Merge branch '545-denormalise-statuses' into 'maintenance-0.16'

Backport: Add denormalised columns to statuses table

See merge request akwizgran/briar!730

bramble-core/src/main/java/org/briarproject/bramble/db/Database.java

@@ -97,9 +97,12 @@ interface Database<T> {
 
 	/**
 	 * Stores a message.
+	 *
+	 * @param sender the contact from whom the message was received, or null
+	 * if the message was created locally.
 	 */
-	void addMessage(T txn, Message m, State state, boolean shared)
-			throws DbException;
+	void addMessage(T txn, Message m, State state, boolean shared,
+			@Nullable ContactId sender) throws DbException;
 
 	/**
 	 * Adds a dependency between two messages in the given group.
@@ -112,16 +115,6 @@ interface Database<T> {
 	 */
 	void addOfferedMessage(T txn, ContactId c, MessageId m) throws DbException;
 
-	/**
-	 * Initialises the status of the given message with respect to the given
-	 * contact.
-	 *
-	 * @param ack whether the message needs to be acknowledged.
-	 * @param seen whether the contact has seen the message.
-	 */
-	void addStatus(T txn, ContactId c, MessageId m, boolean ack, boolean seen)
-			throws DbException;
-
 	/**
 	 * Stores a transport.
 	 */
@@ -280,7 +273,7 @@ interface Database<T> {
 	 * <p/>
 	 * Read-only.
 	 */
-	Collection<ContactId> getGroupVisibility(T txn, GroupId g)
+	Map<ContactId, Boolean> getGroupVisibility(T txn, GroupId g)
 			throws DbException;
 
 	/**
@@ -584,13 +577,6 @@ interface Database<T> {
 	 */
 	void removeMessage(T txn, MessageId m) throws DbException;
 
-	/**
-	 * Removes an offered message that was offered by the given contact, or
-	 * returns false if there is no such message.
-	 */
-	boolean removeOfferedMessage(T txn, ContactId c, MessageId m)
-			throws DbException;
-
 	/**
 	 * Removes the given offered messages that were offered by the given
 	 * contact.
@@ -598,12 +584,6 @@ interface Database<T> {
 	void removeOfferedMessages(T txn, ContactId c,
 			Collection<MessageId> requested) throws DbException;
 
-	/**
-	 * Removes the status of the given message with respect to the given
-	 * contact.
-	 */
-	void removeStatus(T txn, ContactId c, MessageId m) throws DbException;
-
 	/**
 	 * Removes a transport (and all associated state) from the database.
 	 */

bramble-core/src/main/java/org/briarproject/bramble/db/DatabaseComponentImpl.java

@@ -215,7 +215,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		if (!db.containsGroup(txn, m.getGroupId()))
 			throw new NoSuchGroupException();
 		if (!db.containsMessage(txn, m.getId())) {
-			addMessage(txn, m, DELIVERED, shared, null);
+			db.addMessage(txn, m, DELIVERED, shared, null);
 			transaction.attach(new MessageAddedEvent(m, null));
 			transaction.attach(new MessageStateChangedEvent(m.getId(), true,
 					DELIVERED));
@@ -224,16 +224,6 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		db.mergeMessageMetadata(txn, m.getId(), meta);
 	}
 
-	private void addMessage(T txn, Message m, State state, boolean shared,
-			@Nullable ContactId sender) throws DbException {
-		db.addMessage(txn, m, state, shared);
-		for (ContactId c : db.getGroupVisibility(txn, m.getGroupId())) {
-			boolean offered = db.removeOfferedMessage(txn, c, m.getId());
-			boolean seen = offered || (sender != null && c.equals(sender));
-			db.addStatus(txn, c, m.getId(), seen, seen);
-		}
-	}
-
 	@Override
 	public void addTransport(Transaction transaction, TransportId t,
 			int maxLatency) throws DbException {
@@ -682,7 +672,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 				db.raiseSeenFlag(txn, c, m.getId());
 				db.raiseAckFlag(txn, c, m.getId());
 			} else {
-				addMessage(txn, m, UNKNOWN, false, c);
+				db.addMessage(txn, m, UNKNOWN, false, c);
 				transaction.attach(new MessageAddedEvent(m, c));
 			}
 			transaction.attach(new MessageToAckEvent(c));
@@ -750,7 +740,8 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		GroupId id = g.getId();
 		if (!db.containsGroup(txn, id))
 			throw new NoSuchGroupException();
-		Collection<ContactId> affected = db.getGroupVisibility(txn, id);
+		Collection<ContactId> affected =
+				db.getGroupVisibility(txn, id).keySet();
 		db.removeGroup(txn, id);
 		transaction.attach(new GroupRemovedEvent(g));
 		transaction.attach(new GroupVisibilityUpdatedEvent(affected));
@@ -820,19 +811,9 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			throw new NoSuchGroupException();
 		Visibility old = db.getGroupVisibility(txn, c, g);
 		if (old == v) return;
-		if (old == INVISIBLE) {
-			db.addGroupVisibility(txn, c, g, v == SHARED);
-			for (MessageId m : db.getMessageIds(txn, g)) {
-				boolean seen = db.removeOfferedMessage(txn, c, m);
-				db.addStatus(txn, c, m, seen, seen);
-			}
-		} else if (v == INVISIBLE) {
-			db.removeGroupVisibility(txn, c, g);
-			for (MessageId m : db.getMessageIds(txn, g))
-				db.removeStatus(txn, c, m);
-		} else {
-			db.setGroupVisibility(txn, c, g, v == SHARED);
-		}
+		if (old == INVISIBLE) db.addGroupVisibility(txn, c, g, v == SHARED);
+		else if (v == INVISIBLE) db.removeGroupVisibility(txn, c, g);
+		else db.setGroupVisibility(txn, c, g, v == SHARED);
 		List<ContactId> affected = Collections.singletonList(c);
 		transaction.attach(new GroupVisibilityUpdatedEvent(affected));
 	}

bramble-core/src/main/java/org/briarproject/bramble/db/JdbcDatabase.java

@@ -34,6 +34,7 @@ import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.sql.Statement;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
@@ -72,7 +73,7 @@ import static org.briarproject.bramble.db.ExponentialBackoff.calculateExpiry;
 abstract class JdbcDatabase implements Database<Connection> {
 
 	// Package access for testing
-	static final int CODE_SCHEMA_VERSION = 31;
+	static final int CODE_SCHEMA_VERSION = 32;
 
 	private static final String CREATE_SETTINGS =
 			"CREATE TABLE settings"
@@ -188,6 +189,13 @@ abstract class JdbcDatabase implements Database<Connection> {
 			"CREATE TABLE statuses"
 					+ " (messageId HASH NOT NULL,"
 					+ " contactId INT NOT NULL,"
+					+ " groupId HASH NOT NULL," // Denormalised
+					+ " timestamp BIGINT NOT NULL," // Denormalised
+					+ " length INT NOT NULL," // Denormalised
+					+ " state INT NOT NULL," // Denormalised
+					+ " groupShared BOOLEAN NOT NULL," // Denormalised
+					+ " messageShared BOOLEAN NOT NULL," // Denormalised
+					+ " deleted BOOLEAN NOT NULL," // Denormalised
 					+ " ack BOOLEAN NOT NULL,"
 					+ " seen BOOLEAN NOT NULL,"
 					+ " requested BOOLEAN NOT NULL,"
@@ -199,6 +207,9 @@ abstract class JdbcDatabase implements Database<Connection> {
 					+ " ON DELETE CASCADE,"
 					+ " FOREIGN KEY (contactId)"
 					+ " REFERENCES contacts (contactId)"
+					+ " ON DELETE CASCADE,"
+					+ " FOREIGN KEY (groupId)"
+					+ " REFERENCES groups (groupId)"
 					+ " ON DELETE CASCADE)";
 
 	private static final String CREATE_TRANSPORTS =
@@ -252,6 +263,14 @@ abstract class JdbcDatabase implements Database<Connection> {
 			"CREATE INDEX IF NOT EXISTS messageMetadataByGroupIdState"
 					+ " ON messageMetadata (groupId, state)";
 
+	private static final String INDEX_STATUSES_BY_CONTACT_ID_GROUP_ID =
+			"CREATE INDEX IF NOT EXISTS statusesByContactIdGroupId"
+					+ " ON statuses (contactId, groupId)";
+
+	private static final String INDEX_STATUSES_BY_CONTACT_ID_TIMESTAMP =
+			"CREATE INDEX IF NOT EXISTS statusesByContactIdTimestamp"
+					+ " ON statuses (contactId, timestamp)";
+
 	private static final Logger LOG =
 			Logger.getLogger(JdbcDatabase.class.getName());
 
