java - fatal error :sorry, 已经有太多客户端从数据库获取许多查询

Question

我有连接大小的问题...我知道问题出在哪里...我的程序负载很重，我必须从数据库中获取很多查询(这里使用的是 postgres)... hibernate 连接池大小也没有帮助我......起初这是一个稳定性问题，但是当我的数据库越来越大时，这个问题也显示得更快..这个问题有什么解决办法吗？正如控制台所说:

ERROR: FATAL: sorry, too many clients already

@SuppressWarnings("deprecation")
public class DBUtilU {
private static Session scss;
private static SessionFactory sfactory;
static {
    Configuration cfg = new Configuration();
    cfg.addAnnotatedClass(Userdetails.class);
    cfg.addAnnotatedClass(Code.class);
    cfg.addAnnotatedClass(Messages.class);
    cfg.addAnnotatedClass(Comments.class);
    cfg.configure();
    new SchemaExport(cfg);
    sfactory = cfg.buildSessionFactory();

}

public static boolean saveObject(Object object) {
    try {
        scss = sfactory.getCurrentSession();
        scss.beginTransaction();
        scss.save(object);
        scss.getTransaction().commit();
    } catch (Exception e) {
        e.printStackTrace();
        scss.getTransaction().rollback();
        return false;
    }
    return true;
}

public static boolean updateObject(Object object) {
    try {
//          scss = sfactory.getCurrentSession();
//          scss.beginTransaction();
        scss.update(object);
//          scss.getTransaction().commit();
    } catch (Exception e) {
        e.printStackTrace();
        scss.getTransaction().rollback();
        return false;
    }
    return true;
}

public static boolean removeObject(Object object) {
    try {
        scss = sfactory.getCurrentSession();
        scss.beginTransaction();
        scss.delete(object);
        scss.getTransaction().commit();
        return true;
    } catch (Exception e) {
        e.printStackTrace();
        scss.getTransaction().rollback();
    }
    return false;
}

public static Userdetails loadUser(String username, String password) {
    Userdetails userdetails;
    try {
        scss = sfactory.openSession();
        scss.beginTransaction();
        String query = "from Userdetails where username=\'" + username
                + "\' and password=\'" + password + "\'";
        Query queryResult = scss.createQuery(query);
        userdetails = (Userdetails) queryResult.list().get(0);
    } catch (Exception e) {
        e.printStackTrace();
        return null;
    }

    return userdetails;

}

        public static Userdetails loadUserForMsging(String username) {
    Userdetails userdetails;
    try {
        scss = sfactory.openSession();
        scss.beginTransaction();
        String query = "from Userdetails where username=\'" +username+"\'";
        Query queryResult = scss.createQuery(query);
        userdetails = (Userdetails) queryResult.list().get(0);
    } catch (Exception e) {
        e.printStackTrace();
        return null;
    }

    return userdetails;

}

        public static Code loadCode(String Path) {
    Code code;
    try {
        scss = sfactory.openSession();
        scss.beginTransaction();
        String query = "from Code where fileName=\'" + Path + "\'";
        Query queryResult = scss.createQuery(query);
        code = (Code) queryResult.list().get(0);
    } catch (Exception e) {
        e.printStackTrace();
        return null;
    }

    return code;

}

public static void Ratermethod(String filename,int rate) {
    Code code = null;
    try {
        scss = sfactory.openSession();
        scss.beginTransaction();
        String query = "from Code where fileName=\'" + filename + "\'";
        Query queryResult = scss.createQuery(query);
        code = (Code) queryResult.list().get(0);
    } catch (Exception e) {
        e.printStackTrace();
    }
    int nor=code.getNORaters()+1;
    int prate=code.getRating();
    int nrate = ((((nor-1)*prate)+rate)/nor);
    code.setNORaters(nor);
    code.setRating(nrate);
    DBUtilU.updateObject(code);
    scss.getTransaction().commit();

}

        public static void AddCmtmethod(String filename,String cm,String cmplacer)         {
    Code code = null;
    try {
        scss = sfactory.openSession();
        scss.beginTransaction();
        String query = "from Code where fileName=\'" + filename + "\'";
        Query queryResult = scss.createQuery(query);
        code = (Code) queryResult.list().get(0);
    } catch (Exception e) {
        e.printStackTrace();
    }

            Comments cmt =new Comments(cm,cmplacer);
            cmt.setTargetCode(code);
            DBUtilU.updateObject(code);
            DBUtilU.saveObject(cmt);
//      scss.getTransaction().commit();

}

public static boolean LogoutUser() {
    try {
                if (scss.isOpen()) {
                    scss.getTransaction().commit();
                }
    } catch (Exception e) {
        e.printStackTrace();
        scss.getTransaction().rollback();
        return false;
    }
    return true;
}

public static boolean isUser(String username,String pass) {
    Userdetails userdetails = null;
    try {
        scss = sfactory.getCurrentSession();
        scss.beginTransaction();
        String query = "from Userdetails where username=\'" + username
                + "\' and password=\'" + pass + "\'";
        Query queryResult = scss.createQuery(query);
        userdetails = (Userdetails) queryResult.list().get(0);
        if (userdetails != null)
            scss.getTransaction().commit();
            return true;
    } catch (Exception e) {
        System.err.println(e);
    }
    scss.getTransaction().commit();
    return false;
}

        public static boolean UniqueUser(String username) {
    Userdetails userdetails = null;
    try {
        scss = sfactory.getCurrentSession();
        scss.beginTransaction();
        String query = "from Userdetails where username=\'" + username +     "\'";
                    Query queryResult = scss.createQuery(query);
        userdetails = (Userdetails) queryResult.list().get(0);
        if (userdetails != null)
            scss.getTransaction().commit();
            return true;
    } catch (Exception e) {
        System.err.println(e);
    }
    scss.getTransaction().commit();
    return false;
}

