Question about search speed

[Ivan Smahin]

On Jan 28, 2013, at 4:03 PM, jda <jda at his.com> wrote:

> 
> On Jan 28, 2013, at 8:58 AM, Ivan Smahin <ivan_smahin at paradigmasoft.com> wrote:
> 
>> 
>> On Jan 28, 2013, at 3:33 PM, jda <jda at his.com> wrote:
>> 
>>> 
>>> I have a built-in search that finds the last 20 records entered. Each record has a unique sequential number (1..N) in the field "id", and this is the query:
>>> 
>>> 
>>>   SELECT * FROM mytable WHERE id > (select max(id) - 20 from mytable)
>>> 
>>> 
>>> It works, but is very slow. With a database of ~7000 records it takes ~20 seconds.
>>> 
>>> Is there a way to optimize this (using V4.9.1, Mac OS X).
>>> 
>> 
>> 
>> Thinking more of this ...
>> Is ID field indexed?
>> Could you send me that db to test it here?
>> 
> 
> Hi,
> 
> id is a VLong, not indexed.
> 
> Would you still like the database?
> 


I wish to test it here anyway.
I'm sure that indexing improves performance a lot.
But could you show your tricks with RecIDs as well?


-- 
Best regards,
Ivan Smahin
Senior Software Engineer
Paradigma Software, Inc
Valentina - The Ultra-Fast Database
http://www.valentina-db.com