Groups > comp.lang.java.programmer > #36043

Re: Scaling java app

From	Arne Vajhøj <arne@vajhoej.dk>
Newsgroups	comp.lang.java.programmer
Subject	Re: Scaling java app
Date	2016-12-02 22:36 -0500
Organization	Aioe.org NNTP Server
Message-ID	<o1tej3$mal$1@gioia.aioe.org> (permalink)
References	(19 earlier) <o1skn9$fqi$1@jstuckle.eternal-september.org> <o1su8q$5v6$1@dont-email.me> <o1t3bk$4h3$1@jstuckle.eternal-september.org> <o1tdhg$l65$1@gioia.aioe.org> <o1te19$m62$1@jstuckle.eternal-september.org>

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On 12/2/2016 10:28 PM, Jerry Stuckle wrote:
> On 12/2/2016 10:18 PM, Arne Vajhøj wrote:
>> On 12/2/2016 7:25 PM, Jerry Stuckle wrote:
>>> On 12/2/2016 5:57 PM, Martin Gregorie wrote:
>>>> On Fri, 02 Dec 2016 15:16:08 -0500, Jerry Stuckle wrote:
>>>>> On 12/2/2016 1:33 PM, Martin Gregorie wrote:
>>>>> Yes, which is all dynamic SQL.  It also has an extra layer of code
>>>>> between the application and the database-specific libraries.  Something
>>>>> COBOL doesn't have.
>>>>>
>>>> Not necessarily: in a modern RDBMS the optimisation layer is inside the
>>>> RDBMS, so the ODBC driver may be little more than an API translator and,
>>>> in some cases a field content reformatter.
>>>
>>> Yes, and the optimization must be performed with every call (perhaps it
>>> can be cached for a connection, but that's all).
>>
>> Some databases cache across connections.
>>
>> But even for those that don't it does not matter in most cases.
>
> You're right.  It doesn't matter when you're the only thing running on a
> PC.  When you have hundreds of programs running on a mainframe, it
> matters very much.

No see below.

>> Most heavy database usage in Java uses a connection that also pools
>> prepared statements.
>
> So?  Prepared statements are not static SQL.

True. With a certain definition of static.

But it means that databases that purge execution plans when connection
is closed is not a problem, because neither the connection nor the
statement get closed.

>>>> Last but not least, if you use prepared SQL statements you guarantee
>>>> that
>>>> the statement has its optimised strategy calculated and stored when the
>>>> prepared statement is created (usually during program initialisation)
>>>> and
>>>> so the per-query overheads incurred when your queries are submitted as a
>>>> string containing SQL syntax plus the data values vanish: the prepared
>>>> query was optimised once at declaration and can be reused many times
>>>> without further optimisation. Finally, prepared statements provide
>>>> protection against SQL exploits because the prepared SQL statement only
>>>> contains place-holders for data values. This means that spurious
>>>> statement terminators and other attempts to inject injurious SQL
>>>> statements will be treated purely as data: the prepared statement may
>>>> reject the 'value strings' given to it but can't and won't try to
>>>> interpret them as SQL commands.
>>>
>>> Yes, and this has to be done with *EVERY* call.
>>
>> No. Typical execution plans get cached also with parameters.
>
> But are not stored permanently in the database, and cannot be updated on
> command.

They are typical not persisted, so they only exist for whatever number
of weeks things are kept running.

>>> Additionally, prepared statements are only one way of protecting against
>>> SQL exploits.  Proper handling of the data will do it, even without
>>> prepared statements.
>>
>> That usually leads to security disasters.
>
> Not when you know what you're doing, it doesn't.  But it is a security
> disaster for incompetent programmers.

The approach to security that developers just need to know what they are
doing does not work.

Not as long as it is people doing the development. You mandate the
use of prepared statements / parameters and you use tools to verify.

