Re: LOB Operation and SQL*Net Message From Client and cursor #0

From: Yong Huang <yong321_at_yahoo.com>
Date: Wed, 1 May 2013 09:30:35 -0700 (PDT)
Message-ID: <1367425835.76306.YahooMailClassic_at_web184803.mail.gq1.yahoo.com>

Hi Kevin,
Thanks for this info. We tested SecureFiles LOBs and are happy with its performance. But since our shop didn't purchase required licences (I believe it requires both Advanced Security and Advanced Compression), so far we haven't used it.

Yong Huang

• On Wed, 5/1/13, Kevin Jernigan <kevin.jernigan_at_oracle.com> wrote:

From: Kevin Jernigan <kevin.jernigan_at_oracle.com> Subject: Re: LOB Operation and SQL*Net Message From Client and cursor #0 To: yong321_at_yahoo.com
Cc: elkinsl_at_verizon.net, oracle-l_at_freelists.org Date: Wednesday, May 1, 2013, 11:23 AM              

    Yong,       

      It might be true that you should avoid LOBs for smaller-than-~4K
      character strings prior to 11g, but SecureFiles LOBs in 11g is
      designed to solve those performance issues. Have you seen similar
      issues with SecureFiles LOBs in 11g?

      

      -KJ

      

      
        


        
          
            
              Kevin Jernigan
              (650) 607-0392 (o)
            
            
              Senior Director Product Management
              (415) 710-8828 (m)
            
            
              kevin.jernigan_at_oracle.com
            
            
              Advanced Compression - ACO:
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                Advanced Row Compression

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                Advanced LOB Compression

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                RMAN Backup Compression

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                Data Pump Export Compression

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                Data Guard Redo Network Transport Compression

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      On 5/1/2013 8:43 AM, Yong Huang wrote:

    
    
      
        Doing a test, converting the column to a char compared to an SQL

statement leaving it as a LOB, it completes very quickly as all the special handling for a LOB, fetching it, etc, is no longer needed.

      
      I always tell the developers to avoid CLOB unless they know for sure the text will exceed 4000 characters. Most of them simply consider LOB to be longer varchar2, not knowing that there's quite a bit of difference between the  mechanism to handle varchar2 and that to handle LOB (which is generally less efficient, and possibly over-engineered).


      
        the front end limits the [LOB comments] field to 255 characters

      
      That's even worse in the design.

Yong Huang

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Received on Wed May 01 2013 - 18:30:35 CEST