[VXCMD] Record Locks

[Ken Ray]

On 8/23/04 8:15 PM, "Ruslan Zasukhin" <sunshine at public.kherson.ua> wrote:

> On 8/24/04 12:09 AM, "Ken Ray" <kray at sonsothunder.com> wrote:
> 
>> I don't understand why it wouldn't be consistent data... user1 is getting
>> the current values of the records in the table at the time the query hits
>> those records, so *yes*, he will get the changed 95th record, but I don't
>> understand why that is a problem if he's just *getting* the data, and not
>> *setting* it? 
> 
> Because:
> 
> * the first and main rule of TRANSACTIONS and multi-user work say:
> 
>     User must work in multi-user environment in such way,
>     like other users not exists.
>     User must not see the work of other users.
> 
>     You can read this in any book which describe you SQL,
>     transactions, servers.
> 
> 
> * Db theory says that user1 see inconsistent data because he HAVE ASK for
> records WHERE fld1 = 200. IF user1 see in this cursor record with fld1 =
> 350, then what he should think?! He should think:
>     what a stupid DBMS! I have ask it fld1 = 200.
>     but what it give me????

I understand now... I was thinking of a SELECT * FROM <table> without a
WHERE clause - in which case I wouldn't really care the state of the records
at the beginning of the query vs. the end of the query. But I understand why
you shouldn't change SQLSelectRecords... although I still can't understand
how we're getting record locks with a combination of SQLSelect (noLocks) and
SQLSelectRecords (read only).

One thing that might help, Ruslan: is there some way that we can set the
maximum size for the log file? The reason is that the current maximum size
of the log file is only enough to see a few minutes' worth of queries (at
VerboseLevel=3) and by the time our client has called us, the relevant
portion of the log that would have shown us the query that preceded the
record lock is no longer in the log file. If we set it to VerboseLevel=2
that's better (we can see the date/time of the 363) but we can't see the
queries themselves. Any way we can set the max size of the log file?

Ken Ray
Sons of Thunder Software
Web site: http://www.sonsothunder.com/
Email: kray at sonsothunder.com