>>>> I don't think you understand ODBC or have looked at the list of
>>>> supported
>>>> databases. ODBC and JDBC (which can also use ODBC DB drivers) support
>>>> almost any database you're likely to use as well as a selection of 4GL
>>>> filing systems and indexed files - if anybody has written and
>>>> published a
>>>> driver for the DB or filing system it is supported: you can download it
>>>> and its documentation and used it to access its target data store.
>>>
>>> I understand it, all right.  I've been using it since it came out in
>>> what - Windows 3.1?  Something like that, anyway.  And JDBC since early
>>> days of Java.
>>>
>>> But I've also used static SQL, and understand the difference and the
>>> advantages and disadvantages of each.  Both ODBC and JDBC add an extra
>>> layer of processing, slowing down access.
>>
>> Hmmm.
>>
>> If you really had been using them then you should know that ODBC
>> is indeed dispatching, but that JDBC is based on polymorphism, so
>> no extra layer - or maybe more correctly: not necessarily
>> an extra layer - type 2 JDBC drivers can be considered an extra
>> layer. But not so important as most database vendors have
>> type 4 JDBC drivers available today.
>
> Still another layer involved,

No. Polymorphism does not introduce an additional layer.

Arne

Thread

Scaling java app Knute Johnson <nospam@rabbitbrush.frazmtn.com> - 2016-11-21 11:06 -0600
  Re: Scaling java app Martin Gregorie <martin@address-in-sig.invalid> - 2016-11-21 19:48 +0000
    Re: Scaling java app Eric Douglas <e.d.programmer@gmail.com> - 2016-11-21 12:33 -0800
      Re: Scaling java app Knute Johnson <nospam@rabbitbrush.frazmtn.com> - 2016-11-21 18:23 -0600
        Re: Scaling java app Jerry Stuckle <jstucklex@attglobal.net> - 2016-11-21 21:22 -0500
          Re: Scaling java app Arne Vajhøj <arne@vajhoej.dk> - 2016-11-21 21:25 -0500
            Re: Scaling java app Jerry Stuckle <jstucklex@attglobal.net> - 2016-11-21 22:29 -0500
              Re: Scaling java app Arne Vajhøj <arne@vajhoej.dk> - 2016-11-21 22:41 -0500
                Re: Scaling java app Jerry Stuckle <jstucklex@attglobal.net> - 2016-11-22 10:51 -0500
          Re: Scaling java app a.laforgia@gmail.com - 2016-11-23 04:58 -0800
            Re: Scaling java app Eric Douglas <e.d.programmer@gmail.com> - 2016-11-23 05:18 -0800
              Re: Scaling java app Arne Vajhøj <arne@vajhoej.dk> - 2016-11-23 09:52 -0500
                Re: Scaling java app Eric Douglas <e.d.programmer@gmail.com> - 2016-11-23 07:51 -0800
            Re: Scaling java app Arne Vajhøj <arne@vajhoej.dk> - 2016-11-23 09:46 -0500
              Re: Scaling java app Eric Douglas <e.d.programmer@gmail.com> - 2016-11-23 08:07 -0800
                Re: Scaling java app Arne Vajhøj <arne@vajhoej.dk> - 2016-11-23 12:10 -0500
                Re: Scaling java app Eric Douglas <e.d.programmer@gmail.com> - 2016-11-23 10:39 -0800
                Re: Scaling java app Arne Vajhøj <arne@vajhoej.dk> - 2016-11-23 14:57 -0500
            Re: Scaling java app Jerry Stuckle <jstucklex@attglobal.net> - 2016-11-23 15:04 -0500
              Re: Scaling java app a.laforgia@gmail.com - 2016-11-24 02:01 -0800
                Re: Scaling java app Jerry Stuckle <jstucklex@attglobal.net> - 2016-11-24 09:10 -0500
                Re: Scaling java app a.laforgia@gmail.com - 2016-11-25 03:48 -0800
