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

[Jan-Erik Söderholm]

Den 2018-05-28 kl. 17:20, skrev Jan-Erik Söderholm:

Sent to soon...

> Den 2018-05-28 kl. 17:01, skrev Dave Froble:
>> 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.
> 
> Now, SQLite does proved concurency, it is just that any updates are
> serialized, since every update will request an exclusive lock on the

...database, not only on the parts of the database (down to individual
records) that actually are touched by the update.

It is of course very much up to the actuall application how
that works in real life. For a single user it doesn't matter.

>>
>> 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.
>>
>