@@ -343,7 +362,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 
 	// Package access for testing
 	List<Migration<Connection>> getMigrations() {
-		return Collections.singletonList(new Migration30_31());
+		return Arrays.asList(new Migration30_31(), new Migration31_32());
 	}
 
 	private void storeSchemaVersion(Connection txn, int version)
@@ -401,6 +420,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 			s.executeUpdate(INDEX_CONTACTS_BY_AUTHOR_ID);
 			s.executeUpdate(INDEX_GROUPS_BY_CLIENT_ID);
 			s.executeUpdate(INDEX_MESSAGE_METADATA_BY_GROUP_ID_STATE);
+			s.executeUpdate(INDEX_STATUSES_BY_CONTACT_ID_GROUP_ID);
+			s.executeUpdate(INDEX_STATUSES_BY_CONTACT_ID_TIMESTAMP);
 			s.close();
 		} catch (SQLException e) {
 			tryToClose(s);
@@ -578,7 +599,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 
 	@Override
 	public void addGroupVisibility(Connection txn, ContactId c, GroupId g,
-			boolean shared) throws DbException {
+			boolean groupShared) throws DbException {
 		PreparedStatement ps = null;
 		try {
 			String sql = "INSERT INTO groupVisibilities"
@@ -587,16 +608,50 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps = txn.prepareStatement(sql);
 			ps.setInt(1, c.getInt());
 			ps.setBytes(2, g.getBytes());
-			ps.setBoolean(3, shared);
+			ps.setBoolean(3, groupShared);
 			int affected = ps.executeUpdate();
 			if (affected != 1) throw new DbStateException();
 			ps.close();
+			// Create a status row for each message in the group
+			addStatus(txn, c, g, groupShared);
 		} catch (SQLException e) {
 			tryToClose(ps);
 			throw new DbException(e);
 		}
 	}
 
+	private void addStatus(Connection txn, ContactId c, GroupId g,
+			boolean groupShared) throws DbException {
+		PreparedStatement ps = null;
+		ResultSet rs = null;
+		try {
+			String sql = "SELECT messageId, timestamp, state, shared,"
+					+ " length, raw IS NULL"
+					+ " FROM messages"
+					+ " WHERE groupId = ?";
+			ps = txn.prepareStatement(sql);
+			ps.setBytes(1, g.getBytes());
+			rs = ps.executeQuery();
+			while (rs.next()) {
+				MessageId id = new MessageId(rs.getBytes(1));
+				long timestamp = rs.getLong(2);
+				State state = State.fromValue(rs.getInt(3));
+				boolean messageShared = rs.getBoolean(4);
+				int length = rs.getInt(5);
+				boolean deleted = rs.getBoolean(6);
+				boolean seen = removeOfferedMessage(txn, c, id);
+				addStatus(txn, id, c, g, timestamp, length, state, groupShared,
+						messageShared, deleted, seen);
+			}
+			rs.close();
+			ps.close();
+		} catch (SQLException e) {
+			tryToClose(rs);
+			tryToClose(ps);
+			throw new DbException(e);
+		}
+	}
+
 	@Override
 	public void addLocalAuthor(Connection txn, LocalAuthor a)
 			throws DbException {
@@ -622,7 +677,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 
 	@Override
 	public void addMessage(Connection txn, Message m, State state,
-			boolean shared) throws DbException {
+			boolean messageShared, @Nullable ContactId sender)
+			throws DbException {
 		PreparedStatement ps = null;
 		try {
 			String sql = "INSERT INTO messages (messageId, groupId, timestamp,"
@@ -633,13 +689,24 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps.setBytes(2, m.getGroupId().getBytes());
 			ps.setLong(3, m.getTimestamp());
 			ps.setInt(4, state.getValue());
-			ps.setBoolean(5, shared);
+			ps.setBoolean(5, messageShared);
 			byte[] raw = m.getRaw();
 			ps.setInt(6, raw.length);
 			ps.setBytes(7, raw);
 			int affected = ps.executeUpdate();
 			if (affected != 1) throw new DbStateException();
 			ps.close();
+			// Create a status row for each contact that can see the group
+			Map<ContactId, Boolean> visibility =
+					getGroupVisibility(txn, m.getGroupId());
+			for (Entry<ContactId, Boolean> e : visibility.entrySet()) {
+				ContactId c = e.getKey();
+				boolean offered = removeOfferedMessage(txn, c, m.getId());
+				boolean seen = offered || (sender != null && c.equals(sender));
+				addStatus(txn, m.getId(), c, m.getGroupId(), m.getTimestamp(),
+						m.getLength(), state, e.getValue(), messageShared,
+						false, seen);
+			}
 		} catch (SQLException e) {
 			tryToClose(ps);
 			throw new DbException(e);
@@ -677,19 +744,28 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}
 
-	@Override
-	public void addStatus(Connection txn, ContactId c, MessageId m, boolean ack,
-			boolean seen) throws DbException {
+	private void addStatus(Connection txn, MessageId m, ContactId c, GroupId g,
+			long timestamp, int length, State state, boolean groupShared,
+			boolean messageShared, boolean deleted, boolean seen)
+			throws DbException {
 		PreparedStatement ps = null;
 		try {
-			String sql = "INSERT INTO statuses (messageId, contactId, ack,"
-					+ " seen, requested, expiry, txCount)"
-					+ " VALUES (?, ?, ?, ?, FALSE, 0, 0)";
+			String sql = "INSERT INTO statuses (messageId, contactId, groupId,"
+					+ " timestamp, length, state, groupShared, messageShared,"
+					+ " deleted, ack, seen, requested, expiry, txCount)"
+					+ " VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, FALSE, 0, 0)";
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, m.getBytes());
 			ps.setInt(2, c.getInt());
-			ps.setBoolean(3, ack);
-			ps.setBoolean(4, seen);
+			ps.setBytes(3, g.getBytes());
+			ps.setLong(4, timestamp);
+			ps.setInt(5, length);
+			ps.setInt(6, state.getValue());
+			ps.setBoolean(7, groupShared);
+			ps.setBoolean(8, messageShared);
+			ps.setBoolean(9, deleted);
+			ps.setBoolean(10, seen);
+			ps.setBoolean(11, seen);
 			int affected = ps.executeUpdate();
 			if (affected != 1) throw new DbStateException();
 			ps.close();
@@ -941,12 +1017,9 @@ abstract class JdbcDatabase implements Database<Connection> {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
-			String sql = "SELECT NULL FROM messages AS m"
-					+ " JOIN groupVisibilities AS gv"
-					+ " ON m.groupId = gv.groupId"
-					+ " WHERE messageId = ?"
-					+ " AND contactId = ?"
-					+ " AND m.shared = TRUE";
+			String sql = "SELECT NULL FROM statuses"
+					+ " WHERE messageId = ? AND contactId = ?"
+					+ " AND messageShared = TRUE";
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, m.getBytes());
 			ps.setInt(2, c.getInt());
@@ -998,6 +1071,13 @@ abstract class JdbcDatabase implements Database<Connection> {
 			if (affected < 0) throw new DbStateException();
 			if (affected > 1) throw new DbStateException();
 			ps.close();
+			// Update denormalised column in statuses
+			sql = "UPDATE statuses SET deleted = TRUE WHERE messageId = ?";
+			ps = txn.prepareStatement(sql);
+			ps.setBytes(1, m.getBytes());
+			affected = ps.executeUpdate();
+			if (affected < 0) throw new DbStateException();
+			ps.close();
 		} catch (SQLException e) {
 			tryToClose(ps);
 			throw new DbException(e);
@@ -1220,18 +1300,19 @@ abstract class JdbcDatabase implements Database<Connection> {
 	}
 
 	@Override
-	public Collection<ContactId> getGroupVisibility(Connection txn, GroupId g)
+	public Map<ContactId, Boolean> getGroupVisibility(Connection txn, GroupId g)
 			throws DbException {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
-			String sql = "SELECT contactId FROM groupVisibilities"
+			String sql = "SELECT contactId, shared FROM groupVisibilities"
 					+ " WHERE groupId = ?";
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, g.getBytes());
 			rs = ps.executeQuery();
-			List<ContactId> visible = new ArrayList<>();
-			while (rs.next()) visible.add(new ContactId(rs.getInt(1)));
+			Map<ContactId, Boolean> visible = new HashMap<>();
+			while (rs.next())
+				visible.put(new ContactId(rs.getInt(1)), rs.getBoolean(2));
 			rs.close();
 			ps.close();
 			return visible;
@@ -1509,12 +1590,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
-			String sql = "SELECT m.messageId, txCount > 0, seen"
-					+ " FROM messages AS m"
-					+ " JOIN statuses AS s"
-					+ " ON m.messageId = s.messageId"
-					+ " WHERE groupId = ?"
-					+ " AND contactId = ?";
+			String sql = "SELECT messageId, txCount > 0, seen FROM statuses"
+					+ " WHERE groupId = ? AND contactId = ?";
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, g.getBytes());
 			ps.setInt(2, c.getInt());
@@ -1537,15 +1614,13 @@ abstract class JdbcDatabase implements Database<Connection> {
 	}
 
