause error if server doesn't allow changing properties.
+     * When this property is not enabled then result set will stop reading data once limit is reached. As server may have
+     * more in a result set then it will require time to read all data to make HTTP connection usable again. In most cases
+     * this is fine. It is recommended to set limit in SQL query.
+     *
+     */
+    USE_MAX_RESULT_ROWS("jdbc_use_max_result_rows", "false"),
     ;
 
 

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

@@ -57,6 +57,9 @@ public class ResultSetImpl implements ResultSet, JdbcV2Wrapper {
     private int rowPos;
 
     private int fetchSize;
+    private int fetchDirection;
+    final private int maxFieldSize;
+    final private int maxRows;
 
     private Consumer<Exception> onDataTransferException;
 
@@ -77,6 +80,9 @@ public ResultSetImpl(StatementImpl parentStatement, QueryResponse response, Clic
         this.defaultCalendar = parentStatement.getConnection().defaultCalendar;
         this.rowPos = BEFORE_FIRST;
         this.fetchSize = parentStatement.getFetchSize();
+        this.fetchDirection = parentStatement.getFetchDirection();
+        this.maxFieldSize = parentStatement.getMaxFieldSize();
+        this.maxRows = parentStatement.getMaxRows();
         this.onDataTransferException = onDataTransferException;
     }
 
@@ -103,6 +109,15 @@ private String columnIndexToName(int index) throws SQLException {
     public boolean next() throws SQLException {
         checkClosed();
 
+        if (rowPos == AFTER_LAST) {
+            return false;
+        }
+
+        if (maxRows > 0 && rowPos == maxRows) {
+            rowPos = AFTER_LAST;
+            return false;
+        }
+
         try {
             Object readerRow = reader.next();
             if (readerRow != null) {
@@ -543,7 +558,7 @@ public boolean isFirst() throws SQLException {
     @Override
     public boolean isLast() throws SQLException {
         checkClosed();
-        return !reader.hasNext() && rowPos != AFTER_LAST && rowPos != BEFORE_FIRST;
+        return (!reader.hasNext() || rowPos == maxRows) && rowPos != AFTER_LAST && rowPos != BEFORE_FIRST;
     }
 
     @Override
@@ -607,15 +622,16 @@ public boolean previous() throws SQLException {
     @Override
     public int getFetchDirection() throws SQLException {
         checkClosed();
-        return FETCH_FORWARD;
+        return fetchDirection;
     }
 
     @Override
     public void setFetchDirection(int direction) throws SQLException {
         checkClosed();
-        if (direction != ResultSet.FETCH_FORWARD) {
+        if (getType() == TYPE_FORWARD_ONLY && direction != ResultSet.FETCH_FORWARD) {
             throw new SQLException("This result set object is of FORWARD ONLY type. Only ResultSet.FETCH_FORWARD is allowed as fetchDirection.");
         }
+        fetchDirection = direction;
     }
 
     @Override

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

@@ -7,6 +7,7 @@
 import com.clickhouse.client.api.query.QuerySettings;
 import com.clickhouse.client.api.sql.SQLUtils;
 import com.clickhouse.jdbc.internal.ExceptionUtils;
+import com.clickhouse.jdbc.internal.FeatureManager;
 import com.clickhouse.jdbc.internal.ParsedStatement;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -29,6 +30,7 @@ public class StatementImpl implements Statement, JdbcV2Wrapper {
     ConnectionImpl connection;
     protected int queryTimeout;
     protected boolean isPoolable = false; // Statement is not poolable by default
+    private final FeatureManager featureManager;
 
     // State
     private volatile boolean closed;
@@ -60,6 +62,7 @@ public StatementImpl(ConnectionImpl connection) throws SQLException {
         this.resultSets=  new ConcurrentLinkedQueue<>();
         this.resultSetAutoClose = connection.getJdbcConfig().isSet(DriverProperties.RESULTSET_AUTO_CLOSE);
         this.escapeProcessingEnabled = true;
+        this.featureManager = new FeatureManager(connection.getJdbcConfig());
     }
 
     protected void ensureOpen() throws SQLException {
@@ -458,22 +461,22 @@ public boolean getMoreResults(int current) throws SQLException {
         return false; // false indicates that no more results (or it is an update count)
     }
 
-//    @Override
+//    @Override -- because doesn't exist in Java 8
     public String enquoteLiteral(String val) throws SQLException {
         return SQLUtils.enquoteLiteral(val);
     }
 
-//    @Override
+//    @Override -- because doesn't exist in Java 8
     public String enquoteIdentifier(String identifier, boolean alwaysQuote) throws SQLException {
         return SQLUtils.enquoteIdentifier(identifier, alwaysQuote);
     }
 
-//    @Override
+//    @Override -- because doesn't exist in Java 8
     public boolean isSimpleIdentifier(String identifier) throws SQLException {
         return SQLUtils.isSimpleIdentifier(identifier);
     }
 