                Re: Scaling java app Jerry Stuckle <jstucklex@attglobal.net> - 2016-11-25 09:58 -0500
                Re: Scaling java app Arne Vajhøj <arne@vajhoej.dk> - 2016-11-25 10:22 -0500
              Re: Scaling java app Arne Vajhøj <arne@vajhoej.dk> - 2016-11-25 10:34 -0500
                Re: Scaling java app Jerry Stuckle <jstucklex@attglobal.net> - 2016-11-26 00:01 -0500
                Re: Scaling java app Arne Vajhøj <arne@vajhoej.dk> - 2016-11-26 09:05 -0500
                Re: Scaling java app Jerry Stuckle <jstucklex@attglobal.net> - 2016-11-26 09:52 -0500
  Re: Scaling java app Arne Vajhøj <arne@vajhoej.dk> - 2016-11-21 19:46 -0500
    Re: Scaling java app Knute Johnson <nospam@rabbitbrush.frazmtn.com> - 2016-11-21 21:12 -0600
      Re: Scaling java app Arne Vajhøj <arne@vajhoej.dk> - 2016-11-21 22:44 -0500
        Re: Scaling java app Knute Johnson <nospam@rabbitbrush.frazmtn.com> - 2016-11-22 09:56 -0600
          Re: Scaling java app Silvio <silvio@internet.com> - 2016-11-22 20:07 +0100
            Re: Scaling java app Knute Johnson <nospam@rabbitbrush.frazmtn.com> - 2016-11-22 18:00 -0600
              Re: Scaling java app Knute Johnson <nospam@rabbitbrush.frazmtn.com> - 2016-11-22 19:35 -0600
              Re: Scaling java app Silvio <silvio@internet.com> - 2016-11-24 00:51 +0100
          Re: Scaling java app Arne Vajhøj <arne@vajhoej.dk> - 2016-11-23 10:26 -0500
            Re: Scaling java app Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-11-23 15:54 -0500
              Re: Scaling java app Arne Vajhøj <arne@vajhoej.dk> - 2016-11-23 20:46 -0500
          Re: Scaling java app Arne Vajhøj <arne@vajhoej.dk> - 2016-11-23 12:00 -0500
            Re: Scaling java app Knute Johnson <nospam@rabbitbrush.frazmtn.com> - 2016-11-23 19:53 -0600
              Re: Scaling java app Arne Vajhøj <arne@vajhoej.dk> - 2016-11-23 21:21 -0500
                Re: Scaling java app Arne Vajhøj <arne@vajhoej.dk> - 2016-11-23 21:34 -0500
                Re: Scaling java app Eric Douglas <e.d.programmer@gmail.com> - 2016-11-28 05:06 -0800
                Re: Scaling java app Richard Maher <maher_rjSPAMLESS@hotmail.com> - 2016-11-24 20:45 +0800
                Re: Scaling java app Jerry Stuckle <jstucklex@attglobal.net> - 2016-11-24 09:12 -0500
                Re: Scaling java app Arne Vajhøj <arne@vajhoej.dk> - 2016-11-25 10:32 -0500
                Re: Scaling java app Jerry Stuckle <jstucklex@attglobal.net> - 2016-11-26 00:05 -0500
                Re: Scaling java app Martin Gregorie <martin@address-in-sig.invalid> - 2016-11-26 15:24 +0000
                Re: Scaling java app Eric Douglas <e.d.programmer@gmail.com> - 2016-11-28 05:08 -0800
                Re: Scaling java app Arne Vajhøj <arne@vajhoej.dk> - 2016-11-28 19:51 -0500
                Re: Scaling java app Jerry Stuckle <jstucklex@attglobal.net> - 2016-11-28 21:18 -0500
                Re: Scaling java app lewbloch@gmail.com - 2016-11-29 13:50 -0800
                Re: Scaling java app Jerry Stuckle <jstucklex@attglobal.net> - 2016-11-29 16:53 -0500
                Re: Scaling java app lewbloch@gmail.com - 2016-12-01 13:27 -0800
                Re: Scaling java app Jerry Stuckle <jstucklex@attglobal.net> - 2016-12-01 16:45 -0500
                Re: Scaling java app Arne Vajhøj <arne@vajhoej.dk> - 2016-12-01 22:07 -0500
                Re: Scaling java app Jerry Stuckle <jstucklex@attglobal.net> - 2016-12-02 10:35 -0500
