fix(bqjdbc): pass rowsInPage with TableResult (#13238)

b/511229401

This PR introduces the `rowsInPage` metadata to `TableResult` and
ensures it is populated for all pages (both the first page and
subsequent pages fetched via pagination).

Previously, metadata about the number of rows in the page was not easily
accessible or propagated across multiple paginated requests (e.g., when
calling `getNextPage()`). This change:
1. Adds a `rowsInPage` field and builder method to the `@AutoValue`
`TableResult` class.
2. Populates `rowsInPage` during initial page creation in `BigQueryImpl`
and empty results in `Job.java`.
3. Updates `TableResult.getNextPage()` to calculate the size of values
for subsequent pages via `Iterables.size` (which is $O(1)$ for
materialized lists) and sets it on the returned `TableResult` pages.
4. Updates unit test assertions in `TableResultTest.java` and
`SerializationTest.java` to verify that `rowsInPage` is populated and
propagated correctly.

## Key Changes
- **`TableResult.java`**: Added `getRowsInPage()`, builder method
`setRowsInPage()`, and updated `getNextPage()` to pass down the
calculated row count for the next page.
- **`BigQueryImpl.java`**: Set `rowsInPage` on initial query results
page creation.
- **`TableResultTest.java`**: Added assertions to verify that
`rowsInPage` is correctly populated for both the first page and
subsequent pages.

---------

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

Author: Neenu1995

java-bigquery-jdbc/src/main/java/com/google/cloud/bigquery/jdbc/BigQueryStatement.java

@@ -1028,7 +1028,9 @@ private boolean meetsReadRatio(TableResult results) {
       return false;
     }
 
-    long pageSize = querySettings.getMaxResultPerPage();
+    Long rowsInPage = results.getRowsInPage();
+    long pageSize =
+        (rowsInPage != null && rowsInPage > 0) ? rowsInPage : querySettings.getMaxResultPerPage();
 
     // Prevent division by zero due to potential overflows/empty sets:
     if (pageSize <= 0) {

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

@@ -1691,6 +1691,7 @@ && getOptions().getOpenTelemetryTracer() != null) {
           .setSchema(schema)
           .setTotalRows(data.y())
           .setPageNoSchema(data.x())
+          .setRowsInPage((long) Iterables.size(data.x().getValues()))
           .build();
     } finally {
       if (tableDataList != null) {
@@ -2022,6 +2023,7 @@ public com.google.api.services.bigquery.model.QueryResponse call()
           .setJobId(jobId)
           .setQueryId(results.getQueryId())
           .setJobCreationReason(JobCreationReason.fromPb(results.getJobCreationReason()))
+          .setRowsInPage(results.getRows() != null ? (long) results.getRows().size() : 0L)
           .build();
     }
     // only 1 page of result
@@ -2041,6 +2043,7 @@ public com.google.api.services.bigquery.model.QueryResponse call()
             results.getJobReference() != null ? JobId.fromPb(results.getJobReference()) : null)
         .setQueryId(results.getQueryId())
         .setJobCreationReason(JobCreationReason.fromPb(results.getJobCreationReason()))
+        .setRowsInPage(results.getRows() != null ? (long) results.getRows().size() : 0L)
         .build();
   }
 

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

@@ -424,6 +424,7 @@ public TableResult getQueryResults(QueryResultsOption... options)
                 .setJobId(job.getJobId())
                 .setTotalRows(0L)
                 .setPageNoSchema(new PageImpl<FieldValueList>(null, "", null))
+                .setRowsInPage(0L)
                 .build();
         return emptyTableResult;
       }

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

@@ -49,6 +49,8 @@ public abstract static class Builder {
 
     public abstract TableResult.Builder setJobCreationReason(JobCreationReason jobCreationReason);
 
+    abstract TableResult.Builder setRowsInPage(Long rowsInPage);
+
     /** Creates a @code TableResult} object. */
     public abstract TableResult build();
   }
@@ -81,6 +83,10 @@ public static Builder newBuilder() {
   @Nullable
   public abstract JobCreationReason getJobCreationReason();
 
