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From Kristian Waagan <Kristian.Waa...@Sun.COM>
Subject Re: Storing length information for CLOB on disk
Date Tue, 16 Sep 2008 07:32:39 GMT
On 08/29/08 00:29, Dag H. Wanvik wrote:
> Thanks for the overview of this issue, Kristian. I agree this looks
> like something we need to address; LOBs are much used and good
> performance here is important. 

Thanks for the feedback, Dag.

I won't have time to work on this right now, but hope to do some more 
work later. People should post their comments if they have any.

> 
> Kristian Waagan <Kristian.Waagan@Sun.COM> writes:
>> I'm bringing up b) because JDBC has methods for inserting data without
>> specifying the length. Throwing out some ideas:
>>  - obtain required information on the fly, update immediately after
>> insert is done
> 
> This seems the obvious choice; what is the downside, if any, to this
> option? 

Nothing in particular that I know about yet. As long as we make the 
number of bytes (possibly) used for length information fixed, it should 
be fine to update them after all the data has been inserted.


-- 
Kristian

> 
> Storing both lengths seems cheap enough for large LOBs; if we worry this is
> an issue for smaller LOBs, I guess we could encode the ints, so short
> lengths take little space..
> 
>>  - insert data without length information, then
>>     * update on first subsequent request
>>     * use a background task to update information
>>     * add a "maintenance routine" for updating the information


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