Refactored SessionsTable#saveSession to an executable:

Affected:
- KillsTable#savePlayerKills
- WorldTimesTable#saveWorldTimes
- KillsTable and WorldTimesTable where execution contained duplication
  with LargeStoreQueries, mainly INSERT_STATEMENT and batch additions
- SessionCache#endSession now returns an Optional Session for future
  refactoring, when Logout transaction is being made.

Plan/common/src/main/java/com/djrapitops/plan/ShutdownHook.java

@@ -103,6 +103,7 @@ public class ShutdownHook extends Thread {
             if (!database.isOpen()) {
                 database.init();
             }
+            // TODO Create a server shutdown transaction.
             try {
                 database.save().session(uuid, session);
             } catch (DBOpException e) {

Plan/common/src/main/java/com/djrapitops/plan/db/sql/queries/DataStoreQueries.java

@@ -16,10 +16,13 @@
  */
 package com.djrapitops.plan.db.sql.queries;
 
+import com.djrapitops.plan.data.container.Session;
+import com.djrapitops.plan.data.store.keys.SessionKeys;
+import com.djrapitops.plan.data.time.GMTimes;
+import com.djrapitops.plan.db.access.ExecBatchStatement;
 import com.djrapitops.plan.db.access.ExecStatement;
 import com.djrapitops.plan.db.access.Executable;
-import com.djrapitops.plan.db.sql.tables.CommandUseTable;
+import com.djrapitops.plan.db.sql.tables.*;
-import com.djrapitops.plan.db.sql.tables.ServerTable;
 
 import java.sql.PreparedStatement;
 import java.sql.SQLException;
@@ -36,6 +39,13 @@ public class DataStoreQueries {
         /* static method class */
     }
 
+    /**
+     * Store the used command in the database.
+     *
+     * @param serverUUID  UUID of the Plan server.
+     * @param commandName Name of the command that was used.
+     * @return Executable, use inside a {@link com.djrapitops.plan.db.access.transactions.Transaction}
+     */
     public static Executable storeUsedCommandInformation(UUID serverUUID, String commandName) {
         return connection -> {
             if (!updateCommandUsage(serverUUID, commandName).execute(connection)) {
@@ -71,4 +81,52 @@ public class DataStoreQueries {
         };
     }
 
+    /**
+     * Store a finished session in the database.
+     *
+     * @param session Session, of which {@link Session#endSession(long)} has been called.
+     * @return Executable, use inside a {@link com.djrapitops.plan.db.access.transactions.Transaction}
+     * @throws IllegalArgumentException If {@link Session#endSession(long)} has not yet been called.
+     */
+    public static Executable storeSession(Session session) {
+        session.getValue(SessionKeys.END).orElseThrow(() -> new IllegalArgumentException("Attempted to save a session that has not ended."));
+        return connection -> {
+            storeSessionInformation(session).execute(connection);
+            storeSessionKills(session).execute(connection);
+            return storeSessionWorldTimes(session).execute(connection);
+        };
+    }
+
+    private static Executable storeSessionInformation(Session session) {
+        return new ExecStatement(SessionsTable.INSERT_STATEMENT) {
+            @Override
+            public void prepare(PreparedStatement statement) throws SQLException {
+                statement.setString(1, session.getUnsafe(SessionKeys.UUID).toString());
+                statement.setLong(2, session.getUnsafe(SessionKeys.START));
+                statement.setLong(3, session.getUnsafe(SessionKeys.END));
+                statement.setInt(4, session.getUnsafe(SessionKeys.DEATH_COUNT));
+                statement.setInt(5, session.getUnsafe(SessionKeys.MOB_KILL_COUNT));
+                statement.setLong(6, session.getUnsafe(SessionKeys.AFK_TIME));
+                statement.setString(7, session.getUnsafe(SessionKeys.SERVER_UUID).toString());
+            }
+        };
+    }
+
+    private static Executable storeSessionKills(Session session) {
+        return new ExecBatchStatement(KillsTable.INSERT_STATEMENT) {
+            @Override
+            public void prepare(PreparedStatement statement) throws SQLException {
+                KillsTable.addSessionKillsToBatch(statement, session);
+            }
+        };
+    }
+
+    private static Executable storeSessionWorldTimes(Session session) {
+        return new ExecBatchStatement(WorldTimesTable.INSERT_STATEMENT) {
+            @Override
+            public void prepare(PreparedStatement statement) throws SQLException {
+                WorldTimesTable.addSessionWorldTimesToBatch(statement, session, GMTimes.getGMKeyArray());
+            }
+        };
+    }
 }

Plan/common/src/main/java/com/djrapitops/plan/db/sql/queries/LargeStoreQueries.java

@@ -352,8 +352,7 @@ public class LargeStoreQueries {
         return connection -> {
             storeAllSessionsWithoutKillOrWorldData(sessions).execute(connection);
             storeSessionKillData(sessions).execute(connection);
-            storeSessionWorldTimeData(sessions).execute(connection);
+            return storeSessionWorldTimeData(sessions).execute(connection);
-            return false;
         };
     }
 
