private void testSavepoint() {
    MVStore s = MVStore.open(null);
    TransactionStore ts = new TransactionStore(s);
    Transaction tx;
    TransactionMap<String, String> m;

    tx = ts.begin();
    m = tx.openMap("test");
    m.put("1", "Hello");
    m.put("2", "World");
    m.put("1", "Hallo");
    m.remove("2");
    m.put("3", "!");
    long logId = tx.setSavepoint();
    m.put("1", "Hi");
    m.put("2", ".");
    m.remove("3");
    tx.rollbackToSavepoint(logId);
    assertEquals("Hallo", m.get("1"));
    assertNull(m.get("2"));
    assertEquals("!", m.get("3"));
    tx.rollback();

    tx = ts.begin();
    m = tx.openMap("test");
    assertNull(m.get("1"));
    assertNull(m.get("2"));
    assertNull(m.get("3"));

    ts.close();
    s.close();
  }
  private void testKeyIterator() {
    MVStore s = MVStore.open(null);
    TransactionStore ts = new TransactionStore(s);
    Transaction tx, tx2;
    TransactionMap<String, String> m, m2;
    Iterator<String> it, it2;

    tx = ts.begin();
    m = tx.openMap("test");
    m.put("1", "Hello");
    m.put("2", "World");
    m.put("3", ".");
    tx.commit();

    tx2 = ts.begin();
    m2 = tx2.openMap("test");
    m2.remove("2");
    m2.put("3", "!");
    m2.put("4", "?");

    tx = ts.begin();
    m = tx.openMap("test");
    it = m.keyIterator(null);
    assertTrue(it.hasNext());
    assertEquals("1", it.next());
    assertTrue(it.hasNext());
    assertEquals("2", it.next());
    assertTrue(it.hasNext());
    assertEquals("3", it.next());
    assertFalse(it.hasNext());

    it2 = m2.keyIterator(null);
    assertTrue(it2.hasNext());
    assertEquals("1", it2.next());
    assertTrue(it2.hasNext());
    assertEquals("3", it2.next());
    assertTrue(it2.hasNext());
    assertEquals("4", it2.next());
    assertFalse(it2.hasNext());

    s.close();
  }
 /** Roll the transaction back. Afterwards, this transaction is closed. */
 public void rollback() {
   if (status != STATUS_CLOSED) {
     store.rollback(this, logId);
     status = STATUS_CLOSED;
   }
 }
 /** Commit the transaction. Afterwards, this transaction is closed. */
 public void commit() {
   if (status != STATUS_CLOSED) {
     store.commit(this, logId);
     status = STATUS_CLOSED;
   }
 }
 /**
  * Prepare the transaction. Afterwards, the transaction can only be committed or rolled back.
  */
 public void prepare() {
   checkOpen();
   store.prepare(this);
   status = STATUS_PREPARED;
 }
 /**
  * Roll back to the given savepoint. This is only allowed if the transaction is open.
  *
  * @param savepointId the savepoint id
  */
 public void rollbackToSavepoint(long savepointId) {
   checkOpen();
   store.rollbackTo(this, this.logId, savepointId);
   this.logId = savepointId;
 }
 /**
  * Add a log entry.
  *
  * @param opType the operation type
  * @param mapId the map id
  * @param key the key
  * @param oldValue the old value
  */
 void log(int opType, int mapId, Object key, Object oldValue) {
   store.log(this, logId++, opType, mapId, key, oldValue);
 }
 /**
  * Set the name of the transaction.
  *
  * @param name the new name
  */
 public void setName(String name) {
   checkOpen();
   store.setTransactionName(this, name);
   this.name = name;
 }
  private void testSingleConnection() {
    MVStore s = MVStore.open(null);

    TransactionStore ts = new TransactionStore(s);

    Transaction tx;
    TransactionMap<String, String> m;

    // add, rollback
    tx = ts.begin();
    m = tx.openMap("test");
    m.put("1", "Hello");
    assertEquals("Hello", m.get("1"));
    m.put("2", "World");
    assertEquals("World", m.get("2"));
    tx.rollback();
    tx = ts.begin();
    m = tx.openMap("test");
    assertNull(m.get("1"));
    assertNull(m.get("2"));

    // add, commit
    tx = ts.begin();
    m = tx.openMap("test");
    m.put("1", "Hello");
    m.put("2", "World");
    assertEquals("Hello", m.get("1"));
    assertEquals("World", m.get("2"));
    tx.commit();
    tx = ts.begin();
    m = tx.openMap("test");
    assertEquals("Hello", m.get("1"));
    assertEquals("World", m.get("2"));

