fixed by index perf. added using ImmutableMap

Author: chernser

client-v2/pom.xml

@@ -82,6 +82,12 @@
             <scope>compile</scope>
         </dependency>
 
+        <!-- https://mvnrepository.com/artifact/com.google.guava/guava -->
+        <dependency>
+            <groupId>com.google.guava</groupId>
+            <artifactId>guava</artifactId>
+            <version>${guava.version}</version>
+        </dependency>
 
         <!-- Test Dependencies -->
         <dependency>

client-v2/src/main/java/com/clickhouse/client/api/metadata/TableSchema.java

@@ -1,7 +1,7 @@
 package com.clickhouse.client.api.metadata;
 
-import com.clickhouse.client.api.ClientException;
 import com.clickhouse.data.ClickHouseColumn;
+import com.google.common.collect.ImmutableMap;
 
 import java.util.ArrayList;
 import java.util.Collections;
@@ -91,6 +91,15 @@ public ClickHouseColumn getColumnByName(String name) {
         return columns.get(nameToIndex(name));
     }
 
+    /**
+     * Returns column by index. Index starts with 1.
+     * @param colIndex - column index;
+     * @return
+     */
+    public ClickHouseColumn getColumnByIndex(int colIndex) {
+        return columns.get(colIndex - 1);
+    }
+
     /**
      * Takes absolute index (starting from 0) and returns corresponding column.
      *
@@ -120,8 +129,13 @@ public int nameToColumnIndex(String name) {
         return nameToIndex(name) + 1;
     }
 
+    private ImmutableMap<String, Integer> colIndexes = null;
+
     public int nameToIndex(String name) {
-        Integer index = colIndex.get(name);
+        if (colIndexes == null) {
+            colIndexes = ImmutableMap.copyOf(colIndex);
+        }
+        Integer index = colIndexes.get(name);
         if (index == null) {
             throw new NoSuchColumnException("Result has no column with name '" + name + "'");
         }

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

@@ -431,7 +431,7 @@ public ResultSetMetaData getMetaData() throws SQLException {
 
     @Override
     public Object getObject(int columnIndex) throws SQLException {
-        return getObject(columnIndexToName(columnIndex));
+        return getObject(columnIndex, JdbcUtils.convertToJavaClass(getSchema().getColumnByIndex(columnIndex).getDataType()));
     }
 
     @Override
@@ -959,7 +959,7 @@ public Statement getStatement() throws SQLException {
 
     @Override
     public Object getObject(int columnIndex, Map<String, Class<?>> map) throws SQLException {
-        return getObject(columnIndexToName(columnIndex), map);
+        return getObject(columnIndex, map.get(JdbcUtils.convertToSqlType(getSchema().getColumnByIndex(columnIndex).getDataType())));
     }
 
     @Override
@@ -1493,7 +1493,24 @@ public void updateNClob(String columnLabel, Reader reader) throws SQLException {
 
     @Override
     public <T> T getObject(int columnIndex, Class<T> type) throws SQLException {
-        return getObject(columnIndexToName(columnIndex), type);
+        checkClosed();
+        try {
+            if (reader.hasValue(columnIndex)) {
+                wasNull = false;
+                if (type == null) {//As a fallback, try to get the value as is
+                    return reader.readValue(columnIndex);
+                }
+
+                return (T) JdbcUtils.convert(reader.readValue(columnIndex), type);
+            } else {
+                wasNull = true;
+                return null;
+            }
+        } catch (Exception e) {
+            throw ExceptionUtils.toSqlState(String.format("Method: getObject(\"%s\", %s) encountered an exception.",
+                            reader.getSchema().columnIndexToName(columnIndex), type),
+                    String.format("SQL: [%s]", parentStatement.getLastSql()), e);
+        }
     }
 
     @Override

performance/src/test/com/clickhouse/benchmark/clients/JDBCQuery.java

@@ -1,5 +1,6 @@
 package com.clickhouse.benchmark.clients;
 
+import com.clickhouse.data.ClickHouseColumn;
 import org.openjdk.jmh.annotations.Benchmark;
 import org.openjdk.jmh.infra.Blackhole;
 import org.slf4j.Logger;
@@ -9,19 +10,22 @@
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.sql.Statement;
+import java.util.List;
+import java.util.stream.Collectors;
 
 import static com.clickhouse.benchmark.BenchmarkRunner.getSelectQuery;
 
 public class JDBCQuery extends BenchmarkBase {
     private static final Logger LOGGER = LoggerFactory.getLogger(JDBCQuery.class);
+
     void selectData(Connection connection, DataState dataState, Blackhole blackhole) throws SQLException {
         String sql = getSelectQuery(dataState.tableNameFilled);
-        try (Statement stmt = connection.createStatement()) {
-            try (ResultSet rs = stmt.executeQuery(sql)) {
-                while (rs.next()) {
-                    for (int i = 1; i <= dataState.dataSet.getSchema().getColumns().size(); i++) {
-                        blackhole.consume(rs.getObject(i));
-                    }
+        try (Statement stmt = connection.createStatement();
+             ResultSet rs = stmt.executeQuery(sql)) {
+            int nCol = dataState.dataSet.getSchema().getColumns().size();
+            while (rs.next()) {
+                for (int i = 1; i <= nCol; i++) {
+                    blackhole.consume(rs.getObject(i));
                 }
             }
         }
@@ -37,4 +41,26 @@ public void selectJDBCV2(DataState dataState, Blackhole blackhole) throws SQLExc
         selectData(jdbcV2, dataState, blackhole);
     }
 
+    void selectDataUseNames(Connection connection, DataState dataState, Blackhole blackhole) throws SQLException {
+        String sql = getSelectQuery(dataState.tableNameFilled);
+        List<String> columnNames = dataState.dataSet.getSchema().getColumns().stream().map(ClickHouseColumn::getColumnName).collect(Collectors.toList());
+        try (Statement stmt = connection.createStatement();
+             ResultSet rs = stmt.executeQuery(sql)) {
+            while (rs.next()) {
+                for (int i = 0; i < columnNames.size(); i++) {
+                    blackhole.consume(rs.getObject(columnNames.get(i)));
+                }
+            }
+        }
+    }
+
+    @Benchmark
+    public void selectJDBCV1UseNames(DataState dataState, Blackhole blackhole) throws SQLException {
+        selectDataUseNames(jdbcV1, dataState, blackhole);
+    }
+
+    @Benchmark
+    public void selectJDBCV2UseName(DataState dataState, Blackhole blackhole) throws SQLException {
+        selectDataUseNames(jdbcV2, dataState, blackhole);
+    }
 }

pom.xml

@@ -144,6 +144,7 @@
         <versions-plugin.version>2.16.0</versions-plugin.version>
         <resource-plugin.version>3.3.1</resource-plugin.version>
         <jmh.version>1.37</jmh.version>
+        <guava.version>33.4.6-jre</guava.version>
 
         <minJdk>1.8</minJdk>
         <skipTests>false</skipTests>