Re: Table Storage Estimates

From: Sanjay Kumar <ora_user_at_hotmail.com>
Date: Wed, 28 Feb 2001 09:57:38 -0800
Message-ID: <F001.002BFBDF.20010228094618@fatcity.com>

Thanks all for the solution. I too thought of having a 1 : 1 relationship by separating the long raw column from the table. But I believe I am not permitted to do that (Strange!!!!). Since this is a third party product, I am not suppose to change any of the design issues and also the datatype.

I believe row chaining is obvious in this situation. Also the average row length is 10M. The size of the database block size is 8.

When I queried the dba_extents to find the number of blocks that have been occupied, it showed 16620 and the number of rows are 113.

I am totally confused now. Any help greatly appreciated.

Sanjay

• Original Message ----- To: "Multiple recipients of list ORACLE-L" <ORACLE-L_at_fatcity.com> Sent: Wednesday, February 28, 2001 12:46 AM

Your estimate comes to around 1 row per block. What is the average row lenght once data is in the db ? Do you have row chaining ?

What is your block size ? Can you increase it ?

If a lot of queries do not need the long raw column you can put it in another table with a 1 to 1 relationship with the parent table.

If your planning to have 200 rows of 1 block each, I do not understand why you are adding datafiles as the data should not occupied more than 3200K if you blocksize is 16K. Increase the size of the initial datafile instead of adding new ones.

• Sanjay Kumar <ora_user_at_hotmail.com> a écrit : > Hi,
  >
  > I have a table which has a structure similar to the
  > following.
  >
  > MID NOT NULL
  > VARCHAR2(24)
  > NAME
  > VARCHAR2(512)
  > PRIORITY
  > NUMBER(38)
  > PERSISTENT
  > CHAR(1)
  > EXP_DATE
  > DATE
  > BODY
  > LONG RAW
  >
  >
  > I estimated the table storage for this table using
  > the formula given in the Oracle documentation. It
  > comes to around 1 rows per block.
  >
  > It is estimated that the number of rows for this
  > table will not exceed 200.
  >
  > My questions are
  >
  > 1. Doesnt this lead to fragmentation.?
  > 2. I have added three datafiles to this tablespace
  > as of now and it seems like this might require more
  > space!!!!!!!!. How do I effectively redesign this
  > table to avoid contention and chaining?
  >
  > 3. Moreover, initially when there were 105 rows
  > inserted, I issued a count(*) and it took about 5
  > minutes? How do I reduce the time taken to execute
  > the query?
  >
  >
  > I would highly appreciate if someone comes forward
  > to help me on this.
  >
  > I am using Oracle 8.1.6 on Solaris
  >
  > Sanjay
  >
  >
  >
  

  ---

Stephane Paquette
DBA Oracle
stephane_paquette_at_yahoo.com

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Received on Wed Feb 28 2001 - 11:57:38 CST