    // update+delete+insert, rollback
    tx = ts.begin();
    m = tx.openMap("test");
    m.put("1", "Hallo");
    m.remove("2");
    m.put("3", "!");
    assertEquals("Hallo", m.get("1"));
    assertNull(m.get("2"));
    assertEquals("!", m.get("3"));
    tx.rollback();
    tx = ts.begin();
    m = tx.openMap("test");
    assertEquals("Hello", m.get("1"));
    assertEquals("World", m.get("2"));
    assertNull(m.get("3"));

    // update+delete+insert, commit
    tx = ts.begin();
    m = tx.openMap("test");
    m.put("1", "Hallo");
    m.remove("2");
    m.put("3", "!");
    assertEquals("Hallo", m.get("1"));
    assertNull(m.get("2"));
    assertEquals("!", m.get("3"));
    tx.commit();
    tx = ts.begin();
    m = tx.openMap("test");
    assertEquals("Hallo", m.get("1"));
    assertNull(m.get("2"));
    assertEquals("!", m.get("3"));

    ts.close();
    s.close();
  }
  private void testConcurrentTransactionsReadCommitted() {
    MVStore s = MVStore.open(null);

    TransactionStore ts = new TransactionStore(s);

    Transaction tx1, tx2;
    TransactionMap<String, String> m1, m2;

    tx1 = ts.begin();
    m1 = tx1.openMap("test");
    m1.put("1", "Hi");
    m1.put("3", ".");
    tx1.commit();

    tx1 = ts.begin();
    m1 = tx1.openMap("test");
    m1.put("1", "Hello");
    m1.put("2", "World");
    m1.remove("3");
    tx1.commit();

    // start new transaction to read old data
    tx2 = ts.begin();
    m2 = tx2.openMap("test");

    // start transaction tx1, update/delete/add
    tx1 = ts.begin();
    m1 = tx1.openMap("test");
    m1.put("1", "Hallo");
    m1.remove("2");
    m1.put("3", "!");

    assertEquals("Hello", m2.get("1"));
    assertEquals("World", m2.get("2"));
    assertNull(m2.get("3"));

    tx1.commit();

    assertEquals("Hallo", m2.get("1"));
    assertNull(m2.get("2"));
    assertEquals("!", m2.get("3"));

    tx1 = ts.begin();
    m1 = tx1.openMap("test");
    m1.put("2", "World");

    assertNull(m2.get("2"));
    assertFalse(m2.tryRemove("2"));
    assertFalse(m2.tryPut("2", "Welt"));

    tx2 = ts.begin();
    m2 = tx2.openMap("test");
    assertNull(m2.get("2"));
    m1.remove("2");
    assertNull(m2.get("2"));
    tx1.commit();

    tx1 = ts.begin();
    m1 = tx1.openMap("test");
    assertNull(m1.get("2"));
    m1.put("2", "World");
    m1.put("2", "Welt");
    tx1.rollback();

    tx1 = ts.begin();
    m1 = tx1.openMap("test");
    assertNull(m1.get("2"));

    ts.close();
    s.close();
  }
  private void testStopWhileCommitting() throws Exception {
    String fileName = getBaseDir() + "/testStopWhileCommitting.h3";
    FileUtils.delete(fileName);
    Random r = new Random(0);

    for (int i = 0; i < 10; ) {
      MVStore s;
      TransactionStore ts;
      Transaction tx;
      TransactionMap<Integer, String> m;

      s = MVStore.open(fileName);
      ts = new TransactionStore(s);
      tx = ts.begin();
      s.setReuseSpace(false);
      m = tx.openMap("test");
      final String value = "x" + i;
      for (int j = 0; j < 1000; j++) {
        m.put(j, value);
      }
      final AtomicInteger state = new AtomicInteger();
      final MVStore store = s;
      final MVMap<Integer, String> other = s.openMap("other");
      Task task =
          new Task() {

