fix(bigquery): Remove ReadAPI bypass in executeSelect()

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

@@ -476,22 +476,29 @@ private BigQueryResult queryRpc(
     }
 
     // Query finished running and we can paginate all the results
-    if (results.getJobComplete() && results.getSchema() != null) {
+    // Results should be read using the high throughput read API if sufficiently large.
+    boolean resultsLargeEnoughForReadApi =
+        connectionSettings.getUseReadAPI()
+            && results.getTotalRows() != null
+            && results.getTotalRows().longValue() > connectionSettings.getMinResultSize();
+    if (results.getJobComplete() && results.getSchema() != null && !resultsLargeEnoughForReadApi) {
       return processQueryResponseResults(results);
     } else {
-      // Query is long-running (> 10s) and hasn't completed yet, or query completed but didn't
-      // return the schema, fallback to jobs.insert path. Some operations don't return the schema
-      // and can be optimized here, but this is left as future work.
-      Long totalRows = results.getTotalRows() == null ? null : results.getTotalRows().longValue();
-      Long pageRows = results.getRows() == null ? null : (long) (results.getRows().size());
+      // Query is long-running (> 10s) and hasn't completed yet, query completed but didn't
+      // return the schema, or results are sufficiently large to use the high throughput read API,
+      // fallback to jobs.insert path. Some operations don't return the schema and can be optimized
+      // here, but this is left as future work.
+      JobId jobId = JobId.fromPb(results.getJobReference());
+      GetQueryResultsResponse firstPage = getQueryResultsFirstPage(jobId);
+      Long totalRows =
+          firstPage.getTotalRows() == null ? null : firstPage.getTotalRows().longValue();
+      Long pageRows = firstPage.getRows() == null ? null : (long) (firstPage.getRows().size());
       logger.log(
           Level.WARNING,
           "\n"
               + String.format(
                   "results.getJobComplete(): %s, isSchemaNull: %s , totalRows: %s, pageRows: %s",
                   results.getJobComplete(), results.getSchema() == null, totalRows, pageRows));
-      JobId jobId = JobId.fromPb(results.getJobReference());
-      GetQueryResultsResponse firstPage = getQueryResultsFirstPage(jobId);
       return getSubsequentQueryResultsWithJob(
           totalRows, pageRows, jobId, firstPage, hasQueryParameters);
     }
@@ -996,6 +1003,7 @@ BigQueryResult highThroughPutRead(
           schema);
 
       logger.log(Level.INFO, "\n Using BigQuery Read API");
+      stats.getQueryStatistics().setUseReadApi(true);
       return new BigQueryResultImpl<BigQueryResultImpl.Row>(schema, totalRows, bufferRow, stats);
 
     } catch (IOException e) {

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

@@ -27,6 +27,7 @@
 import com.google.auto.value.AutoValue;
 import com.google.cloud.StringEnumType;
 import com.google.cloud.StringEnumValue;
+import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Function;
 import com.google.common.base.MoreObjects;
 import com.google.common.base.MoreObjects.ToStringHelper;
@@ -396,6 +397,7 @@ public static class QueryStatistics extends JobStatistics {
     private final BiEngineStats biEngineStats;
     private final Integer billingTier;
     private final Boolean cacheHit;
+    private Boolean useReadApi;
     private final String ddlOperationPerformed;
     private final TableId ddlTargetTable;
     private final RoutineId ddlTargetRoutine;
@@ -796,6 +798,7 @@ private QueryStatistics(Builder builder) {
       this.biEngineStats = builder.biEngineStats;
       this.billingTier = builder.billingTier;
       this.cacheHit = builder.cacheHit;
+      this.useReadApi = false;
       this.ddlOperationPerformed = builder.ddlOperationPerformed;
       this.ddlTargetTable = builder.ddlTargetTable;
       this.ddlTargetRoutine = builder.ddlTargetRoutine;
@@ -835,6 +838,18 @@ public Boolean getCacheHit() {
       return cacheHit;
     }
 
