perf(bigquery): [T2-4] avoid defensive HashMap copy for ImmutableMap in InsertAllRequest.RowToInsert

java-bigquery/google-cloud-bigquery/src/main/java/com/google/cloud/bigquery/InsertAllRequest.java

@@ -85,12 +85,20 @@ public static class RowToInsert implements Serializable {
     private final Map<String, Object> content;
 
     RowToInsert(String id, Map<String, ?> content) {
+      this(id, content, true);
+    }
+
+    private RowToInsert(String id, Map<String, ?> content, boolean defensiveCopy) {
       this.id = id;
 
       if (content instanceof ImmutableMap) {
         this.content = ImmutableMap.copyOf(content);
-      } else {
+      } else if (content.isEmpty()) {
+        this.content = ImmutableMap.of();
+      } else if (defensiveCopy) {
         this.content = Collections.unmodifiableMap(new HashMap<>(content));
+      } else {
+        this.content = Collections.unmodifiableMap(content);
       }
     }
 
@@ -153,6 +161,34 @@ public static RowToInsert of(String id, Map<String, ?> content) {
     public static RowToInsert of(Map<String, ?> content) {
       return new RowToInsert(null, checkNotNull(content));
     }
+
+    /**
+     * Creates a row to be inserted with associated id without defensively copying {@code content}.
+     *
+     * <p>The caller must not mutate {@code content} after passing it to this method. The returned
+     * row wraps {@code content} in an unmodifiable view when it is not already an {@link
+     * ImmutableMap}.
+     *
+     * @param id id of the row, used to identify duplicates
+     * @param content the actual content of the row
+     */
+    public static RowToInsert ofWithoutCopy(String id, Map<String, ?> content) {
+      return new RowToInsert(checkNotNull(id), checkNotNull(content), false);
+    }
+
+    /**
+     * Creates a row to be inserted without associated id and without defensively copying {@code
+     * content}.
+     *
+     * <p>The caller must not mutate {@code content} after passing it to this method. The returned
+     * row wraps {@code content} in an unmodifiable view when it is not already an {@link
+     * ImmutableMap}.
+     *
+     * @param content the actual content of the row
+     */
+    public static RowToInsert ofWithoutCopy(Map<String, ?> content) {
+      return new RowToInsert(null, checkNotNull(content), false);
+    }
   }
 
   public static final class Builder {
@@ -243,6 +279,27 @@ public Builder addRow(Map<String, ?> content) {
       return this;
     }
 
+    /**
+     * Adds a row to be inserted with associated id without defensively copying {@code content}.
+     *
+     * <p>The caller must not mutate {@code content} after passing it to this method.
+     */
+    public Builder addRowWithoutCopy(String id, Map<String, ?> content) {
+      addRow(RowToInsert.ofWithoutCopy(id, content));
+      return this;
+    }
+
+    /**
+     * Adds a row to be inserted without an associated id and without defensively copying {@code
+     * content}.
+     *
+     * <p>The caller must not mutate {@code content} after passing it to this method.
+     */
+    public Builder addRowWithoutCopy(Map<String, ?> content) {
+      addRow(RowToInsert.ofWithoutCopy(content));
+      return this;
+    }
+
     /**
      * Sets whether to insert all valid rows of a request, even if invalid rows exist. If not set
      * the entire insert request will fail if it contains an invalid row.

java-bigquery/google-cloud-bigquery/src/test/java/com/google/cloud/bigquery/InsertAllRequestTest.java

@@ -229,6 +229,44 @@ public void testNullOK() {
     assertThat(row.getContent()).containsExactly("foo", null);
   }
 
+  @Test
+  public void testWithoutCopy() {
+    Map<String, Object> map1 = new HashMap<>();
+    map1.put("key", "val1");
+    Map<String, Object> map2 = new HashMap<>();
+    map2.put("key", "val2");
+
+    InsertAllRequest.RowToInsert rowWithoutId = InsertAllRequest.RowToInsert.ofWithoutCopy(map1);
+    assertThat(rowWithoutId.getId()).isNull();
+    assertThat(rowWithoutId.getContent()).isEqualTo(CONTENT1);
+    assertThrows(
+        UnsupportedOperationException.class, () -> rowWithoutId.getContent().put("k", "v"));
+
+    InsertAllRequest.RowToInsert rowWithId =
+        InsertAllRequest.RowToInsert.ofWithoutCopy("id1", map1);
+    assertThat(rowWithId.getId()).isEqualTo("id1");
+    assertThat(rowWithId.getContent()).isEqualTo(CONTENT1);
+    assertThrows(UnsupportedOperationException.class, () -> rowWithId.getContent().put("k", "v"));
+
+    InsertAllRequest requestWithoutId =
+        InsertAllRequest.newBuilder(TABLE_ID)
+            .addRowWithoutCopy(map1)
+            .addRowWithoutCopy(map2)
+            .setIgnoreUnknownValues(IGNORE_UNKNOWN_VALUES)
+            .setSkipInvalidRows(SKIP_INVALID_ROWS)
+            .build();
+    compareInsertAllRequest(INSERT_ALL_REQUEST1, requestWithoutId);
+
+    InsertAllRequest requestWithId =
+        InsertAllRequest.newBuilder(TABLE_ID)
+            .addRowWithoutCopy("id1", map1)
+            .addRowWithoutCopy("id2", map2)
+            .setIgnoreUnknownValues(IGNORE_UNKNOWN_VALUES)
+            .setSkipInvalidRows(SKIP_INVALID_ROWS)
+            .build();
+    compareInsertAllRequest(INSERT_ALL_REQUEST3, requestWithId);
+  }
+
   private void compareInsertAllRequest(InsertAllRequest expected, InsertAllRequest value) {
     assertThat(expected).isEqualTo(value);
     assertThat(expected.toString()).isEqualTo(value.toString());