@@ -362,35 +361,11 @@ public class LargeStoreQueries {
             return Executable.empty();
         }
 
-        String sql = "INSERT INTO " + KillsTable.TABLE_NAME + " ("
+        return new ExecBatchStatement(KillsTable.INSERT_STATEMENT) {
-                + KillsTable.SESSION_ID + ", "
-                + KillsTable.KILLER_UUID + ", "
-                + KillsTable.VICTIM_UUID + ", "
-                + KillsTable.SERVER_UUID + ", "
-                + KillsTable.DATE + ", "
-                + KillsTable.WEAPON
-                + ") VALUES (" + SessionsTable.SELECT_SESSION_ID_STATEMENT + ", ?, ?, ?, ?, ?)";
-
-        return new ExecBatchStatement(sql) {
             @Override
             public void prepare(PreparedStatement statement) throws SQLException {
                 for (Session session : sessions) {
-                    UUID uuid = session.getUnsafe(SessionKeys.UUID);
+                    KillsTable.addSessionKillsToBatch(statement, session);
-                    UUID serverUUID = session.getUnsafe(SessionKeys.SERVER_UUID);
-                    for (PlayerKill kill : session.getPlayerKills()) {
-                        // Session ID select statement
-                        statement.setString(1, uuid.toString());
-                        statement.setString(2, serverUUID.toString());
-                        statement.setLong(3, session.getUnsafe(SessionKeys.START));
-                        statement.setLong(4, session.getUnsafe(SessionKeys.END));
-
-                        statement.setString(5, uuid.toString());
-                        statement.setString(6, kill.getVictim().toString());
-                        statement.setString(7, serverUUID.toString());
-                        statement.setLong(8, kill.getDate());
-                        statement.setString(9, kill.getWeapon());
-                        statement.addBatch();
-                    }
                 }
             }
         };
@@ -401,51 +376,13 @@ public class LargeStoreQueries {
             return Executable.empty();
         }
 
-        String sql = "INSERT INTO " + WorldTimesTable.TABLE_NAME + " (" +
+        return new ExecBatchStatement(WorldTimesTable.INSERT_STATEMENT) {
-                WorldTimesTable.SESSION_ID + ", " +
-                WorldTimesTable.WORLD_ID + ", " +
-                WorldTimesTable.USER_UUID + ", " +
-                WorldTimesTable.SERVER_UUID + ", " +
-                WorldTimesTable.SURVIVAL + ", " +
-                WorldTimesTable.CREATIVE + ", " +
-                WorldTimesTable.ADVENTURE + ", " +
-                WorldTimesTable.SPECTATOR +
-                ") VALUES ( " +
-                SessionsTable.SELECT_SESSION_ID_STATEMENT + ", " +
-                WorldTable.SELECT_WORLD_ID_STATEMENT + ", " +
-                "?, ?, ?, ?, ?, ?)";
-
-        return new ExecBatchStatement(sql) {
             @Override
             public void prepare(PreparedStatement statement) throws SQLException {
                 String[] gms = GMTimes.getGMKeyArray();
 
                 for (Session session : sessions) {
-                    UUID uuid = session.getUnsafe(SessionKeys.UUID);
+                    WorldTimesTable.addSessionWorldTimesToBatch(statement, session, gms);
-                    UUID serverUUID = session.getUnsafe(SessionKeys.SERVER_UUID);
-                    Map<String, GMTimes> worldTimes = session.getUnsafe(SessionKeys.WORLD_TIMES).getWorldTimes();
-                    for (Map.Entry<String, GMTimes> worldTimesEntry : worldTimes.entrySet()) {
-                        String worldName = worldTimesEntry.getKey();
-                        GMTimes gmTimes = worldTimesEntry.getValue();
-
-                        // Session ID select statement
-                        statement.setString(1, uuid.toString());
-                        statement.setString(2, serverUUID.toString());
-                        statement.setLong(3, session.getUnsafe(SessionKeys.START));
-                        statement.setLong(4, session.getUnsafe(SessionKeys.END));
-
-                        // World ID select statement
-                        statement.setString(5, worldName);
-                        statement.setString(6, serverUUID.toString());
-
-                        statement.setString(7, uuid.toString());
-                        statement.setString(8, serverUUID.toString());
-                        statement.setLong(9, gmTimes.getTime(gms[0]));
-                        statement.setLong(10, gmTimes.getTime(gms[1]));
-                        statement.setLong(11, gmTimes.getTime(gms[2]));
-                        statement.setLong(12, gmTimes.getTime(gms[3]));
-                        statement.addBatch();
-                    }
                 }
             }
         };

