[Info-vax] The best VMS features, was: Re: openvms renaming file

[Arne Vajhøj]

On 5/28/2018 11:01 AM, Dave Froble wrote:
> On 5/28/2018 9:42 AM, Arne Vajhøj wrote:
>> On 5/28/2018 9:38 AM, Jan-Erik Söderholm wrote:
>>> I think that SQLite is a rather special "database" most often used
>>> for single application use on single user system. And that includes
>>> more or less all of the listed systems and environmens on the page
>>> referenced above. More like a .INI file with an SQL frontend. It is
>>> single-file-only and has no concurency (everything is serialized).
>>>
>>> Do include it on VMS, but it is more or less unusable for any real
>>> application use. Maybe to hold some configuration parameters or such
>>> but probably not for live application data.
>>
>> Useless replacing RDB.
>>
>> But maybe great for replacing index-sequential files.
> 
> I don't think so.  RMS indexed files allow concurrent use, using the DLM.

You are right.

SQLite will only replace let us say the low-end of index-sequential
files usage.

For the high-end usage a database server would be needed.

> The problem with RMS isn't the design, it's the implementation.  Modern 
> RDBMS systems do much of their work in memory.  RMS does the work on 
> disk.  Quite a large difference in speed, as one might expect.
> 
> Re-implement RMS in the same manner and you'd see totally different 
> performance.  Ya got to remember how old the design and implementation 
> of RMS is.  40 years ago it worked well.

In some cases SQL support is very handy.

Arne