            @Override
            public void call() throws Exception {
              for (int i = 0; !stop; i++) {
                state.set(i);
                other.put(i, value);
                store.commit();
              }
            }
          };
      task.execute();
      // wait for the task to start
      while (state.get() < 1) {
        Thread.yield();
      }
      // commit while writing in the task
      tx.commit();
      // wait for the task to stop
      task.get();
      store.close();
      s = MVStore.open(fileName);
      // roll back a bit, until we have some undo log entries
      assertTrue(s.hasMap("undoLog"));
      for (int back = 0; back < 100; back++) {
        int minus = r.nextInt(10);
        s.rollbackTo(Math.max(0, s.getCurrentVersion() - minus));
        MVMap<?, ?> undo = s.openMap("undoLog");
        if (undo.size() > 0) {
          break;
        }
      }
      ts = new TransactionStore(s);
      List<Transaction> list = ts.getOpenTransactions();
      if (list.size() != 0) {
        tx = list.get(0);
        if (tx.getStatus() == Transaction.STATUS_COMMITTING) {
          i++;
        }
      }
      s.close();
      FileUtils.delete(fileName);
      assertFalse(FileUtils.exists(fileName));
    }
  }
  private void testCompareWithPostgreSQL() throws Exception {
    ArrayList<Statement> statements = New.arrayList();
    ArrayList<Transaction> transactions = New.arrayList();
    ArrayList<TransactionMap<Integer, String>> maps = New.arrayList();
    int connectionCount = 3, opCount = 1000, rowCount = 10;
    try {
      Class.forName("org.postgresql.Driver");
      for (int i = 0; i < connectionCount; i++) {
        Connection conn = DriverManager.getConnection("jdbc:postgresql:test", "sa", "sa");
        statements.add(conn.createStatement());
      }
    } catch (Exception e) {
      // database not installed - ok
      return;
    }
    statements.get(0).execute("drop table if exists test cascade");
    statements.get(0).execute("create table test(id int primary key, name varchar(255))");

    MVStore s = MVStore.open(null);
    TransactionStore ts = new TransactionStore(s);
    for (int i = 0; i < connectionCount; i++) {
      Statement stat = statements.get(i);
      // 100 ms to avoid blocking (the test is single threaded)
      stat.execute("set statement_timeout to 100");
      Connection c = stat.getConnection();
      c.setTransactionIsolation(Connection.TRANSACTION_READ_COMMITTED);
      c.setAutoCommit(false);
      Transaction transaction = ts.begin();
      transactions.add(transaction);
      TransactionMap<Integer, String> map;
      map = transaction.openMap("test");
      maps.add(map);
    }
    StringBuilder buff = new StringBuilder();

    Random r = new Random(1);
    try {
      for (int i = 0; i < opCount; i++) {
        int connIndex = r.nextInt(connectionCount);
        Statement stat = statements.get(connIndex);
        Transaction transaction = transactions.get(connIndex);
        TransactionMap<Integer, String> map = maps.get(connIndex);
        if (transaction == null) {
          transaction = ts.begin();
          map = transaction.openMap("test");
          transactions.set(connIndex, transaction);
          maps.set(connIndex, map);

          // read all data, to get a snapshot
          ResultSet rs = stat.executeQuery("select * from test order by id");
          buff.append(i).append(": [" + connIndex + "]=");
          int size = 0;
          while (rs.next()) {
            buff.append(' ');
            int k = rs.getInt(1);
            String v = rs.getString(2);
            buff.append(k).append(':').append(v);
            assertEquals(v, map.get(k));
            size++;
          }
          buff.append('\n');
          if (size != map.sizeAsLong()) {
            assertEquals(size, map.sizeAsLong());
          }
        }
        int x = r.nextInt(rowCount);
        int y = r.nextInt(rowCount);
        buff.append(i).append(": [" + connIndex + "]: ");
        ResultSet rs = null;
        switch (r.nextInt(7)) {
          case 0:
            buff.append("commit");
            stat.getConnection().commit();
            transaction.commit();
            transactions.set(connIndex, null);
            break;
          case 1:
            buff.append("rollback");
            stat.getConnection().rollback();
            transaction.rollback();
            transactions.set(connIndex, null);
            break;
          case 2:
            // insert or update
            String old = map.get(x);
            if (old == null) {
              buff.append("insert " + x + "=" + y);
              if (map.tryPut(x, "" + y)) {
                stat.execute("insert into test values(" + x + ", '" + y + "')");
              } else {
                buff.append(" -> row was locked");
                // the statement would time out in PostgreSQL
                // TODO test sometimes if timeout occurs
              }
            } else {
              buff.append("update " + x + "=" + y + " (old:" + old + ")");
              if (map.tryPut(x, "" + y)) {
                int c = stat.executeUpdate("update test set name = '" + y + "' where id = " + x);
                assertEquals(1, c);
              } else {
                buff.append(" -> row was locked");
                // the statement would time out in PostgreSQL
                // TODO test sometimes if timeout occurs
              }
            }
            break;
          case 3:
            buff.append("delete " + x);
            try {
              int c = stat.executeUpdate("delete from test where id = " + x);
              if (c == 1) {
                map.remove(x);
              } else {
                assertNull(map.get(x));
              }
            } catch (SQLException e) {
              assertTrue(map.get(x) != null);
              assertFalse(map.tryRemove(x));
              // PostgreSQL needs to rollback
              buff.append(" -> rollback");
              stat.getConnection().rollback();
              transaction.rollback();
              transactions.set(connIndex, null);
            }
            break;
          case 4:
          case 5:
          case 6:
            rs = stat.executeQuery("select * from test where id = " + x);
            String expected = rs.next() ? rs.getString(2) : null;
            buff.append("select " + x + "=" + expected);
            assertEquals("i:" + i, expected, map.get(x));
            break;
        }
        buff.append('\n');
      }
    } catch (Exception e) {
      e.printStackTrace();
      fail(buff.toString());
    }
    for (Statement stat : statements) {
      stat.getConnection().close();
    }
    ts.close();
    s.close();
  }
  private void testTwoPhaseCommit() {
    String fileName = getBaseDir() + "/testTwoPhaseCommit.h3";
    FileUtils.delete(fileName);