Plan/common/src/main/java/com/djrapitops/plan/db/sql/tables/KillsTable.java

@@ -22,7 +22,6 @@ import com.djrapitops.plan.data.container.Session;
 import com.djrapitops.plan.data.store.keys.SessionKeys;
 import com.djrapitops.plan.db.DBType;
 import com.djrapitops.plan.db.SQLDB;
-import com.djrapitops.plan.db.access.ExecStatement;
 import com.djrapitops.plan.db.access.QueryStatement;
 import com.djrapitops.plan.db.patches.KillsOptimizationPatch;
 import com.djrapitops.plan.db.patches.KillsServerIDPatch;
@@ -30,7 +29,6 @@ import com.djrapitops.plan.db.patches.Version10Patch;
 import com.djrapitops.plan.db.sql.parsing.CreateTableParser;
 import com.djrapitops.plan.db.sql.parsing.Sql;
 import com.djrapitops.plan.db.sql.queries.LargeFetchQueries;
-import com.djrapitops.plugin.utilities.Verify;
 
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
@@ -63,24 +61,18 @@ public class KillsTable extends Table {
     public static final String WEAPON = "weapon";
     public static final String DATE = "date";
 
-    private final UsersTable usersTable;
+    public static final String INSERT_STATEMENT = "INSERT INTO " + TABLE_NAME + " ("
-
+            + SESSION_ID + ", "
-    public KillsTable(SQLDB db) {
-        super(TABLE_NAME, db);
-        usersTable = db.getUsersTable();
-        sessionsTable = db.getSessionsTable();
-        insertStatement = "INSERT INTO " + tableName + " ("
             + KILLER_UUID + ", "
             + VICTIM_UUID + ", "
             + SERVER_UUID + ", "
-                + SESSION_ID + ", "
             + DATE + ", "
             + WEAPON
-                + ") VALUES (?, ?, ?, ?, ?, ?)";
+            + ") VALUES (" + SessionsTable.SELECT_SESSION_ID_STATEMENT + ", ?, ?, ?, ?, ?)";
-    }
 
-    private final SessionsTable sessionsTable;
+    public KillsTable(SQLDB db) {
-    private String insertStatement;
+        super(TABLE_NAME, db);
+    }
 
     public static String createTableSQL(DBType dbType) {
         return CreateTableParser.create(TABLE_NAME, dbType)
@@ -95,17 +87,38 @@ public class KillsTable extends Table {
                 .toString();
     }
 
+    public static void addSessionKillsToBatch(PreparedStatement statement, Session session) throws SQLException {
+        UUID uuid = session.getUnsafe(SessionKeys.UUID);
+        UUID serverUUID = session.getUnsafe(SessionKeys.SERVER_UUID);
+
+        for (PlayerKill kill : session.getPlayerKills()) {
+            // Session ID select statement parameters
+            statement.setString(1, uuid.toString());
+            statement.setString(2, serverUUID.toString());
+            statement.setLong(3, session.getUnsafe(SessionKeys.START));
+            statement.setLong(4, session.getUnsafe(SessionKeys.END));
+
+            // Kill data
+            statement.setString(5, uuid.toString());
+            statement.setString(6, kill.getVictim().toString());
+            statement.setString(7, serverUUID.toString());
+            statement.setLong(8, kill.getDate());
+            statement.setString(9, kill.getWeapon());
+            statement.addBatch();
+        }
+    }
+
     public void addKillsToSessions(UUID uuid, Map<Integer, Session> sessions) {
-        String usersUUIDColumn = usersTable + "." + UsersTable.USER_UUID;
+        String usersUUIDColumn = UsersTable.TABLE_NAME + "." + UsersTable.USER_UUID;
-        String usersNameColumn = usersTable + "." + UsersTable.USER_NAME + " as victim_name";
+        String usersNameColumn = UsersTable.TABLE_NAME + "." + UsersTable.USER_NAME + " as victim_name";
         String sql = "SELECT " +
                 SESSION_ID + ", " +
                 DATE + ", " +
                 WEAPON + ", " +
                 VICTIM_UUID + ", " +
                 usersNameColumn +
-                " FROM " + tableName +
+                " FROM " + TABLE_NAME +
-                " INNER JOIN " + usersTable + " on " + usersUUIDColumn + "=" + VICTIM_UUID +
+                " INNER JOIN " + UsersTable.TABLE_NAME + " on " + usersUUIDColumn + "=" + VICTIM_UUID +
                 " WHERE " + KILLER_UUID + "=?";
 
         query(new QueryStatement<Object>(sql, 50000) {
@@ -134,16 +147,16 @@ public class KillsTable extends Table {
     }
 
     public void addDeathsToSessions(UUID uuid, Map<Integer, Session> sessions) {
-        String usersUUIDColumn = usersTable + "." + UsersTable.USER_UUID;
+        String usersUUIDColumn = UsersTable.TABLE_NAME + "." + UsersTable.USER_UUID;
-        String usersNameColumn = usersTable + "." + UsersTable.USER_NAME + " as killer_name";
+        String usersNameColumn = UsersTable.TABLE_NAME + "." + UsersTable.USER_NAME + " as killer_name";
         String sql = "SELECT " +
                 SESSION_ID + ", " +
                 DATE + ", " +
                 WEAPON + ", " +
                 KILLER_UUID + ", " +
                 usersNameColumn +
-                " FROM " + tableName +
+                " FROM " + TABLE_NAME +
-                " INNER JOIN " + usersTable + " on " + usersUUIDColumn + "=" + KILLER_UUID +
+                " INNER JOIN " + UsersTable.TABLE_NAME + " on " + usersUUIDColumn + "=" + KILLER_UUID +
                 " WHERE " + VICTIM_UUID + "=?";
 
         query(new QueryStatement<Object>(sql, 50000) {
@@ -171,34 +184,6 @@ public class KillsTable extends Table {
         });
     }
 