 	@Override
-	public MessageStatus getMessageStatus(Connection txn,
-			ContactId c, MessageId m) throws DbException {
+	public MessageStatus getMessageStatus(Connection txn, ContactId c,
+			MessageId m) throws DbException {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
-			String sql = "SELECT txCount > 0, seen"
-					+ " FROM statuses"
-					+ " WHERE messageId = ?"
-					+ " AND contactId = ?";
+			String sql = "SELECT txCount > 0, seen FROM statuses"
+					+ " WHERE messageId = ? AND contactId = ?";
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, m.getBytes());
 			ps.setInt(2, c.getInt());
@@ -1687,14 +1762,10 @@ abstract class JdbcDatabase implements Database<Connection> {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
-			String sql = "SELECT m.messageId FROM messages AS m"
-					+ " JOIN groupVisibilities AS gv"
-					+ " ON m.groupId = gv.groupId"
-					+ " JOIN statuses AS s"
-					+ " ON m.messageId = s.messageId"
-					+ " AND gv.contactId = s.contactId"
-					+ " WHERE gv.contactId = ? AND gv.shared = TRUE"
-					+ " AND state = ? AND m.shared = TRUE AND raw IS NOT NULL"
+			String sql = "SELECT messageId FROM statuses"
+					+ " WHERE contactId = ? AND state = ?"
+					+ " AND groupShared = TRUE AND messageShared = TRUE"
+					+ " AND deleted = FALSE"
 					+ " AND seen = FALSE AND requested = FALSE"
 					+ " AND expiry < ?"
 					+ " ORDER BY timestamp LIMIT ?";
@@ -1748,14 +1819,10 @@ abstract class JdbcDatabase implements Database<Connection> {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
-			String sql = "SELECT length, m.messageId FROM messages AS m"
-					+ " JOIN groupVisibilities AS gv"
-					+ " ON m.groupId = gv.groupId"
-					+ " JOIN statuses AS s"
-					+ " ON m.messageId = s.messageId"
-					+ " AND gv.contactId = s.contactId"
-					+ " WHERE gv.contactId = ? AND gv.shared = TRUE"
-					+ " AND state = ? AND m.shared = TRUE AND raw IS NOT NULL"
+			String sql = "SELECT length, messageId FROM statuses"
+					+ " WHERE contactId = ? AND state = ?"
+					+ " AND groupShared = TRUE AND messageShared = TRUE"
+					+ " AND deleted = FALSE"
 					+ " AND seen = FALSE"
 					+ " AND expiry < ?"
 					+ " ORDER BY timestamp";
@@ -1819,8 +1886,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 	}
 
 	@Override
-	public Collection<MessageId> getMessagesToShare(
-			Connection txn, ClientId c) throws DbException {
+	public Collection<MessageId> getMessagesToShare(Connection txn, ClientId c)
+			throws DbException {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
@@ -1854,15 +1921,10 @@ abstract class JdbcDatabase implements Database<Connection> {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
-			String sql = "SELECT expiry FROM messages AS m"
-					+ " JOIN groupVisibilities AS gv"
-					+ " ON m.groupId = gv.groupId"
-					+ " JOIN statuses AS s"
-					+ " ON m.messageId = s.messageId"
-					+ " AND gv.contactId = s.contactId"
-					+ " WHERE gv.contactId = ? AND gv.shared = TRUE"
-					+ " AND state = ? AND m.shared = TRUE AND raw IS NOT NULL"
-					+ " AND seen = FALSE"
+			String sql = "SELECT expiry FROM statuses"
+					+ " WHERE contactId = ? AND state = ?"
+					+ " AND groupShared = TRUE AND messageShared = TRUE"
+					+ " AND deleted = FALSE AND seen = FALSE"
 					+ " ORDER BY expiry LIMIT 1";
 			ps = txn.prepareStatement(sql);
 			ps.setInt(1, c.getInt());
@@ -1914,14 +1976,10 @@ abstract class JdbcDatabase implements Database<Connection> {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
-			String sql = "SELECT length, m.messageId FROM messages AS m"
-					+ " JOIN groupVisibilities AS gv"
-					+ " ON m.groupId = gv.groupId"
-					+ " JOIN statuses AS s"
-					+ " ON m.messageId = s.messageId"
-					+ " AND gv.contactId = s.contactId"
-					+ " WHERE gv.contactId = ? AND gv.shared = TRUE"
-					+ " AND state = ? AND m.shared = TRUE AND raw IS NOT NULL"
+			String sql = "SELECT length, messageId FROM statuses"
+					+ " WHERE contactId = ? AND state = ?"
+					+ " AND groupShared = TRUE AND messageShared = TRUE"
+					+ " AND deleted = FALSE"
 					+ " AND seen = FALSE AND requested = TRUE"
 					+ " AND expiry < ?"
 					+ " ORDER BY timestamp";
@@ -2397,6 +2455,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 			int affected = ps.executeUpdate();
 			if (affected != 1) throw new DbStateException();
 			ps.close();
+			// Remove status rows for the messages in the group
+			for (MessageId m : getMessageIds(txn, g)) removeStatus(txn, c, m);
 		} catch (SQLException e) {
 			tryToClose(ps);
 			throw new DbException(e);
@@ -2436,8 +2496,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}
 
-	@Override
-	public boolean removeOfferedMessage(Connection txn, ContactId c,
+	private boolean removeOfferedMessage(Connection txn, ContactId c,
 			MessageId m) throws DbException {
 		PreparedStatement ps = null;
 		try {
@@ -2481,16 +2540,15 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}
 
-	@Override
-	public void removeStatus(Connection txn, ContactId c, MessageId m)
+	private void removeStatus(Connection txn, ContactId c, MessageId m)
 			throws DbException {
 		PreparedStatement ps = null;
 		try {
 			String sql = "DELETE FROM statuses"
-					+ " WHERE contactId = ? AND messageId = ?";
+					+ " WHERE messageId = ? AND contactId = ?";
 			ps = txn.prepareStatement(sql);
-			ps.setInt(1, c.getInt());
-			ps.setBytes(2, m.getBytes());
+			ps.setBytes(1, m.getBytes());
+			ps.setInt(2, c.getInt());
 			int affected = ps.executeUpdate();
 			if (affected != 1) throw new DbStateException();
 			ps.close();
@@ -2586,6 +2644,16 @@ abstract class JdbcDatabase implements Database<Connection> {
 			int affected = ps.executeUpdate();
 			if (affected < 0 || affected > 1) throw new DbStateException();
 			ps.close();
+			// Update denormalised column in statuses
+			sql = "UPDATE statuses SET groupShared = ?"
+					+ " WHERE contactId = ? AND groupId = ?";
+			ps = txn.prepareStatement(sql);
+			ps.setBoolean(1, shared);
+			ps.setInt(2, c.getInt());
+			ps.setBytes(3, g.getBytes());
+			affected = ps.executeUpdate();
+			if (affected < 0) throw new DbStateException();
+			ps.close();
 		} catch (SQLException e) {
 			tryToClose(ps);
 			throw new DbException(e);
@@ -2604,6 +2672,14 @@ abstract class JdbcDatabase implements Database<Connection> {
 			int affected = ps.executeUpdate();
 			if (affected < 0 || affected > 1) throw new DbStateException();
 			ps.close();
+			// Update denormalised column in statuses
+			sql = "UPDATE statuses SET messageShared = TRUE"
+					+ " WHERE messageId = ?";
+			ps = txn.prepareStatement(sql);
+			ps.setBytes(1, m.getBytes());
+			affected = ps.executeUpdate();
+			if (affected < 0) throw new DbStateException();
+			ps.close();
 		} catch (SQLException e) {
 			tryToClose(ps);
 			throw new DbException(e);
@@ -2630,6 +2706,14 @@ abstract class JdbcDatabase implements Database<Connection> {
 			affected = ps.executeUpdate();
 			if (affected < 0) throw new DbStateException();
 			ps.close();
+			// Update denormalised column in statuses
+			sql = "UPDATE statuses SET state = ? WHERE messageId = ?";
+			ps = txn.prepareStatement(sql);
+			ps.setInt(1, state.getValue());
+			ps.setBytes(2, m.getBytes());
+			affected = ps.executeUpdate();
+			if (affected < 0) throw new DbStateException();
+			ps.close();
 		} catch (SQLException e) {
 			tryToClose(ps);
 			throw new DbException(e);