    MVStore s;
    TransactionStore ts;
    Transaction tx;
    Transaction txOld;
    TransactionMap<String, String> m;
    List<Transaction> list;

    s = MVStore.open(fileName);
    ts = new TransactionStore(s);
    tx = ts.begin();
    assertEquals(null, tx.getName());
    tx.setName("first transaction");
    assertEquals("first transaction", tx.getName());
    assertEquals(0, tx.getId());
    assertEquals(Transaction.STATUS_OPEN, tx.getStatus());
    m = tx.openMap("test");
    m.put("1", "Hello");
    list = ts.getOpenTransactions();
    assertEquals(1, list.size());
    txOld = list.get(0);
    assertTrue(tx.getId() == txOld.getId());
    s.commit();
    ts.close();
    s.close();

    s = MVStore.open(fileName);
    ts = new TransactionStore(s);
    tx = ts.begin();
    assertEquals(1, tx.getId());
    m = tx.openMap("test");
    assertEquals(null, m.get("1"));
    m.put("2", "Hello");
    list = ts.getOpenTransactions();
    assertEquals(2, list.size());
    txOld = list.get(0);
    assertEquals(0, txOld.getId());
    assertEquals(Transaction.STATUS_OPEN, txOld.getStatus());
    assertEquals("first transaction", txOld.getName());
    txOld.prepare();
    assertEquals(Transaction.STATUS_PREPARED, txOld.getStatus());
    s.commit();
    s.close();

    s = MVStore.open(fileName);
    ts = new TransactionStore(s);
    tx = ts.begin();
    m = tx.openMap("test");
    // TransactionStore was not closed, so we lost some ids
    assertEquals(65, tx.getId());
    list = ts.getOpenTransactions();
    assertEquals(2, list.size());
    txOld = list.get(1);
    assertEquals(1, txOld.getId());
    assertEquals(Transaction.STATUS_OPEN, txOld.getStatus());
    assertEquals(null, txOld.getName());
    txOld.rollback();
    txOld = list.get(0);
    assertEquals(0, txOld.getId());
    assertEquals(Transaction.STATUS_PREPARED, txOld.getStatus());
    assertEquals("first transaction", txOld.getName());
    txOld.commit();
    assertEquals("Hello", m.get("1"));
    s.close();

    FileUtils.delete(fileName);
  }
  /**
   * Tests behavior when used for a sequence of SQL statements. Each statement uses a savepoint.
   * Within a statement, changes by the statement itself are not seen; the change is only seen when
   * the statement finished.
   *
   * <p>Update statements that change the key of multiple rows may use delete/add pairs to do so
   * (they don't need to first delete all entries and then re-add them). Trying to add multiple
   * values for the same key is not allowed (an update statement that would result in a duplicate
   * key).
   */
  private void testMultiStatement() {
    MVStore s = MVStore.open(null);
    TransactionStore ts = new TransactionStore(s);
    Transaction tx;
    TransactionMap<String, String> m;
    long startUpdate;

    tx = ts.begin();

