reuse shrink constants from RowHelper

Author: zhongheng.gy

paimon-common/src/main/java/org/apache/paimon/data/RowHelper.java

@@ -40,15 +40,15 @@ public class RowHelper implements Serializable {
      * Maximum retained reuse buffer size in bytes. Buffers exceeding this cap are eligible for
      * release when the shrink ratio condition is also met.
      */
-    private static final int MAX_RETAINED_REUSE_BUFFER_SIZE = 4 * 1024 * 1024; // 4MB
+    public static final int MAX_RETAINED_REUSE_BUFFER_SIZE = 4 * 1024 * 1024; // 4MB
 
     /**
      * Shrink ratio for hysteresis. The buffer is released only when its capacity exceeds {@link
      * #MAX_RETAINED_REUSE_BUFFER_SIZE} AND is more than {@code SHRINK_RATIO} times the current
      * row's size. This avoids thrashing for sustained medium-to-large records while still releasing
      * after a spike (e.g. 100MB buffer with 5MB rows → 20x > 4x → release).
      */
-    private static final int SHRINK_RATIO = 4;
+    public static final int SHRINK_RATIO = 4;
 
     private final FieldGetter[] fieldGetters;
     private final ValueSetter[] valueSetters;

paimon-common/src/main/java/org/apache/paimon/data/serializer/BinaryRowSerializer.java

@@ -21,6 +21,7 @@
 import org.apache.paimon.data.AbstractPagedInputView;
 import org.apache.paimon.data.AbstractPagedOutputView;
 import org.apache.paimon.data.BinaryRow;
+import org.apache.paimon.data.RowHelper;
 import org.apache.paimon.io.DataInputView;
 import org.apache.paimon.io.DataOutputView;
 import org.apache.paimon.memory.MemorySegment;
@@ -80,19 +81,6 @@ public BinaryRow deserialize(DataInputView source) throws IOException {
         return row;
     }
 
-    /**
-     * Maximum retained reuse buffer size in bytes. Buffers exceeding this cap are eligible for
-     * shrinking when the shrink ratio condition is also met.
-     */
-    private static final int MAX_RETAINED_REUSE_BUFFER_SIZE = 4 * 1024 * 1024; // 4MB
-
-    /**
-     * Shrink ratio. The buffer is reallocated only when its size exceeds {@link
-     * #MAX_RETAINED_REUSE_BUFFER_SIZE} AND is more than {@code SHRINK_RATIO} times the current
-     * record length.
-     */
-    private static final int SHRINK_RATIO = 4;
-
     public BinaryRow deserialize(BinaryRow reuse, DataInputView source) throws IOException {
         MemorySegment[] segments = reuse.getSegments();
         checkArgument(
@@ -103,8 +91,8 @@ public BinaryRow deserialize(BinaryRow reuse, DataInputView source) throws IOExc
         if (segments == null || segments[0].size() < length) {
             // Need a larger buffer
             segments = new MemorySegment[] {MemorySegment.wrap(new byte[length])};
-        } else if (segments[0].size() > MAX_RETAINED_REUSE_BUFFER_SIZE
-                && segments[0].size() > (long) length * SHRINK_RATIO) {
+        } else if (segments[0].size() > RowHelper.MAX_RETAINED_REUSE_BUFFER_SIZE
+                && segments[0].size() > (long) length * RowHelper.SHRINK_RATIO) {
             segments = new MemorySegment[] {MemorySegment.wrap(new byte[length])};
         }
         source.readFully(segments[0].getArray(), 0, length);