#2089 - Postgres - Use NO KEY with FOR UPDATE clauses with Postgres

ebean-core/src/test/java/org/tests/basic/TestQueryForUpdate.java

@@ -21,7 +21,6 @@ import static org.junit.Assert.assertTrue;
 
 public class TestQueryForUpdate extends BaseTestCase {
 
-
   @Test
   @ForPlatform({Platform.H2, Platform.ORACLE, Platform.POSTGRES, Platform.SQLSERVER, Platform.MYSQL, Platform.MARIADB})
   public void testForUpdate() {
@@ -35,6 +34,8 @@ public class TestQueryForUpdate extends BaseTestCase {
     query.findList();
     if (isSqlServer()) {
       assertThat(sqlOf(query)).contains("with (updlock)");
+    } else if (isPostgres()) {
+      assertThat(sqlOf(query)).contains("for no key update");
     } else {
       assertThat(sqlOf(query)).contains("for update");
     }
@@ -67,7 +68,11 @@ public class TestQueryForUpdate extends BaseTestCase {
       if (isH2() || isPostgres()) {
         assertSql(sql.get(0)).contains("from e_basic t0 where t0.id =");
         assertSql(sql.get(1)).contains("from e_basic t0 where t0.id =");
-        assertSql(sql.get(1)).contains("for update");
+        if (isPostgres()) {
+          assertSql(sql.get(1)).contains("for no key update");
+        } else {
+          assertSql(sql.get(1)).contains("for update");
+        }
       }
 
       transaction.end();
@@ -91,6 +96,8 @@ public class TestQueryForUpdate extends BaseTestCase {
       assertThat(sqlOf(query)).contains("for update");
     } else if (isSqlServer()) {
       assertThat(sqlOf(query)).contains("with (updlock,nowait)");
+    } else if (isPostgres()) {
+      assertThat(sqlOf(query)).contains("for no key update nowait");
     } else {
       assertThat(sqlOf(query)).contains("for update nowait");
     }
@@ -116,6 +123,8 @@ public class TestQueryForUpdate extends BaseTestCase {
         assertThat(sqlOf(query)).contains("with (updlock,nowait)");
       } else if (isH2()) {
         assertThat(sqlOf(query)).contains("for update");
+      } else if (isPostgres()) {
+        assertThat(sqlOf(query)).contains("for no key update nowait");
       } else {
         assertThat(sqlOf(query)).contains("for update nowait");
       }

ebean-core/src/test/java/org/tests/basic/TestQueryForUpdatePostgresLock.java

@@ -0,0 +1,86 @@
+package org.tests.basic;
+
+import io.ebean.BaseTestCase;
+import io.ebean.DB;
+import io.ebean.annotation.ForPlatform;
+import io.ebean.annotation.Platform;
+import io.ebean.annotation.Transactional;
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.tests.model.basic.Article;
+import org.tests.model.basic.Section;
+
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class TestQueryForUpdatePostgresLock extends BaseTestCase {
+
+  private static final Logger log = LoggerFactory.getLogger(TestQueryForUpdatePostgresLock.class);
+
+  private long timePreInsert;
+  private long timePostInsert;
+  private long timePreLock;
+  private long timePostLock;
+
+  @Test
+  @ForPlatform(Platform.POSTGRES)
+  public void testForUpdatePostgresLock() throws InterruptedException {
+
+    Article article = new Article("lockTest", "auth");
+    DB.save(article);
+    final Integer id = article.getId();
+
+    ExecutorService exec = Executors.newFixedThreadPool(2);
+    exec.submit(() -> lockArticle(id));
+    exec.submit(() -> insertSection(id));
+    exec.awaitTermination(2, TimeUnit.SECONDS);
+    exec.shutdown();
+
+    // assert the lock was obtained before the insert was attempted
+    assertThat(timePreLock).isLessThan(timePreInsert);
+    // assert that the insert wasn't waiting on the lock to complete
+    assertThat(timePostInsert).isLessThan(timePostLock);
+  }
+
+  /**
+   * This holds row lock on article for 1 second.
+   * With FOR NO KEY UPDATE this does not block the insert.
+   */
+  @Transactional
+  private void lockArticle(Integer id) {
+    timePreLock = System.currentTimeMillis();
+    log.info("lock start");
+    DB.find(Article.class).setId(id).forUpdate().findOne();
+    sleep(1000);
+    timePostLock = System.currentTimeMillis();
+    log.info("lock done");
+  }
+
+  /**
+   * This inserts with FK to the article that is locked.
+   * With FOR NO KEY UPDATE this insert does not wait on the lock.
+   */
+  @Transactional
+  private void insertSection(Integer id) {
+    sleep(100);
+    log.info("insert start");
+    timePreInsert = System.currentTimeMillis();
+    Section section = new Section();
+    section.setArticle(DB.getReference(Article.class, id));
+    DB.save(section);
+    timePostInsert = System.currentTimeMillis();
+    log.info("inserted");
+  }
+
+  private void sleep(int millis) {
+    try {
+      Thread.sleep(millis);
+    } catch (InterruptedException e) {
+      throw new RuntimeException(e);
+    }
+  }
+}