-    public void savePlayerKills(UUID uuid, int sessionID, List<PlayerKill> playerKills) {
-        if (Verify.isEmpty(playerKills)) {
-            return;
-        }
-
-        executeBatch(new ExecStatement(insertStatement) {
-            @Override
-            public void prepare(PreparedStatement statement) throws SQLException {
-                for (PlayerKill kill : playerKills) {
-                    UUID victim = kill.getVictim();
-                    long date = kill.getDate();
-                    String weapon = kill.getWeapon();
-                    if (Verify.containsNull(victim, uuid)) {
-                        continue;
-                    }
-
-                    statement.setString(1, uuid.toString());
-                    statement.setString(2, victim.toString());
-                    statement.setString(3, getServerUUID().toString());
-                    statement.setInt(4, sessionID);
-                    statement.setLong(5, date);
-                    statement.setString(6, weapon);
-                    statement.addBatch();
-                }
-            }
-        });
-    }
-
     public void addKillsToSessions(Map<UUID, Map<UUID, List<Session>>> map) {
         Map<Integer, List<PlayerKill>> playerKillsBySessionID = db.query(LargeFetchQueries.fetchAllPlayerKillDataBySessionID());
         for (UUID serverUUID : map.keySet()) {

Plan/common/src/main/java/com/djrapitops/plan/db/sql/tables/SessionsTable.java

@@ -20,7 +20,6 @@ import com.djrapitops.plan.data.container.Session;
 import com.djrapitops.plan.data.store.keys.SessionKeys;
 import com.djrapitops.plan.db.DBType;
 import com.djrapitops.plan.db.SQLDB;
-import com.djrapitops.plan.db.access.ExecStatement;
 import com.djrapitops.plan.db.access.QueryAllStatement;
 import com.djrapitops.plan.db.access.QueryStatement;
 import com.djrapitops.plan.db.patches.SessionAFKTimePatch;
@@ -93,79 +92,6 @@ public class SessionsTable extends Table {
                 .toString();
     }
 
-    /**
-     * Used to get the sessionID of a newly inserted row.
-     *
-     * @param uuid    UUID of the player
-     * @param session session inserted.
-     * @return ID of the inserted session or -1 if session has not been inserted.
-     */
-    private int getSessionID(UUID uuid, Session session) {
-        String sql = "SELECT " + ID + " FROM " + tableName +
-                " WHERE " + USER_UUID + "=?" +
-                " AND " + SESSION_START + "=?" +
-                " AND " + SESSION_END + "=?";
-
-        return query(new QueryStatement<Integer>(sql) {
-            @Override
-            public void prepare(PreparedStatement statement) throws SQLException {
-                statement.setString(1, uuid.toString());
-                statement.setLong(2, session.getUnsafe(SessionKeys.START));
-                statement.setLong(3, session.getValue(SessionKeys.END).orElse(System.currentTimeMillis()));
-            }
-
-            @Override
-            public Integer processResults(ResultSet set) throws SQLException {
-                if (set.next()) {
-                    return set.getInt(ID);
-                }
-                return -1;
-            }
-        });
-    }
-
-    /**
-     * Used to save a session, with all it's information into the database.
-     * <p>
-     * Also saves WorldTimes and Kills.
-     *
-     * @param uuid    UUID of the player.
-     * @param session Session of the player that has ended ({@code endSession} has been called)
-     */
-    public void saveSession(UUID uuid, Session session) {
-        saveSessionInformation(uuid, session);
-        int sessionID = getSessionID(uuid, session);
-        if (sessionID == -1) {
-            throw new IllegalStateException("Session was not Saved!");
-        }
-
-        db.getWorldTimesTable().saveWorldTimes(uuid, sessionID, session.getUnsafe(SessionKeys.WORLD_TIMES));
-        db.getKillsTable().savePlayerKills(uuid, sessionID, session.getPlayerKills());
-    }
-
-    /**
-     * Saves Session's Information to the Session Table.
-     * <p>
-     * Does not save Kills or WorldTimes.
-     *
-     * @param uuid    UUID of the player.
-     * @param session Session of the player that has ended ({@code endSession} has been called)
-     */
-    private void saveSessionInformation(UUID uuid, Session session) {
-        execute(new ExecStatement(INSERT_STATEMENT) {
-            @Override
-            public void prepare(PreparedStatement statement) throws SQLException {
-                statement.setString(1, uuid.toString());
-                statement.setLong(2, session.getUnsafe(SessionKeys.START));
-                statement.setLong(3, session.getUnsafe(SessionKeys.END));
-                statement.setInt(4, session.getUnsafe(SessionKeys.DEATH_COUNT));
-                statement.setInt(5, session.getUnsafe(SessionKeys.MOB_KILL_COUNT));
-                statement.setLong(6, session.getUnsafe(SessionKeys.AFK_TIME));
-                statement.setString(7, getServerUUID().toString());
-            }
-        });
-    }
-
     /**
      * Returns a Map containing Lists of sessions, key as ServerName.
      * <p>