public static List<String> ListOfUsers() {
    List<String> Userlist = new ArrayList<String>();
    try {
        scss = sfactory.getCurrentSession();
        scss.beginTransaction();
        String query = "select username from Userdetails";
        Query queryResult = scss.createQuery(query);
        for(Object c : queryResult.list())
            Userlist.add((String)c);
                    scss.getTransaction().commit();
    } catch (Exception e) {
        e.printStackTrace();
        return null;
    }
    return Userlist;
}

public static List<Code> searchCodeTags(String tags) {
    List<Code> codelist = new ArrayList<Code>();
    try {
        scss = sfactory.getCurrentSession();
        scss.beginTransaction();
        String query = "from Code where Tags='" + tags+"'";
        Query queryResult = scss.createQuery(query);
        for(Object c : queryResult.list())
            codelist.add((Code)c);
                    String query2 = "from Code where Tags2='" + tags+"'";
                    Query queryResult2 = scss.createQuery(query2);
                    for(Object c : queryResult2.list())
            codelist.add((Code)c);
                    scss.getTransaction().commit();
    } catch (Exception e) {
        e.printStackTrace();
        return null;
    }
    return codelist;
}

        public static List<Code> searchCodeAll(String all) {
    List<Code> codelist = new ArrayList<Code>();
    try {
        scss = sfactory.getCurrentSession();
        scss.beginTransaction();
        String query = "from Code where Tags='" + all+"'";
        Query queryResult = scss.createQuery(query);
        for(Object c : queryResult.list())
            codelist.add((Code)c);
                    String query2 = "from Code where Tags2='" + all+"'";
                    Query queryResult2 = scss.createQuery(query2);
                    for(Object c : queryResult2.list())
            codelist.add((Code)c);
                    String query3 = "from Code where CodeLang='" + all+"'";
                    Query queryResult3 = scss.createQuery(query3);
                    for(Object c : queryResult3.list())
            codelist.add((Code)c);
                    String query4 = "from Code where OwnerName='" + all+"'";
                    Query queryResult4 = scss.createQuery(query4);
                    for(Object c : queryResult4.list())
            codelist.add((Code)c);
                    scss.getTransaction().commit();
    } catch (Exception e) {
        e.printStackTrace();
        return null;
    }
    return codelist;
}
                public static List<Code> searchCodePrj(String prj) {
    List<Code> codelist = new ArrayList<Code>();
    try {
        scss = sfactory.getCurrentSession();
        scss.beginTransaction();
        String query = "from Code where PrjName='" + prj+"'";
        Query queryResult = scss.createQuery(query);
        for(Object c : queryResult.list())
            codelist.add((Code)c);
                    scss.getTransaction().commit();
    } catch (Exception e) {
        e.printStackTrace();
        return null;
    }
    return codelist;
}
            public static List<Code> searchCodeLang(String lang) {
    List<Code> codelist = new ArrayList<Code>();
    try {
        scss = sfactory.getCurrentSession();
        scss.beginTransaction();
        String query = "from Code where CodeLang='" + lang+"'";
        Query queryResult = scss.createQuery(query);
        for(Object c : queryResult.list())
            codelist.add((Code)c);
                    scss.getTransaction().commit();
    } catch (Exception e) {
        e.printStackTrace();
        return null;
    }
    return codelist;
}

        public static List<Messages> MessageLoader(String Reciever) {
    List<Messages> MSGlist = new ArrayList<Messages>();
    try {
        scss = sfactory.getCurrentSession();
        scss.beginTransaction();
                    String query = "from Messages where Reciever='" + Reciever + "'";
        Query queryResult = scss.createQuery(query);
        for(Object c : queryResult.list())
            MSGlist.add((Messages)c);
                    scss.getTransaction().commit();
    } catch (Exception e) {
        e.printStackTrace();
        return null;
    }
    return MSGlist;
            }
}

康斯洛:

Jun 22, 2013 2:41:36 PM org.hibernate.engine.jdbc.spi.SqlExceptionHelper logExceptions WARN: SQL Error: 0, SQLState: 53300 Jun 22, 2013 2:41:36 PM org.hibernate.engine.jdbc.spi.SqlExceptionHelper logExceptions ERROR: FATAL: sorry, too many clients already org.hibernate.exception.GenericJDBCException: Could not open connection at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:54) at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:125) at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:110) at org.hibernate.engine.jdbc.internal.LogicalConnectionImpl.obtainConnection(LogicalConnectionImpl.java:221) at org.hibernate.engine.jdbc.internal.LogicalConnectionImpl.getConnection(LogicalConnectionImpl.java:157) at org.hibernate.engine.transaction.internal.jdbc.JdbcTransaction.doBegin(JdbcTransaction.java:67) at org.hibernate.engine.transaction.spi.AbstractTransactionImpl.begin(AbstractTransactionImpl.java:160) at org.hibernate.internal.SessionImpl.beginTransaction(SessionImpl.java:1426)

Answer 1

当你完成它们时，你必须关闭你的 session 。我在你的代码中没有看到

session.close();

---

例如这里:

public static Code loadCode(String Path) {
    Code code;
    try {
        scss = sfactory.openSession();
        scss.beginTransaction();
        String query = "from Code where fileName=\'" + Path + "\'";
        Query queryResult = scss.createQuery(query);
        code = (Code) queryResult.list().get(0);
    } catch (Exception e) {
        e.printStackTrace();
        return null;
    }

您必须关闭 session 。所以，添加 finally block :

    finally {
        scss.close();
    }