bramble-core/src/main/java/org/briarproject/bramble/db/Migration31_32.java

@@ -0,0 +1,84 @@
+package org.briarproject.bramble.db;
+
+import org.briarproject.bramble.api.db.DbException;
+
+import java.sql.Connection;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.util.logging.Logger;
+
+import javax.annotation.Nullable;
+
+import static java.util.logging.Level.WARNING;
+
+class Migration31_32 implements Migration<Connection> {
+
+	private static final Logger LOG =
+			Logger.getLogger(Migration31_32.class.getName());
+
+	@Override
+	public int getStartVersion() {
+		return 31;
+	}
+
+	@Override
+	public int getEndVersion() {
+		return 32;
+	}
+
+	@Override
+	public void migrate(Connection txn) throws DbException {
+		Statement s = null;
+		try {
+			s = txn.createStatement();
+			// Add denormalised columns
+			s.execute("ALTER TABLE statuses ADD COLUMN"
+					+ " (groupId BINARY(32),"
+					+ " timestamp BIGINT,"
+					+ " length INT,"
+					+ " state INT,"
+					+ " groupShared BOOLEAN,"
+					+ " messageShared BOOLEAN,"
+					+ " deleted BOOLEAN)");
+			// Populate columns from messages table
+			s.execute("UPDATE statuses AS s SET (groupId, timestamp, length,"
+					+ " state, messageShared, deleted) ="
+					+ " (SELECT groupId, timestamp, length, state, shared,"
+					+ " raw IS NULL FROM messages AS m"
+					+ " WHERE s.messageId = m.messageId)");
+			// Populate column from groupVisibilities table
+			s.execute("UPDATE statuses AS s SET groupShared ="
+					+ " (SELECT shared FROM groupVisibilities AS gv"
+					+ " WHERE s.contactId = gv.contactId"
+					+ " AND s.groupId = gv.groupId)");
+			// Add not null constraints now columns have been populated
+			s.execute("ALTER TABLE statuses ALTER COLUMN groupId SET NOT NULL");
+			s.execute("ALTER TABLE statuses ALTER COLUMN timestamp"
+					+ " SET NOT NULL");
+			s.execute("ALTER TABLE statuses ALTER COLUMN length SET NOT NULL");
+			s.execute("ALTER TABLE statuses ALTER COLUMN state SET NOT NULL");
+			s.execute("ALTER TABLE statuses ALTER COLUMN groupShared"
+					+ " SET NOT NULL");
+			s.execute("ALTER TABLE statuses ALTER COLUMN messageShared"
+					+ " SET NOT NULL");
+			s.execute("ALTER TABLE statuses ALTER COLUMN deleted SET NOT NULL");
+			// Add foreign key constraint
+			s.execute("ALTER TABLE statuses"
+					+ " ADD CONSTRAINT statusesForeignKeyGroupId"
+					+ " FOREIGN KEY (groupId)"
+					+ " REFERENCES groups (groupId)"
+					+ " ON DELETE CASCADE");
+		} catch (SQLException e) {
+			tryToClose(s);
+			throw new DbException(e);
+		}
+	}
+
+	private void tryToClose(@Nullable Statement s) {
+		try {
+			if (s != null) s.close();
+		} catch (SQLException e) {
+			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+		}
+	}
+}

bramble-core/src/test/java/org/briarproject/bramble/db/DatabaseComponentImplTest.java

@@ -48,6 +48,7 @@ import org.briarproject.bramble.api.transport.IncomingKeys;
 import org.briarproject.bramble.api.transport.OutgoingKeys;
 import org.briarproject.bramble.api.transport.TransportKeys;
 import org.briarproject.bramble.test.BrambleMockTestCase;
+import org.briarproject.bramble.test.CaptureArgumentAction;
 import org.briarproject.bramble.test.TestUtils;
 import org.briarproject.bramble.util.StringUtils;
 import org.jmock.Expectations;
@@ -56,9 +57,12 @@ import org.junit.Test;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
-import java.util.Collections;
 import java.util.Map;
+import java.util.concurrent.atomic.AtomicReference;
 
+import static java.util.Collections.emptyMap;
+import static java.util.Collections.singletonList;
+import static java.util.Collections.singletonMap;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_PUBLIC_KEY_LENGTH;
 import static org.briarproject.bramble.api.sync.Group.Visibility.INVISIBLE;
 import static org.briarproject.bramble.api.sync.Group.Visibility.SHARED;
@@ -160,7 +164,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 					ContactStatusChangedEvent.class)));
 			// getContacts()
 			oneOf(database).getContacts(txn);
-			will(returnValue(Collections.singletonList(contact)));
+			will(returnValue(singletonList(contact)));
 			// addGroup()
 			oneOf(database).containsGroup(txn, groupId);
 			will(returnValue(false));
@@ -171,12 +175,12 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			will(returnValue(true));
 			// getGroups()
 			oneOf(database).getGroups(txn, clientId);
-			will(returnValue(Collections.singletonList(group)));
+			will(returnValue(singletonList(group)));
 			// removeGroup()
 			oneOf(database).containsGroup(txn, groupId);
 			will(returnValue(true));
 			oneOf(database).getGroupVisibility(txn, groupId);
-			will(returnValue(Collections.emptyList()));
+			will(returnValue(emptyMap()));
 			oneOf(database).removeGroup(txn, groupId);
 			oneOf(eventBus).broadcast(with(any(GroupRemovedEvent.class)));
 			oneOf(eventBus).broadcast(with(any(
@@ -206,11 +210,11 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			assertEquals(contactId,
 					db.addContact(transaction, author, localAuthorId, true,
 							true));
-			assertEquals(Collections.singletonList(contact),
+			assertEquals(singletonList(contact),
 					db.getContacts(transaction));
 			db.addGroup(transaction, group); // First time - listeners called
 			db.addGroup(transaction, group); // Second time - not called
-			assertEquals(Collections.singletonList(group),
+			assertEquals(singletonList(group),
 					db.getGroups(transaction, clientId));
 			db.removeGroup(transaction, group);
 			db.removeContact(transaction, contactId);
@@ -255,13 +259,8 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			will(returnValue(true));
 			oneOf(database).containsMessage(txn, messageId);
 			will(returnValue(false));
-			oneOf(database).addMessage(txn, message, DELIVERED, true);
+			oneOf(database).addMessage(txn, message, DELIVERED, true, null);
 			oneOf(database).mergeMessageMetadata(txn, messageId, metadata);
-			oneOf(database).getGroupVisibility(txn, groupId);
-			will(returnValue(Collections.singletonList(contactId)));
-			oneOf(database).removeOfferedMessage(txn, contactId, messageId);
-			will(returnValue(false));
-			oneOf(database).addStatus(txn, contactId, messageId, false, false);
 			oneOf(database).commitTransaction(txn);
 			// The message was added, so the listeners should be called
 			oneOf(eventBus).broadcast(with(any(MessageAddedEvent.class)));
@@ -397,7 +396,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 
 		transaction = db.startTransaction(false);
 		try {
-			Ack a = new Ack(Collections.singletonList(messageId));
+			Ack a = new Ack(singletonList(messageId));
 			db.receiveAck(transaction, contactId, a);
 			fail();
 		} catch (NoSuchContactException expected) {
@@ -418,7 +417,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 
 		transaction = db.startTransaction(false);
 		try {
-			Offer o = new Offer(Collections.singletonList(messageId));
+			Offer o = new Offer(singletonList(messageId));
 			db.receiveOffer(transaction, contactId, o);
 			fail();
 		} catch (NoSuchContactException expected) {
@@ -429,7 +428,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 
 		transaction = db.startTransaction(false);
 		try {
-			Request r = new Request(Collections.singletonList(messageId));
+			Request r = new Request(singletonList(messageId));
 			db.receiveRequest(transaction, contactId, r);
 			fail();
 		} catch (NoSuchContactException expected) {
@@ -1022,7 +1021,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 
 		Transaction transaction = db.startTransaction(false);
 		try {
-			Ack a = new Ack(Collections.singletonList(messageId));
+			Ack a = new Ack(singletonList(messageId));
 			db.receiveAck(transaction, contactId, a);
 			db.commitTransaction(transaction);
 		} finally {
@@ -1042,12 +1041,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			will(returnValue(VISIBLE));
 			oneOf(database).containsMessage(txn, messageId);
 			will(returnValue(false));
-			oneOf(database).addMessage(txn, message, UNKNOWN, false);
-			oneOf(database).getGroupVisibility(txn, groupId);
-			will(returnValue(Collections.singletonList(contactId)));
-			oneOf(database).removeOfferedMessage(txn, contactId, messageId);
-			will(returnValue(false));
-			oneOf(database).addStatus(txn, contactId, messageId, true, true);
+			oneOf(database).addMessage(txn, message, UNKNOWN, false, contactId);
 			// Second time
 			oneOf(database).containsContact(txn, contactId);
 			will(returnValue(true));
@@ -1197,7 +1191,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 
 		Transaction transaction = db.startTransaction(false);
 		try {
-			Request r = new Request(Collections.singletonList(messageId));
+			Request r = new Request(singletonList(messageId));
 			db.receiveRequest(transaction, contactId, r);
 			db.commitTransaction(transaction);
 		} finally {
@@ -1206,7 +1200,11 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 	}
 
