size of VVarChar fields

[Ruslan Zasukhin]

On 9/30/05 9:05 PM, "Dave Parizek" <dave at Parizek.com> wrote:

Hi Dave,

> In V4RB1.x, VVarChar fields were limited to size of 504 (chars?).

This was not limit!
This was the best minimal size.

> Now max length can be up to 65535 bytes.

In v1 you also could use up to 64K

 
> With default RB encoding (UTF-8?), how many bytes per character?

Note, V4RB convert all into UTF16, and keep on disk in UTF16.
We must yet implement storage in UTF8.

UTF8 is problematic, that different languages will use different number of
bytes per character.
 
> 2?  So VVarChar can now be substantilly larger, and could be used
> instead of VText in more cases.

Note, 

    VarChar[1022] -- means 1022 UTF16 characters.
            so on disk such string will use 2044 bytes.
 
> How to decide which to use?

Old question.
 
TEXT is the only choice if you do not know limit.

If limit is less of 64K you can use VarChar

> How does this effect speed?  Or rather, what considerations should we
> keep in mind to maximize speed or when considering the performance/
> functionality tradeoff?

I afraid give here some rules. Do benchmark for you task and data.
And see results

-- 
Best regards,

Ruslan Zasukhin
VP Engineering and New Technology
Paradigma Software, Inc

Valentina - Joining Worlds of Information
http://www.paradigmasoft.com

[I feel the need: the need for speed]