+    /** Returns whether the query result is read from the high throughput ReadAPI. */
+    @VisibleForTesting
+    public Boolean getUseReadApi() {
+      return useReadApi;
+    }
+
+    /** Sets internal state to reflect the use of the high throughput ReadAPI. */
+    @VisibleForTesting
+    public void setUseReadApi(Boolean useReadApi) {
+      this.useReadApi = useReadApi;
+    }
+
     /** [BETA] For DDL queries, returns the operation applied to the DDL target table. */
     public String getDdlOperationPerformed() {
       return ddlOperationPerformed;

google-cloud-bigquery/src/test/java/com/google/cloud/bigquery/it/ITBigQueryTest.java

@@ -3489,6 +3489,63 @@ public void testExecuteSelectDefaultConnectionSettings() throws SQLException {
     String query = "SELECT corpus FROM `bigquery-public-data.samples.shakespeare` GROUP BY corpus;";
     BigQueryResult bigQueryResult = connection.executeSelect(query);
     assertEquals(42, bigQueryResult.getTotalRows());
+    assertFalse(bigQueryResult.getBigQueryResultStats().getQueryStatistics().getUseReadApi());
+  }
+
+  @Test
+  public void testExecuteSelectWithReadApi() throws SQLException {
+    final int rowLimit = 5000;
+    final String QUERY =
+        "SELECT * FROM bigquery-public-data.new_york_taxi_trips.tlc_yellow_trips_2017 LIMIT %s";
+    // Job timeout is somewhat arbitrary - just ensures that fast query is not used.
+    // min result size and page row count ratio ensure that the ReadAPI is used.
+    ConnectionSettings connectionSettingsReadAPIEnabledFastQueryDisabled =
+        ConnectionSettings.newBuilder()
+            .setUseReadAPI(true)
+            .setJobTimeoutMs(Long.MAX_VALUE)
+            .setMinResultSize(500)
+            .setTotalToPageRowCountRatio(1)
+            .build();
+
+    Connection connectionReadAPIEnabled =
+        bigquery.createConnection(connectionSettingsReadAPIEnabledFastQueryDisabled);
+
+    String selectQuery = String.format(QUERY, rowLimit);
+
+    BigQueryResult bigQueryResultSet = connectionReadAPIEnabled.executeSelect(selectQuery);
+    ResultSet rs = bigQueryResultSet.getResultSet();
+    // Paginate results to avoid an InterruptedException
+    while (rs.next()) {}
+
+    assertTrue(bigQueryResultSet.getBigQueryResultStats().getQueryStatistics().getUseReadApi());
+    connectionReadAPIEnabled.close();
+  }
+
+  @Test
+  public void testExecuteSelectWithFastQueryReadApi() throws SQLException {
+    final int rowLimit = 5000;
+    final String QUERY =
+        "SELECT * FROM bigquery-public-data.new_york_taxi_trips.tlc_yellow_trips_2017 LIMIT %s";
+    // min result size and page row count ratio ensure that the ReadAPI is used.
+    ConnectionSettings connectionSettingsReadAPIEnabledFastQueryDisabled =
+        ConnectionSettings.newBuilder()
+            .setUseReadAPI(true)
+            .setMinResultSize(500)
+            .setTotalToPageRowCountRatio(1)
+            .build();
+
+    Connection connectionReadAPIEnabled =
+        bigquery.createConnection(connectionSettingsReadAPIEnabledFastQueryDisabled);
+
+    String selectQuery = String.format(QUERY, rowLimit);
+
+    BigQueryResult bigQueryResultSet = connectionReadAPIEnabled.executeSelect(selectQuery);
+    ResultSet rs = bigQueryResultSet.getResultSet();
+    // Paginate results to avoid an InterruptedException
+    while (rs.next()) {}
+
+    assertTrue(bigQueryResultSet.getBigQueryResultStats().getQueryStatistics().getUseReadApi());
+    connectionReadAPIEnabled.close();
   }
 
   @Test
@@ -3522,6 +3579,7 @@ public void testExecuteSelectWithCredentials() throws SQLException {
             + TABLE_ID_LARGE.getTable(); // Large query result is needed to use BigQueryReadClient.
     BigQueryResult bigQueryResult = connectionGoodCredentials.executeSelect(query);
     assertEquals(313348, bigQueryResult.getTotalRows());
+    assertTrue(bigQueryResult.getBigQueryResultStats().getQueryStatistics().getUseReadApi());
 
     // Scenario 2.
     // Create a new bigQuery object but explicitly an invalid credential.