 	@Test
-	public void testChangingVisibilityCallsListeners() throws Exception {
+	public void testChangingVisibilityFromInvisibleToVisibleCallsListeners()
+			throws Exception {
+		AtomicReference<GroupVisibilityUpdatedEvent> event =
+				new AtomicReference<>();
+
 		context.checking(new Expectations() {{
 			oneOf(database).startTransaction();
 			will(returnValue(txn));
@@ -1215,16 +1213,13 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			oneOf(database).containsGroup(txn, groupId);
 			will(returnValue(true));
 			oneOf(database).getGroupVisibility(txn, contactId, groupId);
-			will(returnValue(INVISIBLE)); // Not yet visible
+			will(returnValue(INVISIBLE));
 			oneOf(database).addGroupVisibility(txn, contactId, groupId, false);
-			oneOf(database).getMessageIds(txn, groupId);
-			will(returnValue(Collections.singletonList(messageId)));
-			oneOf(database).removeOfferedMessage(txn, contactId, messageId);
-			will(returnValue(false));
-			oneOf(database).addStatus(txn, contactId, messageId, false, false);
 			oneOf(database).commitTransaction(txn);
 			oneOf(eventBus).broadcast(with(any(
 					GroupVisibilityUpdatedEvent.class)));
+			will(new CaptureArgumentAction<>(event,
+					GroupVisibilityUpdatedEvent.class, 0));
 		}});
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
 				shutdown);
@@ -1236,6 +1231,48 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 		} finally {
 			db.endTransaction(transaction);
 		}
+
+		GroupVisibilityUpdatedEvent e = event.get();
+		assertNotNull(e);
+		assertEquals(singletonList(contactId), e.getAffectedContacts());
+	}
+
+	@Test
+	public void testChangingVisibilityFromVisibleToInvisibleCallsListeners()
+			throws Exception {
+		AtomicReference<GroupVisibilityUpdatedEvent> event =
+				new AtomicReference<>();
+
+		context.checking(new Expectations() {{
+			oneOf(database).startTransaction();
+			will(returnValue(txn));
+			oneOf(database).containsContact(txn, contactId);
+			will(returnValue(true));
+			oneOf(database).containsGroup(txn, groupId);
+			will(returnValue(true));
+			oneOf(database).getGroupVisibility(txn, contactId, groupId);
+			will(returnValue(VISIBLE));
+			oneOf(database).removeGroupVisibility(txn, contactId, groupId);
+			oneOf(database).commitTransaction(txn);
+			oneOf(eventBus).broadcast(with(any(
+					GroupVisibilityUpdatedEvent.class)));
+			will(new CaptureArgumentAction<>(event,
+					GroupVisibilityUpdatedEvent.class, 0));
+		}});
+		DatabaseComponent db = createDatabaseComponent(database, eventBus,
+				shutdown);
+
+		Transaction transaction = db.startTransaction(false);
+		try {
+			db.setGroupVisibility(transaction, contactId, groupId, INVISIBLE);
+			db.commitTransaction(transaction);
+		} finally {
+			db.endTransaction(transaction);
+		}
+
+		GroupVisibilityUpdatedEvent e = event.get();
+		assertNotNull(e);
+		assertEquals(singletonList(contactId), e.getAffectedContacts());
 	}
 
 	@Test
@@ -1267,8 +1304,8 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 	@Test
 	public void testTransportKeys() throws Exception {
 		TransportKeys transportKeys = createTransportKeys();
-		Map<ContactId, TransportKeys> keys = Collections.singletonMap(
-				contactId, transportKeys);
+		Map<ContactId, TransportKeys> keys =
+				singletonMap(contactId, transportKeys);
 		context.checking(new Expectations() {{
 			// startTransaction()
 			oneOf(database).startTransaction();
@@ -1476,13 +1513,8 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			will(returnValue(true));
 			oneOf(database).containsMessage(txn, messageId);
 			will(returnValue(false));
-			oneOf(database).addMessage(txn, message, DELIVERED, true);
-			oneOf(database).getGroupVisibility(txn, groupId);
-			will(returnValue(Collections.singletonList(contactId)));
+			oneOf(database).addMessage(txn, message, DELIVERED, true, null);
 			oneOf(database).mergeMessageMetadata(txn, messageId, metadata);
-			oneOf(database).removeOfferedMessage(txn, contactId, messageId);
-			will(returnValue(false));
-			oneOf(database).addStatus(txn, contactId, messageId, false, false);
 			// addMessageDependencies()
 			oneOf(database).containsMessage(txn, messageId);
 			will(returnValue(true));

bramble-core/src/test/java/org/briarproject/bramble/db/H2DatabaseTest.java

@@ -122,7 +122,7 @@ public class H2DatabaseTest extends BrambleTestCase {
 		db.addGroup(txn, group);
 		assertTrue(db.containsGroup(txn, groupId));
 		assertFalse(db.containsMessage(txn, messageId));
-		db.addMessage(txn, message, DELIVERED, true);
+		db.addMessage(txn, message, DELIVERED, true, null);
 		assertTrue(db.containsMessage(txn, messageId));
 		db.commitTransaction(txn);
 		db.close();
@@ -160,7 +160,7 @@ public class H2DatabaseTest extends BrambleTestCase {
 
 		// Add a group and a message
 		db.addGroup(txn, group);
-		db.addMessage(txn, message, DELIVERED, true);
+		db.addMessage(txn, message, DELIVERED, true, null);
 
 		// Removing the group should remove the message
 		assertTrue(db.containsMessage(txn, messageId));
@@ -182,18 +182,11 @@ public class H2DatabaseTest extends BrambleTestCase {
 				true, true));
 		db.addGroup(txn, group);
 		db.addGroupVisibility(txn, contactId, groupId, true);
-		db.addMessage(txn, message, DELIVERED, true);
+		db.addMessage(txn, message, DELIVERED, true, null);
 
-		// The message has no status yet, so it should not be sendable
-		Collection<MessageId> ids = db.getMessagesToSend(txn, contactId,
-				ONE_MEGABYTE);
-		assertTrue(ids.isEmpty());
-		ids = db.getMessagesToOffer(txn, contactId, 100);
-		assertTrue(ids.isEmpty());
-
-		// Adding a status with seen = false should make the message sendable
-		db.addStatus(txn, contactId, messageId, false, false);
-		ids = db.getMessagesToSend(txn, contactId, ONE_MEGABYTE);
+		// The contact has not seen the message, so it should be sendable
+		Collection<MessageId> ids =
+				db.getMessagesToSend(txn, contactId, ONE_MEGABYTE);
 		assertEquals(Collections.singletonList(messageId), ids);
 		ids = db.getMessagesToOffer(txn, contactId, 100);
 		assertEquals(Collections.singletonList(messageId), ids);
@@ -220,8 +213,7 @@ public class H2DatabaseTest extends BrambleTestCase {
 				true, true));
 		db.addGroup(txn, group);
 		db.addGroupVisibility(txn, contactId, groupId, true);
-		db.addMessage(txn, message, UNKNOWN, true);
-		db.addStatus(txn, contactId, messageId, false, false);
+		db.addMessage(txn, message, UNKNOWN, true, null);
 
 		// The message has not been validated, so it should not be sendable
 		Collection<MessageId> ids = db.getMessagesToSend(txn, contactId,
@@ -265,8 +257,7 @@ public class H2DatabaseTest extends BrambleTestCase {
 		assertEquals(contactId, db.addContact(txn, author, localAuthorId,
 				true, true));
 		db.addGroup(txn, group);
-		db.addMessage(txn, message, DELIVERED, true);
-		db.addStatus(txn, contactId, messageId, false, false);
+		db.addMessage(txn, message, DELIVERED, true, null);
 
 		// The group is invisible, so the message should not be sendable
 		Collection<MessageId> ids = db.getMessagesToSend(txn, contactId,
@@ -318,8 +309,7 @@ public class H2DatabaseTest extends BrambleTestCase {
 				true, true));
 		db.addGroup(txn, group);
 		db.addGroupVisibility(txn, contactId, groupId, true);
-		db.addMessage(txn, message, DELIVERED, false);
-		db.addStatus(txn, contactId, messageId, false, false);
+		db.addMessage(txn, message, DELIVERED, false, null);
 
 		// The message is not shared, so it should not be sendable
 		Collection<MessageId> ids = db.getMessagesToSend(txn, contactId,
@@ -350,8 +340,7 @@ public class H2DatabaseTest extends BrambleTestCase {
 				true, true));
 		db.addGroup(txn, group);
 		db.addGroupVisibility(txn, contactId, groupId, true);
-		db.addMessage(txn, message, DELIVERED, true);
-		db.addStatus(txn, contactId, messageId, false, false);
+		db.addMessage(txn, message, DELIVERED, true, null);
 
 		// The message is sendable, but too large to send
 		Collection<MessageId> ids = db.getMessagesToSend(txn, contactId,
@@ -381,12 +370,8 @@ public class H2DatabaseTest extends BrambleTestCase {
 		// Add some messages to ack
 		MessageId messageId1 = new MessageId(TestUtils.getRandomId());
 		Message message1 = new Message(messageId1, groupId, timestamp, raw);
-		db.addMessage(txn, message, DELIVERED, true);
-		db.addStatus(txn, contactId, messageId, false, true);
-		db.raiseAckFlag(txn, contactId, messageId);
-		db.addMessage(txn, message1, DELIVERED, true);
-		db.addStatus(txn, contactId, messageId1, false, true);
-		db.raiseAckFlag(txn, contactId, messageId1);
+		db.addMessage(txn, message, DELIVERED, true, contactId);
+		db.addMessage(txn, message1, DELIVERED, true, contactId);
 
 		// Both message IDs should be returned
 		Collection<MessageId> ids = db.getMessagesToAck(txn, contactId, 1234);
@@ -399,6 +384,14 @@ public class H2DatabaseTest extends BrambleTestCase {
 		assertEquals(Collections.emptyList(), db.getMessagesToAck(txn,
 				contactId, 1234));
 
+		// Raise the ack flag again
+		db.raiseAckFlag(txn, contactId, messageId);
+		db.raiseAckFlag(txn, contactId, messageId1);
+
+		// Both message IDs should be returned
+		ids = db.getMessagesToAck(txn, contactId, 1234);
+		assertEquals(Arrays.asList(messageId, messageId1), ids);
+
 		db.commitTransaction(txn);
 		db.close();
 	}
@@ -414,8 +407,7 @@ public class H2DatabaseTest extends BrambleTestCase {
 				true, true));
 		db.addGroup(txn, group);
 		db.addGroupVisibility(txn, contactId, groupId, true);
-		db.addMessage(txn, message, DELIVERED, true);
-		db.addStatus(txn, contactId, messageId, false, false);
+		db.addMessage(txn, message, DELIVERED, true, null);
 
