Ok.. Thanks Rajeev
I'll try that on my test bed
On Jun 28, 2017, at 08:10, RajeevGM <rprabha01@xxxxxxxxx> wrote:
Hi,
Like other listers have already mentioned,
you can get the compression ratio using
dbms_compression..
As regards its' effectiveness, for example
you could query against the hcc compressed table, followed by that against
v$sess* tables
and compare the numbers to that of a non hcc compressed one ...
Between the compression data captured from
dbms_compression.get_compression_ratio
and the above v$sess** tables, you should be able to determine how effective
has hcc been
in your environment.
HTH,
Rajeev
On Jun 28, 2017, at 7:45 AM, Pantheon Systems <pantheon.oracle@xxxxxxxxx>
wrote:
Let me clarify
If I hv HCC enabled right now, how do I tell how effective it is
I.e : How well it's compressing the data to a similar set of data ( the same
database ) that doesn't hv HCC-enabled
On Jun 27, 2017, at 21:06, Andy Klock <andy@xxxxxxxxxxxxxxx> wrote:
On Tue, Jun 27, 2017 at 7:50 PM, Pantheon Systems
<pantheon.oracle@xxxxxxxxx> wrote:
Folks
Is there a way to estimate HCC compression ratios?
I.e.. To what extent HCC is employed in the database ?
Or what percentage of tables are HCC compressed & their ratios & whether
it is archive high / low and so on
I'm not sure I exactly understand your question. If you don't have a means
to test actual compression, you can estimate compression ratios by sampling
your data with DBMS_COMPRESSION. How you employ it and what percentage of
the tables use HCC in your database is really up to what your needs are. If
your tables are bulk loaded and only SELECTed from then HCC may be great.
If they are heavily DMLed then probably not so great.
Andy K