[Info-vax] RDB Question

[Dave Froble]

On 12/4/2018 10:16 AM, Jan-Erik Söderholm wrote:

> Note also that, even if Rdb supports record locking (has done from
> V1.0, if I'm not wrong), it also has something called "Adjustable
> record locking". So Rdb doesn't move locks down to the record level
> if it doesn't have to (row contention between users).
>
> The default is what is shown from this database dump below.
> So one single process doing a large query on its own will put
> locks at blocks of 1000 database pages at a time (to start with).

Jan-Erik, I know you didn't design and implement Rdb, so I'm not 
directing this at you.

I have to ask, why would Rdb be taking out locks for a query (if I'm 
understanding the definition of query)?  If one is going to read, but 
never write, then why lock?  While there just may be some reason to not 
read locked data, that is not normally the case.  There is great 
efficiency in skipping the locking when it is not needed.

RMS has the "read regardless" capability.  This is one example.


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