 		// Retrieve the message from the database and mark it as sent
 		Collection<MessageId> ids = db.getMessagesToSend(txn, contactId,
@@ -456,7 +448,7 @@ public class H2DatabaseTest extends BrambleTestCase {
 		// Storing a message should reduce the free space
 		Connection txn = db.startTransaction();
 		db.addGroup(txn, group);
-		db.addMessage(txn, message, DELIVERED, true);
+		db.addMessage(txn, message, DELIVERED, true, null);
 		db.commitTransaction(txn);
 		assertTrue(db.getFreeSpace() < free);
 
@@ -604,15 +596,14 @@ public class H2DatabaseTest extends BrambleTestCase {
 		Database<Connection> db = open(false);
 		Connection txn = db.startTransaction();
 
-		// Add a contact, a group and a message
+		// Add a contact, an invisible group and a message
 		db.addLocalAuthor(txn, localAuthor);
 		assertEquals(contactId, db.addContact(txn, author, localAuthorId,
 				true, true));
 		db.addGroup(txn, group);
-		db.addMessage(txn, message, DELIVERED, true);
-		db.addStatus(txn, contactId, messageId, false, false);
+		db.addMessage(txn, message, DELIVERED, true, null);
 
-		// The group is not visible
+		// The group is not visible so the message should not be visible
 		assertFalse(db.containsVisibleMessage(txn, contactId, messageId));
 
 		db.commitTransaction(txn);
@@ -632,31 +623,31 @@ public class H2DatabaseTest extends BrambleTestCase {
 
 		// The group should not be visible to the contact
 		assertEquals(INVISIBLE, db.getGroupVisibility(txn, contactId, groupId));
-		assertEquals(Collections.emptyList(),
+		assertEquals(Collections.emptyMap(),
 				db.getGroupVisibility(txn, groupId));
 
 		// Make the group visible to the contact
 		db.addGroupVisibility(txn, contactId, groupId, false);
 		assertEquals(VISIBLE, db.getGroupVisibility(txn, contactId, groupId));
-		assertEquals(Collections.singletonList(contactId),
+		assertEquals(Collections.singletonMap(contactId, false),
 				db.getGroupVisibility(txn, groupId));
 
 		// Share the group with the contact
 		db.setGroupVisibility(txn, contactId, groupId, true);
 		assertEquals(SHARED, db.getGroupVisibility(txn, contactId, groupId));
-		assertEquals(Collections.singletonList(contactId),
+		assertEquals(Collections.singletonMap(contactId, true),
 				db.getGroupVisibility(txn, groupId));
 
 		// Unshare the group with the contact
 		db.setGroupVisibility(txn, contactId, groupId, false);
 		assertEquals(VISIBLE, db.getGroupVisibility(txn, contactId, groupId));
-		assertEquals(Collections.singletonList(contactId),
+		assertEquals(Collections.singletonMap(contactId, false),
 				db.getGroupVisibility(txn, groupId));
 
 		// Make the group invisible again
 		db.removeGroupVisibility(txn, contactId, groupId);
 		assertEquals(INVISIBLE, db.getGroupVisibility(txn, contactId, groupId));
-		assertEquals(Collections.emptyList(),
+		assertEquals(Collections.emptyMap(),
 				db.getGroupVisibility(txn, groupId));
 
 		db.commitTransaction(txn);
@@ -876,8 +867,7 @@ public class H2DatabaseTest extends BrambleTestCase {
 		// Remove some of the offered messages and count again
 		List<MessageId> half = ids.subList(0, 5);
 		db.removeOfferedMessages(txn, contactId, half);
-		assertTrue(db.removeOfferedMessage(txn, contactId, ids.get(5)));
-		assertEquals(4, db.countOfferedMessages(txn, contactId));
+		assertEquals(5, db.countOfferedMessages(txn, contactId));
 
 		db.commitTransaction(txn);
 		db.close();
@@ -928,7 +918,7 @@ public class H2DatabaseTest extends BrambleTestCase {
 
 		// Add a group and a message
 		db.addGroup(txn, group);
-		db.addMessage(txn, message, DELIVERED, true);
+		db.addMessage(txn, message, DELIVERED, true, null);
 
 		// Attach some metadata to the message
 		Metadata metadata = new Metadata();
@@ -999,7 +989,7 @@ public class H2DatabaseTest extends BrambleTestCase {
 
 		// Add a group and a message
 		db.addGroup(txn, group);
-		db.addMessage(txn, message, DELIVERED, true);
+		db.addMessage(txn, message, DELIVERED, true, null);
 
 		// Attach some metadata to the message
 		Metadata metadata = new Metadata();
@@ -1060,8 +1050,8 @@ public class H2DatabaseTest extends BrambleTestCase {
 
 		// Add a group and two messages
 		db.addGroup(txn, group);
-		db.addMessage(txn, message, DELIVERED, true);
-		db.addMessage(txn, message1, DELIVERED, true);
+		db.addMessage(txn, message, DELIVERED, true, null);
+		db.addMessage(txn, message1, DELIVERED, true, null);
 
 		// Attach some metadata to the messages
 		Metadata metadata = new Metadata();
@@ -1164,8 +1154,8 @@ public class H2DatabaseTest extends BrambleTestCase {
 
 		// Add a group and two messages
 		db.addGroup(txn, group);
-		db.addMessage(txn, message, DELIVERED, true);
-		db.addMessage(txn, message1, DELIVERED, true);
+		db.addMessage(txn, message, DELIVERED, true, null);
+		db.addMessage(txn, message1, DELIVERED, true, null);
 
 		// Attach some metadata to the messages
 		Metadata metadata = new Metadata();
@@ -1239,9 +1229,9 @@ public class H2DatabaseTest extends BrambleTestCase {
 
 		// Add a group and some messages
 		db.addGroup(txn, group);
-		db.addMessage(txn, message, PENDING, true);
-		db.addMessage(txn, message1, DELIVERED, true);
-		db.addMessage(txn, message2, INVALID, true);
+		db.addMessage(txn, message, PENDING, true, contactId);
+		db.addMessage(txn, message1, DELIVERED, true, contactId);
+		db.addMessage(txn, message2, INVALID, true, contactId);
 
 		// Add dependencies
 		db.addMessageDependency(txn, groupId, messageId, messageId1);
@@ -1308,7 +1298,7 @@ public class H2DatabaseTest extends BrambleTestCase {
 
 		// Add a group and a message
 		db.addGroup(txn, group);
-		db.addMessage(txn, message, PENDING, true);
+		db.addMessage(txn, message, PENDING, true, contactId);
 
 		// Add a second group
 		GroupId groupId1 = new GroupId(TestUtils.getRandomId());
@@ -1319,7 +1309,7 @@ public class H2DatabaseTest extends BrambleTestCase {
 		// Add a message to the second group
 		MessageId messageId1 = new MessageId(TestUtils.getRandomId());
 		Message message1 = new Message(messageId1, groupId1, timestamp, raw);
-		db.addMessage(txn, message1, DELIVERED, true);
+		db.addMessage(txn, message1, DELIVERED, true, contactId);
 
 		// Create an ID for a missing message
 		MessageId messageId2 = new MessageId(TestUtils.getRandomId());
@@ -1327,7 +1317,7 @@ public class H2DatabaseTest extends BrambleTestCase {
 		// Add another message to the first group
 		MessageId messageId3 = new MessageId(TestUtils.getRandomId());
 		Message message3 = new Message(messageId3, groupId, timestamp, raw);
-		db.addMessage(txn, message3, DELIVERED, true);
+		db.addMessage(txn, message3, DELIVERED, true, contactId);
 
 		// Add dependencies between the messages
 		db.addMessageDependency(txn, groupId, messageId, messageId1);
@@ -1374,10 +1364,10 @@ public class H2DatabaseTest extends BrambleTestCase {
 
 		// Add a group and some messages with different states
 		db.addGroup(txn, group);
-		db.addMessage(txn, m1, UNKNOWN, true);
-		db.addMessage(txn, m2, INVALID, true);
-		db.addMessage(txn, m3, PENDING, true);
-		db.addMessage(txn, m4, DELIVERED, true);
+		db.addMessage(txn, m1, UNKNOWN, true, contactId);
+		db.addMessage(txn, m2, INVALID, true, contactId);
+		db.addMessage(txn, m3, PENDING, true, contactId);
+		db.addMessage(txn, m4, DELIVERED, true, contactId);
 
 		Collection<MessageId> result;
 
@@ -1411,10 +1401,10 @@ public class H2DatabaseTest extends BrambleTestCase {
 
 		// Add a group and some messages
 		db.addGroup(txn, group);
-		db.addMessage(txn, m1, DELIVERED, true);
-		db.addMessage(txn, m2, DELIVERED, false);
-		db.addMessage(txn, m3, DELIVERED, false);
-		db.addMessage(txn, m4, DELIVERED, true);
+		db.addMessage(txn, m1, DELIVERED, true, contactId);
+		db.addMessage(txn, m2, DELIVERED, false, contactId);
+		db.addMessage(txn, m3, DELIVERED, false, contactId);
+		db.addMessage(txn, m4, DELIVERED, true, contactId);
 