Plan/common/src/main/java/com/djrapitops/plan/db/sql/tables/WorldTimesTable.java

@@ -22,7 +22,6 @@ import com.djrapitops.plan.data.time.GMTimes;
 import com.djrapitops.plan.data.time.WorldTimes;
 import com.djrapitops.plan.db.DBType;
 import com.djrapitops.plan.db.SQLDB;
-import com.djrapitops.plan.db.access.ExecStatement;
 import com.djrapitops.plan.db.access.QueryAllStatement;
 import com.djrapitops.plan.db.access.QueryStatement;
 import com.djrapitops.plan.db.patches.Version10Patch;
@@ -31,7 +30,6 @@ import com.djrapitops.plan.db.patches.WorldTimesSeverIDPatch;
 import com.djrapitops.plan.db.patches.WorldsServerIDPatch;
 import com.djrapitops.plan.db.sql.parsing.CreateTableParser;
 import com.djrapitops.plan.db.sql.parsing.Sql;
-import com.djrapitops.plugin.utilities.Verify;
 
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
@@ -65,26 +63,22 @@ public class WorldTimesTable extends Table {
     public static final String ADVENTURE = "adventure_time";
     public static final String SPECTATOR = "spectator_time";
 
-    private final WorldTable worldTable;
+    public static final String INSERT_STATEMENT = "INSERT INTO " + WorldTimesTable.TABLE_NAME + " (" +
-    private final SessionsTable sessionsTable;
+            WorldTimesTable.SESSION_ID + ", " +
-    private String insertStatement;
+            WorldTimesTable.WORLD_ID + ", " +
+            WorldTimesTable.USER_UUID + ", " +
+            WorldTimesTable.SERVER_UUID + ", " +
+            WorldTimesTable.SURVIVAL + ", " +
+            WorldTimesTable.CREATIVE + ", " +
+            WorldTimesTable.ADVENTURE + ", " +
+            WorldTimesTable.SPECTATOR +
+            ") VALUES ( " +
+            SessionsTable.SELECT_SESSION_ID_STATEMENT + ", " +
+            WorldTable.SELECT_WORLD_ID_STATEMENT + ", " +
+            "?, ?, ?, ?, ?, ?)";
 
     public WorldTimesTable(SQLDB db) {
         super(TABLE_NAME, db);
-        worldTable = db.getWorldTable();
-        sessionsTable = db.getSessionsTable();
-        insertStatement = "INSERT INTO " + tableName + " (" +
-                USER_UUID + ", " +
-                WORLD_ID + ", " +
-                SERVER_UUID + ", " +
-                SESSION_ID + ", " +
-                SURVIVAL + ", " +
-                CREATIVE + ", " +
-                ADVENTURE + ", " +
-                SPECTATOR +
-                ") VALUES (?, " +
-                WorldTable.SELECT_WORLD_ID_STATEMENT + ", " +
-                "?, ?, ?, ?, ?, ?)";
     }
 
     public static String createTableSQL(DBType dbType) {
@@ -103,9 +97,37 @@ public class WorldTimesTable extends Table {
                 .toString();
     }
 
+    public static void addSessionWorldTimesToBatch(PreparedStatement statement, Session session, String[] gms) throws SQLException {
+        UUID uuid = session.getUnsafe(SessionKeys.UUID);
+        UUID serverUUID = session.getUnsafe(SessionKeys.SERVER_UUID);
+        Map<String, GMTimes> worldTimes = session.getUnsafe(SessionKeys.WORLD_TIMES).getWorldTimes();
+        for (Map.Entry<String, GMTimes> worldTimesEntry : worldTimes.entrySet()) {
+            String worldName = worldTimesEntry.getKey();
+            GMTimes gmTimes = worldTimesEntry.getValue();
+
+            // Session ID select statement
+            statement.setString(1, uuid.toString());
+            statement.setString(2, serverUUID.toString());
+            statement.setLong(3, session.getUnsafe(SessionKeys.START));
+            statement.setLong(4, session.getUnsafe(SessionKeys.END));
+
+            // World ID select statement
+            statement.setString(5, worldName);
+            statement.setString(6, serverUUID.toString());
+
+            statement.setString(7, uuid.toString());
+            statement.setString(8, serverUUID.toString());
+            statement.setLong(9, gmTimes.getTime(gms[0]));
+            statement.setLong(10, gmTimes.getTime(gms[1]));
+            statement.setLong(11, gmTimes.getTime(gms[2]));
+            statement.setLong(12, gmTimes.getTime(gms[3]));
+            statement.addBatch();
+        }
+    }
+
     public void addWorldTimesToSessions(UUID uuid, Map<Integer, Session> sessions) {
-        String worldIDColumn = worldTable + "." + WorldTable.ID;
+        String worldIDColumn = WorldTable.TABLE_NAME + "." + WorldTable.ID;
-        String worldNameColumn = worldTable + "." + WorldTable.NAME + " as world_name";
+        String worldNameColumn = WorldTable.TABLE_NAME + "." + WorldTable.NAME + " as world_name";
         String sql = "SELECT " +
                 SESSION_ID + ", " +
                 SURVIVAL + ", " +
@@ -113,8 +135,8 @@ public class WorldTimesTable extends Table {
                 ADVENTURE + ", " +
                 SPECTATOR + ", " +
                 worldNameColumn +
-                " FROM " + tableName +
+                " FROM " + TABLE_NAME +
-                " INNER JOIN " + worldTable + " on " + worldIDColumn + "=" + WORLD_ID +
+                " INNER JOIN " + WorldTable.TABLE_NAME + " on " + worldIDColumn + "=" + WORLD_ID +
                 " WHERE " + USER_UUID + "=?";
 