-//    @Override
+//    @Override -- because doesn't exist in Java 8
     public String enquoteNCharLiteral(String val) throws SQLException {
         if (val == null) {
             throw new NullPointerException();
@@ -489,31 +492,37 @@ public ResultSet getGeneratedKeys() throws SQLException {
 
     @Override
     public int executeUpdate(String sql, int autoGeneratedKeys) throws SQLException {
+        featureManager.unsupportedFeatureThrow("executeUpdate(String, int)", autoGeneratedKeys != Statement.NO_GENERATED_KEYS);
         return executeUpdate(sql);
     }
 
     @Override
     public int executeUpdate(String sql, int[] columnIndexes) throws SQLException {
+        featureManager.unsupportedFeatureThrow("executeUpdate(String, int[])");
         return executeUpdate(sql);
     }
 
     @Override
     public int executeUpdate(String sql, String[] columnNames) throws SQLException {
+        featureManager.unsupportedFeatureThrow("executeUpdate(String, String[])");
         return executeUpdate(sql);
     }
 
     @Override
     public boolean execute(String sql, int autoGeneratedKeys) throws SQLException {
+        featureManager.unsupportedFeatureThrow("execute(String, int)", autoGeneratedKeys != Statement.NO_GENERATED_KEYS);
         return execute(sql);
     }
 
     @Override
     public boolean execute(String sql, int[] columnIndexes) throws SQLException {
+        featureManager.unsupportedFeatureThrow("execute(String, int[])");
         return execute(sql);
     }
 
     @Override
     public boolean execute(String sql, String[] columnNames) throws SQLException {
+        featureManager.unsupportedFeatureThrow("execute(String, String[])");
         return execute(sql);
     }
 
@@ -573,20 +582,23 @@ public long getLargeUpdateCount() throws SQLException {
     public void setLargeMaxRows(long max) throws SQLException {
         ensureOpen();
         maxRows = max;
-        // This method override user set overflow mode on purpose:
-        // 1. Spec clearly states that after calling this method with a limit > 0 all rows over limit are dropped.
-        // 2. Calling this method should not cause throwing exception for future queries what only `break` can guarantee
-        // 3. If user wants different behavior then they are can use connection properties.
-        if (max > 0) {
-            localSettings.setOption(ClientConfigProperties.serverSetting(ServerSettings.MAX_RESULT_ROWS), maxRows);
-            localSettings.setOption(ClientConfigProperties.serverSetting(ServerSettings.RESULT_OVERFLOW_MODE),
-                    ServerSettings.RESULT_OVERFLOW_MODE_BREAK);
-        } else {
-            // overriding potential client settings (set thru connection setup)
-            // there is no no limit value so we use very large limit.
-            localSettings.setOption(ClientConfigProperties.serverSetting(ServerSettings.MAX_RESULT_ROWS), Long.MAX_VALUE);
-            localSettings.setOption(ClientConfigProperties.serverSetting(ServerSettings.RESULT_OVERFLOW_MODE),
-                    ServerSettings.RESULT_OVERFLOW_MODE_BREAK);
+
+        if (connection.getJdbcConfig().isFlagSet(DriverProperties.USE_MAX_RESULT_ROWS)) {
+            // This method override user set overflow mode on purpose:
+            // 1. Spec clearly states that after calling this method with a limit > 0 all rows over limit are dropped.
+            // 2. Calling this method should not cause throwing exception for future queries what only `break` can guarantee
+            // 3. If user wants different behavior then they are can use connection properties.
+            if (max > 0) {
+                localSettings.setOption(ClientConfigProperties.serverSetting(ServerSettings.MAX_RESULT_ROWS), maxRows);
+                localSettings.setOption(ClientConfigProperties.serverSetting(ServerSettings.RESULT_OVERFLOW_MODE),
+                        ServerSettings.RESULT_OVERFLOW_MODE_BREAK);
+            } else {
+                // overriding potential client settings (set thru connection setup)
+                // there is no no limit value so we use very large limit.
+                localSettings.setOption(ClientConfigProperties.serverSetting(ServerSettings.MAX_RESULT_ROWS), Long.MAX_VALUE);
+                localSettings.setOption(ClientConfigProperties.serverSetting(ServerSettings.RESULT_OVERFLOW_MODE),
+                        ServerSettings.RESULT_OVERFLOW_MODE_BREAK);
+            }
         }
     }
 

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

@@ -309,6 +309,10 @@ public static String getDefaultClientName() {
     }
 
     public boolean isBetaFeatureEnabled(DriverProperties prop) {
+        return isFlagSet(prop);
+    }
+
+    public boolean isFlagSet(DriverProperties prop) {
         String value = driverProperties.getOrDefault(prop.getKey(), prop.getDefaultValue());
         return Boolean.parseBoolean(value);
     }
@@ -318,4 +322,8 @@ private Map<ClickHouseDataType, Class<?>> defaultTypeHintMapping() {
         mapping.put(ClickHouseDataType.Array, List.class);
         return mapping;
     }
+
+    public boolean useMaxResultRows() {
+        return isFlagSet(DriverProperties.USE_MAX_RESULT_ROWS);
+    }
 }