Disable Object Reuse By Default

clickhouse-client/src/main/java/com/clickhouse/client/ClickHouseRequest.java

@@ -1767,6 +1767,18 @@ public SelfT session(String sessionId, Boolean check, Integer timeout) {
         return (SelfT) this;
     }
 
+    /**
+     * Enable object reuse during result collection, resulting in better memmory efficiency.
+     * WARNING: If you plan to pass the underlying {@link com.clickhouse.data.ClickHouseRecord} back without
+     * intermediate extraction, this object will potentially be overwritten with the last seen value of the stream.
+     * @return the request with object reuse enabled
+     */
+    @SuppressWarnings("unchecked")
+    public SelfT reuseObjects() {
+        option(ClickHouseClientOption.REUSE_VALUE_WRAPPER, "true");
+        return (SelfT) this;
+    }
+
     /**
      * Sets a setting. See
      * https://clickhouse.tech/docs/en/operations/settings/settings/ for more

clickhouse-client/src/test/java/com/clickhouse/client/ClientIntegrationTest.java

@@ -440,6 +440,45 @@ public void testOpenCloseClient() throws ClickHouseException {
         }
     }
 
+    @Test(groups = { "integration" })
+    public void testWithObjectReuse() throws ClickHouseException {
+        int numbers = 10;
+        ClickHouseNode server = getServer();
+        try (ClickHouseClient client = getClient();
+             ClickHouseResponse response = newRequest(client, server).query("select * from numbers(10)")
+                     .reuseObjects()
+                     .executeAndWait()) {
+            List<ClickHouseRecord> records = new ArrayList<>(10);
+            response.stream().forEach(records::add);
+            Assert.assertEquals(records.size(), 10);
+            // Verify that all records are the same (object reuse)
+            for (int i = 0; i < numbers; i++) {
+                // All values will be 9 (last seen record)
+                Assert.assertEquals(records.get(i).getValue(0).asInteger(), 9);
+            }
+        }
+    }
+
+
+    @Test(groups = { "integration" })
+    public void testWithoutObjectReuse() throws ClickHouseException {
+        int numbers = 10;
+        ClickHouseNode server = getServer();
+        try (ClickHouseClient client = getClient();
+             ClickHouseResponse response = newRequest(client, server).query("select * from numbers(10)")
+                     .executeAndWait()) {
+            List<ClickHouseRecord> records = new ArrayList<>(10);
+            response.stream().forEach(records::add);
+            Assert.assertEquals(records.size(), 10);
+            // Verify all records are unique (different number)
+            for (int i = 0; i < numbers; i++) {
+                // Numbers will increment correctly, as object reuse is disabled by default
+                Assert.assertEquals(records.get(i).getValue(0).asInteger(), i);
+            }
+
+        }
+    }
+
     @Test(dataProvider = "compressionMatrix", groups = { "integration" })
     public void testCompression(ClickHouseFormat format, ClickHouseBufferingMode bufferingMode, boolean compressRequest,
             boolean compressResponse) throws ClickHouseException {
@@ -850,7 +889,7 @@ public void testQuery() {
                  * while (response.hasError()) { int index = 0; for (ClickHouseColumn c :
                  * columns) { // RawValue v = response.getRawValue(index++); // String v =
                  * response.getValue(index++, String.class) }
-                 * 
+                 *
                  * } byte[] bytes = in.readAllBytes(); String str = new String(bytes);
                  */
             } catch (Exception e) {

clickhouse-data/src/main/java/com/clickhouse/data/ClickHouseDataConfig.java

@@ -146,7 +146,7 @@ public boolean isWidenUnsignedTypes() {
 
     static final ClickHouseFormat DEFAULT_FORMAT = ClickHouseFormat.TabSeparated;
 
-    static final boolean DEFAULT_REUSE_VALUE_WRAPPER = true;
+    static final boolean DEFAULT_REUSE_VALUE_WRAPPER = false;
     static final boolean DEFAULT_USE_BINARY_STRING = false;
     static final boolean DEFAULT_USE_BLOCKING_QUEUE = false;
     static final boolean DEFAULT_USE_COMPILATION = false;