    // start of statement
    // create table test
    startUpdate = tx.setSavepoint();
    m = tx.openMap("test");
    m.setSavepoint(startUpdate);

    // start of statement
    // insert into test(id, name) values(1, 'Hello'), (2, 'World')
    startUpdate = tx.setSavepoint();
    m.setSavepoint(startUpdate);
    assertTrue(m.trySet("1", "Hello", true));
    assertTrue(m.trySet("2", "World", true));
    // not seen yet (within the same statement)
    assertNull(m.get("1"));
    assertNull(m.get("2"));

    // start of statement
    startUpdate = tx.setSavepoint();
    // now we see the newest version
    m.setSavepoint(startUpdate);
    assertEquals("Hello", m.get("1"));
    assertEquals("World", m.get("2"));
    // update test set primaryKey = primaryKey + 1
    // (this is usually a tricky case)
    assertEquals("Hello", m.get("1"));
    assertTrue(m.trySet("1", null, true));
    assertTrue(m.trySet("2", "Hello", true));
    assertEquals("World", m.get("2"));
    // already updated by this statement, so it has no effect
    // but still returns true because it was changed by this transaction
    assertTrue(m.trySet("2", null, true));

    assertTrue(m.trySet("3", "World", true));
    // not seen within this statement
    assertEquals("Hello", m.get("1"));
    assertEquals("World", m.get("2"));
    assertNull(m.get("3"));

    // start of statement
    startUpdate = tx.setSavepoint();
    m.setSavepoint(startUpdate);
    // select * from test
    assertNull(m.get("1"));
    assertEquals("Hello", m.get("2"));
    assertEquals("World", m.get("3"));

    // start of statement
    startUpdate = tx.setSavepoint();
    m.setSavepoint(startUpdate);
    // update test set id = 1
    // should fail: duplicate key
    assertTrue(m.trySet("2", null, true));
    assertTrue(m.trySet("1", "Hello", true));
    assertTrue(m.trySet("3", null, true));
    assertFalse(m.trySet("1", "World", true));
    tx.rollbackToSavepoint(startUpdate);

    startUpdate = tx.setSavepoint();
    m.setSavepoint(startUpdate);
    assertNull(m.get("1"));
    assertEquals("Hello", m.get("2"));
    assertEquals("World", m.get("3"));

    tx.commit();

    ts.close();
    s.close();
  }
  private void testGetModifiedMaps() {
    MVStore s = MVStore.open(null);
    TransactionStore ts = new TransactionStore(s);
    Transaction tx;
    TransactionMap<String, String> m1, m2, m3;
    long sp;

    tx = ts.begin();
    m1 = tx.openMap("m1");
    m2 = tx.openMap("m2");
    m3 = tx.openMap("m3");
    assertFalse(tx.getChanges(0).hasNext());
    tx.commit();

    tx = ts.begin();
    m1 = tx.openMap("m1");
    m2 = tx.openMap("m2");
    m3 = tx.openMap("m3");
    m1.put("1", "100");
    sp = tx.setSavepoint();
    m2.put("1", "100");
    m3.put("1", "100");
    Iterator<Change> it = tx.getChanges(sp);
    assertTrue(it.hasNext());
    Change c;
    c = it.next();
    assertEquals("m3", c.mapName);
    assertEquals("1", c.key.toString());
    assertNull(c.value);
    assertTrue(it.hasNext());
    c = it.next();
    assertEquals("m2", c.mapName);
    assertEquals("1", c.key.toString());
    assertNull(c.value);
    assertFalse(it.hasNext());

    it = tx.getChanges(0);
    assertTrue(it.hasNext());
    c = it.next();
    assertEquals("m3", c.mapName);
    assertEquals("1", c.key.toString());
    assertNull(c.value);
    assertTrue(it.hasNext());
    c = it.next();
    assertEquals("m2", c.mapName);
    assertEquals("1", c.key.toString());
    assertNull(c.value);
    assertTrue(it.hasNext());
    c = it.next();
    assertEquals("m1", c.mapName);
    assertEquals("1", c.key.toString());
    assertNull(c.value);
    assertFalse(it.hasNext());

    tx.rollbackToSavepoint(sp);

    it = tx.getChanges(0);
    assertTrue(it.hasNext());
    c = it.next();
    assertEquals("m1", c.mapName);
    assertEquals("1", c.key.toString());
    assertNull(c.value);
    assertFalse(it.hasNext());

    tx.commit();

    s.close();
  }