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  1. #1
    Join Date
    May 2000
    Location
    Bangalore,karnataka,india
    Posts
    13

    Angry

    Hi,

    How to calculate the Database size before creating the Database. can anyone give me an example with transaction details in a table.

    Thanks in Advance

  2. #2
    Join Date
    Feb 2000
    Location
    Washington DC
    Posts
    1,843
    Howmany tables ?
    How big is each table ?(number of rows)
    How big they grow in an year ?
    Howmany users ?
    Howmany transactions ?(transaction rate)

    Basic questions to be answered first. Have these figures and read Oracle docs to come up with size of the database after adding ORACLE DATABASE ENGINE needed space like RBS,REDO,SYSTEM etc.,




    Reddy,Sam

  3. #3
    Join Date
    May 2000
    Location
    Bangalore,karnataka,india
    Posts
    13

    Thumbs up

    Hi,

    Take for Example the

    No of tables =10 with 10 fields.
    No of Records Per Day=10000
    No of Users=10

    Taking this in to consideration please give me the method of calculation.

    Bye

  4. #4
    Join Date
    Mar 2001
    Posts
    188
    Hey mukeshannamalai
    you can't say this very good, because additional information where need. You must know, every single greate of the row.
    Then you must know, rase every data row with the time.
    The best thing is that you create one database and in a half year you come again hier and give us the information. I think that you know in this time how the calculation get.
    Every body has grow up

  5. #5
    Join Date
    Jan 2001
    Posts
    126
    Hi,

    From the table V$type_size you can get the bytes required for different objects.

    You have the list of tables and its fields. Workout the average row length for each table considering the column overheads. Then consider PCTFREE & estimate the space you will have in a block and also subtract the overhead for block headers etc. Like this you can translate each table into no of blocks. Now workout the space required for RBS and TEMP based on number of users etc.

    This will give you raw DB size. You have to take into account the growth and accordingly size your tablespaces.

    Hope this helps.

    Baliga

  6. #6
    Join Date
    Feb 2001
    Posts
    44
    Hi,
    All the people who have quoted above are right.You need to have the complete Table design with you.Without the table design,you will not be able to size the database.
    I am giving you the complete picture how you can size the database.
    1.Calculate the space used per row of the table using..
    select avg(nvl(vsize(column1),0))+.....+avg(nvl(vsize(columnn),0)) avg_row_length from ;

    Space used per row=Avg_row_length+no. of columns+no. of long columns*3(size >250)+row header-------(x)

    2.Estimate the block row count
    This is DB_BLOCK_SIZE/(X) --------------------(Y)

    3.Bytes available in each bock for row data
    =DB_BLOCK_SIZE-(PCTFREE(DB_BLOCK_SIZE-(52+4(X))))------------(Z)

    NOW VALIDATE THIS EQATION FOR DIFFERENT VALUES OF PCTFREE

    Z>=X*Y
    4.Next step is determining how many blocks fit into table.
    For this determine the approximate number of row counts in a year.Let this be-------- (A)
    No. of Blocks that will be required to fit the table
    =(A)/pctfree-----B

    The size of the table will be (B*DB_BLOCK_SIZE)/1024

    You can add the size of all the tables in the ERD and get the Value of the size of the database.
    Also,you can take an approximation of 20% above this level for the size of the DB.
    Hope this helps you out
    bye


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