         query(new QueryStatement<Object>(sql, 2000) {
@@ -151,50 +173,17 @@ public class WorldTimesTable extends Table {
         });
     }
 
-    public void saveWorldTimes(UUID uuid, int sessionID, WorldTimes worldTimes) {
-        Map<String, GMTimes> worldTimesMap = worldTimes.getWorldTimes();
-        if (Verify.isEmpty(worldTimesMap)) {
-            return;
-        }
-
-        Set<String> worldNames = worldTimesMap.keySet();
-        db.getWorldTable().saveWorlds(worldNames);
-
-        executeBatch(new ExecStatement(insertStatement) {
-            @Override
-            public void prepare(PreparedStatement statement) throws SQLException {
-                for (Map.Entry<String, GMTimes> entry : worldTimesMap.entrySet()) {
-                    String worldName = entry.getKey();
-                    GMTimes gmTimes = entry.getValue();
-                    statement.setString(1, uuid.toString());
-                    statement.setString(2, worldName);
-                    String serverUUID = getServerUUID().toString();
-                    statement.setString(3, serverUUID);
-                    statement.setString(4, serverUUID);
-                    statement.setInt(5, sessionID);
-
-                    String[] gms = GMTimes.getGMKeyArray();
-                    statement.setLong(6, gmTimes.getTime(gms[0]));
-                    statement.setLong(7, gmTimes.getTime(gms[1]));
-                    statement.setLong(8, gmTimes.getTime(gms[2]));
-                    statement.setLong(9, gmTimes.getTime(gms[3]));
-                    statement.addBatch();
-                }
-            }
-        });
-    }
-
     public WorldTimes getWorldTimesOfUser(UUID uuid) {
-        String worldIDColumn = worldTable + "." + WorldTable.ID;
+        String worldIDColumn = WorldTable.TABLE_NAME + "." + WorldTable.ID;
-        String worldNameColumn = worldTable + "." + WorldTable.NAME + " as world_name";
+        String worldNameColumn = WorldTable.TABLE_NAME + "." + WorldTable.NAME + " as world_name";
         String sql = "SELECT " +
                 "SUM(" + SURVIVAL + ") as survival, " +
                 "SUM(" + CREATIVE + ") as creative, " +
                 "SUM(" + ADVENTURE + ") as adventure, " +
                 "SUM(" + SPECTATOR + ") as spectator, " +
                 worldNameColumn +
-                " FROM " + tableName +
+                " FROM " + TABLE_NAME +
-                " INNER JOIN " + worldTable + " on " + worldIDColumn + "=" + WORLD_ID +
+                " INNER JOIN " + WorldTable.TABLE_NAME + " on " + worldIDColumn + "=" + WORLD_ID +
                 " WHERE " + USER_UUID + "=?" +
                 " GROUP BY " + WORLD_ID;
 
@@ -227,8 +216,8 @@ public class WorldTimesTable extends Table {
     }
 
     public Map<Integer, WorldTimes> getAllWorldTimesBySessionID() {
-        String worldIDColumn = worldTable + "." + WorldTable.ID;
+        String worldIDColumn = WorldTable.TABLE_NAME + "." + WorldTable.ID;
-        String worldNameColumn = worldTable + "." + WorldTable.NAME + " as world_name";
+        String worldNameColumn = WorldTable.TABLE_NAME + "." + WorldTable.NAME + " as world_name";
         String sql = "SELECT " +
                 SESSION_ID + ", " +
                 SURVIVAL + ", " +
@@ -236,8 +225,8 @@ public class WorldTimesTable extends Table {
                 ADVENTURE + ", " +
                 SPECTATOR + ", " +
                 worldNameColumn +
-                " FROM " + tableName +
+                " FROM " + TABLE_NAME +
-                " INNER JOIN " + worldTable + " on " + worldIDColumn + "=" + WORLD_ID;
+                " INNER JOIN " + WorldTable.TABLE_NAME + " on " + worldIDColumn + "=" + WORLD_ID;
 
         return query(new QueryAllStatement<Map<Integer, WorldTimes>>(sql, 50000) {
             @Override
@@ -285,16 +274,11 @@ public class WorldTimesTable extends Table {
     public boolean equals(Object o) {
         if (this == o) return true;
         if (!(o instanceof WorldTimesTable)) return false;
-        if (!super.equals(o)) return false;
+        return super.equals(o);
-        WorldTimesTable that = (WorldTimesTable) o;
-        return Objects.equals(worldTable, that.worldTable) &&
-                Objects.equals(sessionsTable, that.sessionsTable) &&
-                Objects.equals(insertStatement, that.insertStatement);
     }
 