 		// Introduce dependencies between the messages
 		db.addMessageDependency(txn, groupId, mId1, mId2);
@@ -1443,8 +1433,7 @@ public class H2DatabaseTest extends BrambleTestCase {
 				true, true));
 		db.addGroup(txn, group);
 		db.addGroupVisibility(txn, contactId, groupId, true);
-		db.addMessage(txn, message, DELIVERED, true);
-		db.addStatus(txn, contactId, messageId, false, false);
+		db.addMessage(txn, message, DELIVERED, true, null);
 
 		// The message should not be sent or seen
 		MessageStatus status = db.getMessageStatus(txn, contactId, messageId);
@@ -1546,8 +1535,7 @@ public class H2DatabaseTest extends BrambleTestCase {
 				true, true));
 		db.addGroup(txn, group);
 		db.addGroupVisibility(txn, contactId, groupId, true);
-		db.addMessage(txn, message, DELIVERED, true);
-		db.addStatus(txn, contactId, messageId, false, false);
+		db.addMessage(txn, message, DELIVERED, true, null);
 
 		// The message should be visible to the contact
 		assertTrue(db.containsVisibleMessage(txn, contactId, messageId));
@@ -1621,7 +1609,7 @@ public class H2DatabaseTest extends BrambleTestCase {
 
 		// Add a group and a message
 		db.addGroup(txn, group);
-		db.addMessage(txn, message, UNKNOWN, false);
+		db.addMessage(txn, message, UNKNOWN, false, contactId);
 
 		// Walk the message through the validation and delivery states
 		assertEquals(UNKNOWN, db.getMessageState(txn, messageId));
@@ -1647,14 +1635,13 @@ public class H2DatabaseTest extends BrambleTestCase {
 		assertEquals(contactId, db.addContact(txn, author, localAuthor.getId(),
 				true, true));
 		db.addGroup(txn, group);
-		db.addMessage(txn, message, UNKNOWN, false);
+		db.addMessage(txn, message, UNKNOWN, false, null);
 
 		// There should be no messages to send
 		assertEquals(Long.MAX_VALUE, db.getNextSendTime(txn, contactId));
 
 		// Share the group with the contact - still no messages to send
 		db.addGroupVisibility(txn, contactId, groupId, true);
-		db.addStatus(txn, contactId, messageId, false, false);
 		assertEquals(Long.MAX_VALUE, db.getNextSendTime(txn, contactId));
 
 		// Set the message's state to DELIVERED - still no messages to send

bramble-core/src/test/java/org/briarproject/bramble/db/Migration30_31Test.java

@@ -24,6 +24,7 @@ import static junit.framework.TestCase.assertNotNull;
 import static junit.framework.TestCase.assertTrue;
 import static org.briarproject.bramble.api.sync.ValidationManager.State.DELIVERED;
 import static org.briarproject.bramble.api.sync.ValidationManager.State.UNKNOWN;
+import static org.briarproject.bramble.test.TestUtils.getMessage;
 import static org.briarproject.bramble.test.TestUtils.getRandomBytes;
 import static org.briarproject.bramble.test.TestUtils.getRandomId;
 import static org.briarproject.bramble.util.StringUtils.getRandomString;
@@ -34,7 +35,7 @@ public class Migration30_31Test extends BrambleTestCase {
 
 	private static final String CREATE_GROUPS_STUB =
 			"CREATE TABLE groups"
-					+ " (groupID BINARY(32) NOT NULL,"
+					+ " (groupId BINARY(32) NOT NULL,"
 					+ " PRIMARY KEY (groupId))";
 
 	private static final String CREATE_MESSAGES =
@@ -66,8 +67,8 @@ public class Migration30_31Test extends BrambleTestCase {
 	private final String url = "jdbc:h2:" + db.getAbsolutePath();
 	private final GroupId groupId = new GroupId(getRandomId());
 	private final GroupId groupId1 = new GroupId(getRandomId());
-	private final Message message = TestUtils.getMessage(groupId);
-	private final Message message1 = TestUtils.getMessage(groupId1);
+	private final Message message = getMessage(groupId);
+	private final Message message1 = getMessage(groupId1);
 	private final Metadata meta = new Metadata(), meta1 = new Metadata();
 
 	private Connection connection = null;