                Re: Scaling java app Gene Wirchenko <genew@telus.net> - 2016-12-02 08:53 -0800
                Re: Scaling java app Jerry Stuckle <jstucklex@attglobal.net> - 2016-12-02 15:05 -0500
                Re: Scaling java app Martin Gregorie <martin@address-in-sig.invalid> - 2016-12-02 20:25 +0000
                Re: Scaling java app Jerry Stuckle <jstucklex@attglobal.net> - 2016-12-02 16:20 -0500
                Re: Scaling java app Martin Gregorie <martin@address-in-sig.invalid> - 2016-12-02 18:33 +0000
                Re: Scaling java app Jerry Stuckle <jstucklex@attglobal.net> - 2016-12-02 15:16 -0500
                Re: Scaling java app Martin Gregorie <martin@address-in-sig.invalid> - 2016-12-02 22:57 +0000
                Re: Scaling java app Jerry Stuckle <jstucklex@attglobal.net> - 2016-12-02 19:25 -0500
                Re: Scaling java app Arne Vajhøj <arne@vajhoej.dk> - 2016-12-02 22:18 -0500
                Re: Scaling java app Jerry Stuckle <jstucklex@attglobal.net> - 2016-12-02 22:28 -0500
                Re: Scaling java app Arne Vajhøj <arne@vajhoej.dk> - 2016-12-02 22:36 -0500
                Re: Scaling java app Jerry Stuckle <jstucklex@attglobal.net> - 2016-12-03 11:27 -0500
                Re: Scaling java app Arne Vajhøj <arne@vajhoej.dk> - 2016-12-02 22:05 -0500
                Re: Scaling java app Jerry Stuckle <jstucklex@attglobal.net> - 2016-12-02 22:30 -0500
                Re: Scaling java app Arne Vajhøj <arne@vajhoej.dk> - 2016-12-02 22:41 -0500
                Re: Scaling java app Jerry Stuckle <jstucklex@attglobal.net> - 2016-12-03 11:29 -0500
                Re: Scaling java app Arne Vajhøj <arne@vajhoej.dk> - 2016-12-02 22:00 -0500
                Re: Scaling java app lewbloch@gmail.com - 2016-12-02 11:40 -0800
                Re: Scaling java app Jerry Stuckle <jstucklex@attglobal.net> - 2016-12-02 15:17 -0500
                Re: Scaling java app lewbloch@gmail.com - 2016-12-02 16:26 -0800
                Re: Scaling java app Jerry Stuckle <jstucklex@attglobal.net> - 2016-12-02 20:46 -0500
                Re: Scaling java app Eric Douglas <e.d.programmer@gmail.com> - 2016-12-02 12:44 -0800
                Re: Scaling java app Arne Vajhøj <arne@vajhoej.dk> - 2016-12-02 21:57 -0500
                Re: Scaling java app Jerry Stuckle <jstucklex@attglobal.net> - 2016-12-02 22:40 -0500
                Re: Scaling java app Arne Vajhøj <arne@vajhoej.dk> - 2016-12-02 22:51 -0500
                Re: Scaling java app Jerry Stuckle <jstucklex@attglobal.net> - 2016-12-03 11:42 -0500
                Re: Scaling java app Andreas Leitgeb <avl@logic.at> - 2016-12-02 15:43 +0000
                Re: Scaling java app Arne Vajhøj <arne@vajhoej.dk> - 2016-12-02 21:19 -0500
                Re: Scaling java app Martin Gregorie <martin@address-in-sig.invalid> - 2016-12-02 10:28 +0000
                Re: Scaling java app Jerry Stuckle <jstucklex@attglobal.net> - 2016-12-02 10:37 -0500
                Re: Scaling java app Gene Wirchenko <genew@telus.net> - 2016-12-02 09:00 -0800
                Re: Scaling java app Eric Douglas <e.d.programmer@gmail.com> - 2016-12-01 13:50 -0800
                Re: Scaling java app Arne Vajhøj <arne@vajhoej.dk> - 2016-11-25 10:30 -0500
  Re: Scaling java app Roedy Green <inquiry@mindprod.com> - 2016-11-27 16:42 -0800

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