     @Override
     public int hashCode() {
-        return Objects.hash(super.hashCode(), worldTable, sessionsTable, insertStatement);
+        return Objects.hash(super.hashCode());
     }
-
 }

Plan/common/src/main/java/com/djrapitops/plan/system/cache/ProxyDataCache.java

@@ -16,11 +16,13 @@
  */
 package com.djrapitops.plan.system.cache;
 
+import com.djrapitops.plan.data.container.Session;
 import com.djrapitops.plan.system.database.DBSystem;
 import com.djrapitops.plugin.logging.error.ErrorHandler;
 
 import javax.inject.Inject;
 import javax.inject.Singleton;
+import java.util.Optional;
 import java.util.UUID;
 
 /**
@@ -39,8 +41,9 @@ public class ProxyDataCache extends DataCache {
     }
 
     @Override
-    public void endSession(UUID uuid, long time) {
+    public Optional<Session> endSession(UUID uuid, long time) {
         removeSessionFromCache(uuid);
         /* Proxy should not save sessions so session is not removed.. */
+        return Optional.empty();
     }
 }

Plan/common/src/main/java/com/djrapitops/plan/system/cache/SessionCache.java

@@ -78,18 +78,17 @@ public class SessionCache {
      * @param time Time the session ended.
      * @throws com.djrapitops.plan.api.exceptions.database.DBOpException If saving failed.
      */
-    public void endSession(UUID uuid, long time) {
+    public Optional<Session> endSession(UUID uuid, long time) {
         Session session = activeSessions.get(uuid);
-        if (session == null) {
+        if (session == null || session.getUnsafe(SessionKeys.START) > time) {
-            return;
+            return Optional.empty();
-        }
-        if (session.getUnsafe(SessionKeys.START) > time) {
-            return;
         }
         try {
             session.endSession(time);
             // Might throw a DBOpException
+            // TODO Refactor to use Event transactions when available.
             dbSystem.getDatabase().save().session(uuid, session);
+            return Optional.of(session);
         } finally {
             removeSessionFromCache(uuid);
         }

Plan/common/src/main/java/com/djrapitops/plan/system/database/databases/sql/operation/SQLSaveOps.java

@@ -21,6 +21,7 @@ import com.djrapitops.plan.data.container.*;
 import com.djrapitops.plan.data.store.objects.Nickname;
 import com.djrapitops.plan.db.SQLDB;
 import com.djrapitops.plan.db.access.transactions.Transaction;
+import com.djrapitops.plan.db.sql.queries.DataStoreQueries;
 import com.djrapitops.plan.db.sql.queries.LargeStoreQueries;
 import com.djrapitops.plan.system.database.databases.operation.SaveOperations;
 import com.djrapitops.plan.system.info.server.Server;
@@ -173,7 +174,12 @@ public class SQLSaveOps extends SQLOps implements SaveOperations {
 
     @Override
     public void session(UUID uuid, Session session) {
-        sessionsTable.saveSession(uuid, session);
+        db.executeTransaction(new Transaction() {
+            @Override
+            protected void performOperations() {
+                execute(DataStoreQueries.storeSession(session));
+            }
+        });
     }
 
     @Override

Plan/common/src/test/java/com/djrapitops/plan/db/CommonDBTest.java

@@ -28,14 +28,12 @@ import com.djrapitops.plan.data.store.keys.*;
 import com.djrapitops.plan.data.store.objects.Nickname;
 import com.djrapitops.plan.data.time.GMTimes;
 import com.djrapitops.plan.data.time.WorldTimes;
+import com.djrapitops.plan.db.access.Executable;
 import com.djrapitops.plan.db.access.Query;
 import com.djrapitops.plan.db.access.transactions.*;
 import com.djrapitops.plan.db.access.transactions.events.CommandStoreTransaction;
 import com.djrapitops.plan.db.patches.Patch;
-import com.djrapitops.plan.db.sql.queries.AggregateQueries;
+import com.djrapitops.plan.db.sql.queries.*;
-import com.djrapitops.plan.db.sql.queries.LargeFetchQueries;
-import com.djrapitops.plan.db.sql.queries.LargeStoreQueries;
-import com.djrapitops.plan.db.sql.queries.OptionalFetchQueries;
 import com.djrapitops.plan.db.sql.queries.containers.ContainerFetchQueries;
 import com.djrapitops.plan.db.sql.tables.*;
 import com.djrapitops.plan.system.PlanSystem;
@@ -133,6 +131,15 @@ public abstract class CommonDBTest {
         assertEquals(serverUUID, db.getServerUUIDSupplier().get());
     }
 