+  /** Returns the number of rows in the current page of results. */
+  @Nullable
+  public abstract Long getRowsInPage();
+
   @Override
   public boolean hasNextPage() {
     return getPageNoSchema().hasNextPage();
@@ -94,12 +100,15 @@ public String getNextPageToken() {
   @Override
   public TableResult getNextPage() {
     if (getPageNoSchema().hasNextPage()) {
+      Page<FieldValueList> nextPageNoSchema = getPageNoSchema().getNextPage();
+      long nextRows = (long) Iterables.size(nextPageNoSchema.getValues());
       return TableResult.newBuilder()
           .setSchema(getSchema())
           .setTotalRows(getTotalRows())
-          .setPageNoSchema(getPageNoSchema().getNextPage())
+          .setPageNoSchema(nextPageNoSchema)
           .setQueryId(getQueryId())
           .setJobCreationReason(getJobCreationReason())
+          .setRowsInPage(nextRows)
           .build();
     }
     return null;
@@ -137,12 +146,14 @@ public String toString() {
         .add("totalRows", getTotalRows())
         .add("cursor", getNextPageToken())
         .add("queryId", getQueryId())
+        .add("rowsInPage", getRowsInPage())
         .toString();
   }
 
   @Override
   public final int hashCode() {
-    return Objects.hash(getPageNoSchema(), getSchema(), getTotalRows(), getQueryId());
+    return Objects.hash(
+        getPageNoSchema(), getSchema(), getTotalRows(), getQueryId(), getRowsInPage());
   }
 
   @Override
@@ -158,6 +169,7 @@ public final boolean equals(Object obj) {
         && Iterators.elementsEqual(getValues().iterator(), response.getValues().iterator())
         && Objects.equals(getSchema(), response.getSchema())
         && getTotalRows() == response.getTotalRows()
-        && getQueryId() == response.getQueryId();
+        && Objects.equals(getQueryId(), response.getQueryId())
+        && Objects.equals(getRowsInPage(), response.getRowsInPage());
   }
 }

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

@@ -210,6 +210,7 @@ public class SerializationTest extends BaseSerializationTest {
           .setSchema(Schema.of())
           .setTotalRows(0L)
           .setPageNoSchema(new PageImpl(null, "", ImmutableList.of()))
+          .setRowsInPage(0L)
           .build();
   private static final BigQuery BIGQUERY =
       BigQueryOptions.newBuilder().setProjectId("p1").build().getService();

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

@@ -54,10 +54,15 @@ private static FieldValueList newFieldValueList(String s) {
   @Test
   void testNullSchema() {
     TableResult result =
-        TableResult.newBuilder().setTotalRows(3L).setPageNoSchema(INNER_PAGE_0).build();
+        TableResult.newBuilder()
+            .setTotalRows(3L)
+            .setPageNoSchema(INNER_PAGE_0)
+            .setRowsInPage(2L)
+            .build();
     assertThat(result.getSchema()).isNull();
     assertThat(result.hasNextPage()).isTrue();
     assertThat(result.getNextPageToken()).isNotNull();
+    assertThat(result.getRowsInPage()).isEqualTo(2L);
     assertThat(result.getValues())
         .containsExactly(newFieldValueList("0"), newFieldValueList("1"))
         .inOrder();
@@ -66,6 +71,7 @@ void testNullSchema() {
     assertThat(next.getSchema()).isNull();
     assertThat(next.hasNextPage()).isFalse();
     assertThat(next.getNextPageToken()).isNull();
+    assertThat(next.getRowsInPage()).isEqualTo(1L);
     assertThat(next.getValues()).containsExactly(newFieldValueList("2"));
     assertThat(next.getNextPage()).isNull();
 
@@ -81,10 +87,12 @@ void testSchema() {
             .setSchema(SCHEMA)
             .setTotalRows(3L)
             .setPageNoSchema(INNER_PAGE_0)
+            .setRowsInPage(2L)
             .build();
     assertThat(result.getSchema()).isEqualTo(SCHEMA);
     assertThat(result.hasNextPage()).isTrue();
     assertThat(result.getNextPageToken()).isNotNull();
+    assertThat(result.getRowsInPage()).isEqualTo(2L);
     assertThat(result.getValues())
         .containsExactly(
             newFieldValueList("0").withSchema(SCHEMA.getFields()),
@@ -95,6 +103,7 @@ void testSchema() {
     assertThat(next.getSchema()).isEqualTo(SCHEMA);
     assertThat(next.hasNextPage()).isFalse();
     assertThat(next.getNextPageToken()).isNull();
+    assertThat(next.getRowsInPage()).isEqualTo(1L);
     assertThat(next.getValues())
         .containsExactly(newFieldValueList("2").withSchema(SCHEMA.getFields()));
     assertThat(next.getNextPage()).isNull();