Cannot set record lock (error 363)

[Ruslan Zasukhin]

on 9/19/03 5:20 PM, Florian Bogeschdorfer at fb at memedia.de wrote:

>>> So the usual way is to browse with a no lock cursor and only for
>>> modification open the read/write cursor?
>>> 
>> Even in big DBMS like Oracle, SQL Server, It is BAD idea do big selections.
>> 
>> Your queries must be as precision as possible.
>> 
>> Optimistic locks compensate a little such spread users, but still better
>> avoid big selections on remote computer.
>> 
>> Think about next mySQL have ONLY client cursor, So using e.g. MySQL you will
>> MUST do selects that return only 1-20 records. Otherwise you will wait hours
>> until all recods will be sent over network.
>> 
>> 
> What would you say is the limit in Vserver. I tried a cursor with 160000
> records, made a cursor with all records and stepped through them. No
> problem. 

What you mean with limit.
You can make server side cursor even with million of records.
This is fast because no network traffic.
Later you load to client RAM only few records step by step.

> Since the cursor is built serverside it is limited by speed and ram
> of the server computer only.

Yes.

> When Vserver builds a cursor serverside, will it load all records into cache
> or will it just keep pointers to the records and read the records when they
> are needed?

Depend on query type.

Sometimes pointers, sometimes TMP table,
in any case not in cache.

In 2.0 small queries that produce one or few records will use RAM-based
tables.

-- 
Best regards,
Ruslan Zasukhin      [ I feel the need...the need for speed ]
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e-mail: ruslan at paradigmasoft.com
web: http://www.paradigmasoft.com

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