+    private void execute(Executable executable) {
+        db.executeTransaction(new Transaction() {
+            @Override
+            protected void performOperations() {
+                execute(executable);
+            }
+        });
+    }
+
     public void commitTest() throws DBInitException {
         db.close();
         db.init();
@@ -351,7 +358,7 @@ public abstract class CommonDBTest {
         assertEquals(expectedLength, session.getUnsafe(SessionKeys.WORLD_TIMES).getTotal());
 
         SessionsTable sessionsTable = db.getSessionsTable();
-        sessionsTable.saveSession(playerUUID, session);
+        execute(DataStoreQueries.storeSession(session));
 
         commitTest();
 
@@ -377,7 +384,7 @@ public abstract class CommonDBTest {
         session.setPlayerKills(createKills());
 
         SessionsTable sessionsTable = db.getSessionsTable();
-        sessionsTable.saveSession(playerUUID, session);
+        execute(DataStoreQueries.storeSession(session));
 
         commitTest();
 
@@ -508,7 +515,7 @@ public abstract class CommonDBTest {
         session.setWorldTimes(createWorldTimes());
         session.setPlayerKills(createKills());
 
-        sessionsTable.saveSession(playerUUID, session);
+        execute(DataStoreQueries.storeSession(session));
         nicknamesTable.saveUserName(playerUUID, new Nickname("TestNick", System.currentTimeMillis(), serverUUID));
         geoInfoTable.saveGeoInfo(playerUUID, new GeoInfo("1.2.3.4", "TestLoc", 223456789L, "3"));
 
@@ -567,7 +574,7 @@ public abstract class CommonDBTest {
         session.setWorldTimes(createWorldTimes());
         session.setPlayerKills(createKills());
 
-        sessionsTable.saveSession(playerUUID, session);
+        execute(DataStoreQueries.storeSession(session));
         nicknamesTable.saveUserName(playerUUID, new Nickname("TestNick", System.currentTimeMillis(), serverUUID));
         geoInfoTable.saveGeoInfo(playerUUID, new GeoInfo("1.2.3.4", "TestLoc", 223456789L,
                 new SHA256Hash("1.2.3.4").create()));
@@ -623,7 +630,7 @@ public abstract class CommonDBTest {
         session.setPlayerKills(createKills());
 
         SessionsTable sessionsTable = db.getSessionsTable();
-        sessionsTable.saveSession(playerUUID, session);
+        execute(DataStoreQueries.storeSession(session));
 
         commitTest();
 
@@ -647,7 +654,7 @@ public abstract class CommonDBTest {
         Session session = createSession();
         List<PlayerKill> expected = createKills();
         session.setPlayerKills(expected);
-        db.getSessionsTable().saveSession(playerUUID, session);
+        execute(DataStoreQueries.storeSession(session));
 
         commitTest();
 
@@ -710,7 +717,7 @@ public abstract class CommonDBTest {
 
         Session session = new Session(1, playerUUID, serverUUID, 12345L, 23456L, 0, 0, 0);
         session.setWorldTimes(worldTimes);
-        db.getSessionsTable().saveSession(playerUUID, session);
+        execute(DataStoreQueries.storeSession(session));
 
         Map<Integer, Session> sessions = new HashMap<>();
         sessions.put(1, session);

Plan/common/src/test/java/com/djrapitops/plan/system/webserver/JSErrorRegressionTest.java

@@ -17,9 +17,11 @@
 package com.djrapitops.plan.system.webserver;
 
 import com.djrapitops.plan.data.container.Session;
+import com.djrapitops.plan.db.Database;
+import com.djrapitops.plan.db.access.transactions.Transaction;
+import com.djrapitops.plan.db.sql.queries.DataStoreQueries;
 import com.djrapitops.plan.system.PlanSystem;
 import com.djrapitops.plan.system.database.DBSystem;
-import com.djrapitops.plan.system.database.databases.operation.SaveOperations;
 import com.djrapitops.plan.system.settings.config.PlanConfig;
 import com.djrapitops.plan.system.settings.paths.WebserverSettings;
 import com.djrapitops.plan.system.webserver.cache.PageId;
@@ -76,12 +78,18 @@ public class JSErrorRegressionTest {
 
     private static void savePlayerData() {
         DBSystem dbSystem = bukkitSystem.getDatabaseSystem();
-        SaveOperations save = dbSystem.getDatabase().save();
+        Database database = dbSystem.getDatabase();
         UUID uuid = TestConstants.PLAYER_ONE_UUID;
-        save.registerNewUser(uuid, 1000L, "TestPlayer");
+        database.save().registerNewUser(uuid, 1000L, "TestPlayer");
         Session session = new Session(uuid, TestConstants.SERVER_UUID, 1000L, "world", "SURVIVAL");
         session.endSession(11000L);
-        save.session(uuid, session);
+        database.executeTransaction(new Transaction() {
+            @Override
+            protected void performOperations() {
+                execute(DataStoreQueries.storeSession(session));
+            }
+        });
+        // TODO Refactor to use Event transactions when available.
     }
 
     @After