Merge pull request #2365 from FOCONIS/pr/bugfix/cache_exists_queries

Allow caching of exists-queries

ebean-core/src/main/java/io/ebeaninternal/api/SpiQuery.java

@@ -81,6 +81,11 @@ public interface SpiQuery<T> extends Query<T>, SpiQueryFetch, TxnProfileEventCod
      */
     ID_LIST(FIND_ID_LIST, "findIds"),
 
+    /**
+     * Find exists.
+     */
+    EXISTS(FIND_EXISTS, "exists"),
+
     /**
      * Find single attribute.
      */

ebean-core/src/main/java/io/ebeaninternal/api/TxnProfileEventCodes.java

@@ -26,6 +26,7 @@ public interface TxnProfileEventCodes {
   String FIND_MANY = "fm";
   String FIND_ITERATE = "fe";
   String FIND_ID_LIST = "fi";
+  String FIND_EXISTS = "ex";
   String FIND_ATTRIBUTE = "fa";
   String FIND_COUNT = "fc";
   String FIND_SUBQUERY = "fs";

ebean-core/src/main/java/io/ebeaninternal/server/core/DefaultServer.java

@@ -1296,7 +1296,12 @@ public final class DefaultServer implements SpiServer, SpiEbeanServer {
   @Override
   public <T> boolean exists(Query<T> ormQuery, Transaction transaction) {
     Query<T> ormQueryCopy = ormQuery.copy().setMaxRows(1);
-    SpiOrmQueryRequest<?> request = createQueryRequest(Type.ID_LIST, ormQueryCopy, transaction);
+    SpiOrmQueryRequest<?> request = createQueryRequest(Type.EXISTS, ormQueryCopy, transaction);
+    List<Object> ids = request.getFromQueryCache();
+    if (ids != null) {
+      return !ids.isEmpty();
+    }
+
     try {
       request.initTransIfRequired();
       return !request.findIds().isEmpty();

ebean-test/src/test/java/org/tests/cache/TestQueryCache.java

@@ -16,7 +16,10 @@ import java.util.List;
 import java.util.function.Consumer;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotSame;
+import static org.junit.jupiter.api.Assertions.assertSame;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 public class TestQueryCache extends BaseTestCase {
 
@@ -126,15 +129,52 @@ public class TestQueryCache extends BaseTestCase {
     // and now, ensure that we hit the database
     LoggedSql.start();
     int count2 = DB.find(EColAB.class)
-        .setUseQueryCache(CacheMode.OFF)
-        .where()
-        .eq("columnB", "count")
-        .findCount();
+      .setUseQueryCache(CacheMode.OFF)
+      .where()
+      .eq("columnB", "count")
+      .findCount();
     assertThat(count2).isEqualTo(count1);
     sql = LoggedSql.stop();
     assertThat(sql).hasSize(1);
   }
 
+  @Test
+  public void exists() {
+
+    new EColAB("06", "exists").save();
+    new EColAB("07", "exists").save();
+
+    LoggedSql.start();
+
+    boolean exists0 = DB.find(EColAB.class)
+      .setUseQueryCache(CacheMode.ON)
+      .where()
+      .eq("columnB", "exists")
+      .exists();
+
+    boolean exists1 = DB.find(EColAB.class)
+      .setUseQueryCache(CacheMode.ON)
+      .where()
+      .eq("columnB", "exists")
+      .exists();
+
+    List<String> sql = LoggedSql.stop();
+
+    assertThat(exists0).isEqualTo(exists1);
+    assertThat(sql).hasSize(1);
+
+    // and now, ensure that we hit the database
+    LoggedSql.start();
+    boolean exists2 = DB.find(EColAB.class)
+      .setUseQueryCache(CacheMode.OFF)
+      .where()
+      .eq("columnB", "exists")
+      .exists();
+    assertThat(exists2).isEqualTo(exists1);
+    sql = LoggedSql.stop();
+    assertThat(sql).hasSize(1);
+  }
+
   @Test
   public void findCountDifferentQueries() {