bramble-core/src/test/java/org/briarproject/bramble/db/Migration31_32Test.java

@@ -0,0 +1,369 @@
+package org.briarproject.bramble.db;
+
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.sync.GroupId;
+import org.briarproject.bramble.api.sync.Message;
+import org.briarproject.bramble.api.sync.MessageId;
+import org.briarproject.bramble.api.sync.ValidationManager.State;
+import org.briarproject.bramble.test.BrambleTestCase;
+import org.briarproject.bramble.test.TestUtils;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.io.File;
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.sql.Statement;
+
+import static java.sql.Types.BINARY;
+import static junit.framework.Assert.assertFalse;
+import static junit.framework.TestCase.assertTrue;
+import static org.briarproject.bramble.api.sync.ValidationManager.State.DELIVERED;
+import static org.briarproject.bramble.api.sync.ValidationManager.State.UNKNOWN;
+import static org.briarproject.bramble.test.TestUtils.getMessage;
+import static org.briarproject.bramble.test.TestUtils.getRandomId;
+import static org.junit.Assert.assertEquals;
+
+public class Migration31_32Test extends BrambleTestCase {
+
+	private static final String CREATE_GROUPS_STUB =
+			"CREATE TABLE groups"
+					+ " (groupId BINARY(32) NOT NULL,"
+					+ " PRIMARY KEY (groupId))";
+
+	private static final String CREATE_CONTACTS_STUB =
+			"CREATE TABLE contacts"
+					+ " (contactId INT NOT NULL,"
+					+ " PRIMARY KEY (contactId))";
+
+	private static final String CREATE_GROUP_VISIBILITIES_STUB =
+			"CREATE TABLE groupVisibilities"
+					+ " (contactId INT NOT NULL,"
+					+ " groupId BINARY(32) NOT NULL,"
+					+ " shared BOOLEAN NOT NULL,"
+					+ " PRIMARY KEY (contactId, groupId))";
+
+	private static final String CREATE_MESSAGES =
+			"CREATE TABLE messages"
+					+ " (messageId BINARY(32) NOT NULL,"
+					+ " groupId BINARY(32) NOT NULL,"
+					+ " timestamp BIGINT NOT NULL,"
+					+ " state INT NOT NULL,"
+					+ " shared BOOLEAN NOT NULL,"
+					+ " length INT NOT NULL,"
+					+ " raw BLOB," // Null if message has been deleted
+					+ " PRIMARY KEY (messageId),"
+					+ " FOREIGN KEY (groupId)"
+					+ " REFERENCES groups (groupId)"
+					+ " ON DELETE CASCADE)";
+
+	private static final String CREATE_STATUSES_31 =
+			"CREATE TABLE statuses"
+					+ " (messageId BINARY(32) NOT NULL,"
+					+ " contactId INT NOT NULL,"
+					+ " ack BOOLEAN NOT NULL,"
+					+ " seen BOOLEAN NOT NULL,"
+					+ " requested BOOLEAN NOT NULL,"
+					+ " expiry BIGINT NOT NULL,"
+					+ " txCount INT NOT NULL,"
+					+ " PRIMARY KEY (messageId, contactId),"
+					+ " FOREIGN KEY (messageId)"
+					+ " REFERENCES messages (messageId)"
+					+ " ON DELETE CASCADE,"
+					+ " FOREIGN KEY (contactId)"
+					+ " REFERENCES contacts (contactId)"
+					+ " ON DELETE CASCADE)";
+
+	private final File testDir = TestUtils.getTestDirectory();
+	private final File db = new File(testDir, "db");
+	private final String url = "jdbc:h2:" + db.getAbsolutePath();
+	private final GroupId groupId = new GroupId(getRandomId());
+	private final GroupId groupId1 = new GroupId(getRandomId());
+	private final ContactId contactId = new ContactId(123);
+	private final ContactId contactId1 = new ContactId(234);
+	private final Message message = getMessage(groupId);
+	private final Message message1 = getMessage(groupId1);
+	private final Message message2 = getMessage(groupId1);
+
+	private Connection connection = null;
+
+	@Before
+	public void setUp() throws Exception {
+		assertTrue(testDir.mkdirs());
+		Class.forName("org.h2.Driver");
+		connection = DriverManager.getConnection(url);
+	}
+
+	@After
+	public void tearDown() throws Exception {
+		if (connection != null) connection.close();
+		TestUtils.deleteTestDirectory(testDir);
+	}
+
+	@Test
+	public void testMigration() throws Exception {
+		try {
+			Statement s = connection.createStatement();
+			s.execute(CREATE_GROUPS_STUB);
+			s.execute(CREATE_CONTACTS_STUB);
+			s.execute(CREATE_GROUP_VISIBILITIES_STUB);
+			s.execute(CREATE_MESSAGES);
+			s.execute(CREATE_STATUSES_31);
+			s.close();
+
+			addGroup(groupId);
+			addMessage(message, DELIVERED, true, false);
+
+			addGroup(groupId1);
+			addMessage(message1, UNKNOWN, false, false);
+			addMessage(message2, DELIVERED, true, true);
+
+			addContact(contactId);
+
+			addGroupVisibility(contactId, groupId, true);
+			addStatus31(message.getId(), contactId);
+
+			addGroupVisibility(contactId, groupId1, false);
+			addStatus31(message1.getId(), contactId);
+			addStatus31(message2.getId(), contactId);
+
+			addContact(contactId1);
+
+			addGroupVisibility(contactId1, groupId1, true);
+			addStatus31(message1.getId(), contactId1);
+			addStatus31(message2.getId(), contactId1);
+
+			new Migration31_32().migrate(connection);
+
+			assertTrue(containsStatus(message.getId(), contactId));
+			Status32 status = getStatus32(message.getId(), contactId);
+			assertEquals(groupId, status.groupId);
+			assertEquals(message.getTimestamp(), status.timestamp);
+			assertEquals(message.getLength(), status.length);
+			assertEquals(DELIVERED, status.state);
+			assertTrue(status.groupShared);
+			assertTrue(status.messageShared);
+			assertFalse(status.deleted);
+
+			assertTrue(containsStatus(message1.getId(), contactId));
+			status = getStatus32(message1.getId(), contactId);
+			assertEquals(groupId1, status.groupId);
+			assertEquals(message1.getTimestamp(), status.timestamp);
+			assertEquals(message1.getLength(), status.length);
+			assertEquals(UNKNOWN, status.state);
+			assertFalse(status.groupShared);
+			assertFalse(status.messageShared);
+			assertFalse(status.deleted);
+
+			assertTrue(containsStatus(message2.getId(), contactId));
+			status = getStatus32(message2.getId(), contactId);
+			assertEquals(groupId1, status.groupId);
+			assertEquals(message2.getTimestamp(), status.timestamp);
+			assertEquals(message2.getLength(), status.length);
+			assertEquals(DELIVERED, status.state);
+			assertFalse(status.groupShared);
+			assertTrue(status.messageShared);
+			assertTrue(status.deleted);
+
+			assertFalse(containsStatus(message.getId(), contactId1));
+
+			assertTrue(containsStatus(message1.getId(), contactId1));
+			status = getStatus32(message1.getId(), contactId1);
+			assertEquals(groupId1, status.groupId);
+			assertEquals(message1.getTimestamp(), status.timestamp);
+			assertEquals(message1.getLength(), status.length);
+			assertEquals(UNKNOWN, status.state);
+			assertTrue(status.groupShared);
+			assertFalse(status.messageShared);
+			assertFalse(status.deleted);
+
+			assertTrue(containsStatus(message2.getId(), contactId1));
+			status = getStatus32(message2.getId(), contactId1);
+			assertEquals(groupId1, status.groupId);
+			assertEquals(message2.getTimestamp(), status.timestamp);
+			assertEquals(message2.getLength(), status.length);
+			assertEquals(DELIVERED, status.state);
+			assertTrue(status.groupShared);
+			assertTrue(status.messageShared);
+			assertTrue(status.deleted);
+		} catch (SQLException e) {
+			connection.close();
+			throw e;
+		}
+	}
+
+	private void addGroup(GroupId g) throws SQLException {
+		PreparedStatement ps = null;
+		try {
+			String sql = "INSERT INTO groups (groupId) VALUES (?)";
+			ps = connection.prepareStatement(sql);
+			ps.setBytes(1, g.getBytes());
+			int affected = ps.executeUpdate();
+			if (affected != 1) throw new DbStateException();
+			ps.close();
+		} catch (SQLException e) {
+			if (ps != null) ps.close();
+			throw e;
+		}
+	}
+
+	private void addContact(ContactId c) throws SQLException {
+		PreparedStatement ps = null;
+		try {
+			String sql = "INSERT INTO contacts (contactId) VALUES (?)";
+			ps = connection.prepareStatement(sql);
+			ps.setInt(1, c.getInt());
+			int affected = ps.executeUpdate();
+			if (affected != 1) throw new DbStateException();
+			ps.close();
+		} catch (SQLException e) {
+			if (ps != null) ps.close();
+			throw e;
+		}
+	}
+
+	private void addGroupVisibility(ContactId c, GroupId g, boolean shared)
+			throws SQLException {
+		PreparedStatement ps = null;
+		try {
+			String sql = "INSERT INTO groupVisibilities"
+					+ " (contactId, groupId, shared) VALUES (?, ?, ?)";
+			ps = connection.prepareStatement(sql);
+			ps.setInt(1, c.getInt());
+			ps.setBytes(2, g.getBytes());
+			ps.setBoolean(3, shared);
+			int affected = ps.executeUpdate();
+			if (affected != 1) throw new DbStateException();
+			ps.close();
+		} catch (SQLException e) {
+			if (ps != null) ps.close();
+			throw e;
+		}
+	}
+
+	private void addMessage(Message m, State state, boolean shared,
+			boolean deleted) throws SQLException {
+		PreparedStatement ps = null;
+		try {
+			String sql = "INSERT INTO messages (messageId, groupId, timestamp,"
+					+ " state, shared, length, raw)"
+					+ " VALUES (?, ?, ?, ?, ?, ?, ?)";
+			ps = connection.prepareStatement(sql);
+			ps.setBytes(1, m.getId().getBytes());
+			ps.setBytes(2, m.getGroupId().getBytes());
+			ps.setLong(3, m.getTimestamp());
+			ps.setInt(4, state.getValue());
+			ps.setBoolean(5, shared);
+			byte[] raw = m.getRaw();
+			ps.setInt(6, raw.length);
+			if (deleted) ps.setNull(7, BINARY);
+			else ps.setBytes(7, raw);
+			int affected = ps.executeUpdate();
+			if (affected != 1) throw new DbStateException();
+			ps.close();
+		} catch (SQLException e) {
+			if (ps != null) ps.close();
+			throw e;
+		}
+	}
+
+	private void addStatus31(MessageId m, ContactId c) throws SQLException {
+		PreparedStatement ps = null;
+		try {
+			String sql = "INSERT INTO statuses (messageId, contactId, ack,"
+					+ " seen, requested, expiry, txCount)"
+					+ " VALUES (?, ?, FALSE, FALSE, FALSE, 0, 0)";
+			ps = connection.prepareStatement(sql);
+			ps.setBytes(1, m.getBytes());
+			ps.setInt(2, c.getInt());
+			int affected = ps.executeUpdate();
+			if (affected != 1) throw new DbStateException();
+			ps.close();
+		} catch (SQLException e) {
+			if (ps != null) ps.close();
+			throw e;
+		}
+	}
+
+	private boolean containsStatus(MessageId m, ContactId c)
+			throws SQLException {
+		PreparedStatement ps = null;
+		ResultSet rs = null;
+		try {
+			String sql = "SELECT COUNT (*) FROM statuses"
+					+ " WHERE messageId = ? AND contactId = ?";
+			ps = connection.prepareStatement(sql);
+			ps.setBytes(1, m.getBytes());
+			ps.setInt(2, c.getInt());
+			rs = ps.executeQuery();
+			if (!rs.next()) throw new DbStateException();
+			int count = rs.getInt(1);
+			if (count < 0 || count > 1) throw new DbStateException();
+			if (rs.next()) throw new DbStateException();
+			rs.close();
+			ps.close();
+			return count > 0;
+		} catch (SQLException e) {
+			if (rs != null) rs.close();
+			if (ps != null) ps.close();
+			throw e;
+		}
+	}
+
+	private Status32 getStatus32(MessageId m, ContactId c) throws SQLException {
+		PreparedStatement ps = null;
+		ResultSet rs = null;
+		try {
+			String sql = "SELECT groupId, timestamp, length, state,"
+					+ " groupShared, messageShared, deleted"
+					+ " FROM statuses"
+					+ " WHERE messageId = ? AND contactId = ?";
+			ps = connection.prepareStatement(sql);
+			ps.setBytes(1, m.getBytes());
+			ps.setInt(2, c.getInt());
+			rs = ps.executeQuery();
+			if (!rs.next()) throw new DbStateException();
+			GroupId groupId = new GroupId(rs.getBytes(1));
+			long timestamp = rs.getLong(2);
+			int length = rs.getInt(3);
+			State state = State.fromValue(rs.getInt(4));
+			boolean groupShared = rs.getBoolean(5);
+			boolean messageShared = rs.getBoolean(6);
+			boolean deleted = rs.getBoolean(7);
+			if (rs.next()) throw new DbStateException();
+			rs.close();
+			ps.close();
+			return new Status32(groupId, timestamp, length, state,
+					groupShared, messageShared, deleted);
+		} catch (SQLException e) {
+			if (rs != null) rs.close();
+			if (ps != null) ps.close();
+			throw e;
+		}
+	}
+
+	private static class Status32 {
+
+		private final GroupId groupId;
+		private final long timestamp;
+		private final int length;
+		private final State state;
+		private final boolean groupShared, messageShared, deleted;
+
+		private Status32(GroupId groupId, long timestamp, int length,
+				State state, boolean groupShared, boolean messageShared,
+				boolean deleted) {
+			this.groupId = groupId;
+			this.timestamp = timestamp;
+			this.length = length;
+			this.state = state;
+			this.groupShared = groupShared;
+			this.messageShared = messageShared;
+			this.deleted = deleted;
+		}
+	}
+}