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Oracle Advanced Compression - Automatic Data Optimization

MLallo
MLallo Member Posts: 47 Blue Ribbon
edited Mar 21, 2019 3:50AM in Advanced Compression

I need some clarification about ADO.

It's clear for me that it's an automatic compression (for example it compress data after 30 days of table "inactivity" based on policy settings) but it's not clear form me this situation:

I've a oracle 12 database with 4TB data already allocated.

If I would like to use ADO I have not space saving because I've already allocated the space. Is it correct?

For example I create a new table after enable ADO (30 days) about 100GB of data.

After 30 days if I don't modify the table ADO compress it. Right?

But in this case I don't reclaim (save) space because I've already the 100GB allocated when i create the table and for example other 50GB of new compressed table....

Regards,

Mario

Answers

  • top.gun
    top.gun Member Posts: 3,666 Gold Crown
    edited Mar 20, 2019 4:04PM

    I think page 6 of this white-paper tells you how it works:

    https://www.oracle.com/a/tech/docs/enterprise-data-architecture-twp-0119.pdf

    There are 2 policies:

    - segment (or really partition)

    - rows (which is really block)

    If the using the segment policy of 30 days, then the partition needs to be old for 30 days, and then the segment compressed, which makes the segment smaller.

    If the using the rows policy of 30 days, then the rows in the block need to be old for 30 days, and then the block compressed, which won;t make the segment smaller.

  • MLallo
    MLallo Member Posts: 47 Blue Ribbon
    edited Mar 21, 2019 3:50AM

    Thank you but it's not so clear because for example in our company we use netapp storage with directnfs and we don't use Oracle ASM.

    So I would like to understand how it works with our solution.

    For example I have a 32GB tablespace already allocated and full, after 30 days If I use segment policy mean that the tablespace allocated (not only used) space would be smaller?

    If I save 10GB with compression I'll find a tablespace from 32Gb to 22GB allocated or I nerd to move data to a smaller tablespace to save space.

    Regards,