Re: DBA FAQ 4 - DC, space maps, grants
Date: 4 Dec 92 14:37:35 +1100
Message-ID: <1992Dec4.143735.530_at_hhcs.gov.au>
Some comments on DBA FAQ #4.
In article <V0m3uB1w164w_at_cellar.org>, kml_at_cellar.org (Scott Tiger) writes:
> DBA FAQ
... much deleted ...
> Part of a sample output:
>
> PARAMETER GETS GETMISSES USAGE COUNT
> -------------------------------- ---------- ---------- ---------- ----------
> dc_column_grants 18 6 6 100
> dc_columns 575005 14571 9579 14000
> dc_constraint_defs 0 0 1 100
> dc_constraints 2 2 2 500
> dc_files 6466 53 53 64
> dc_free_extents 511 211 211 600
> dc_indexes 119282 741 784 2000
> dc_object_ids 7281 35 11 2000
> dc_objects 113726 1943 1974 3000
>
> So for the dc_objects cache, the init.ora parameter setting is 3000, 1974 of
> which are currently being used. There have been 113,726 requests against
> this cache, and all but 1,943 were hits ('gets').
>
> Note that the caches are reset as part of database startups, so systems
> which are kept up for long periods should have higher cache settings.
^^^^^^^^^^^^^^^^^^^^^
Should read "higher cache usage figures and therefore more representative of
how useful the current settings are".
WARNING: Although most DC_* values can be altered in the INIT.ORA to lower
values than the supplied defaults you should be wary about ever
reducing them below the stated default settings. I have done this
in the past and received various problems with a database. Sorry,
I can't be more specific as it was over a year ago and I haven't
made the same mistake again.
-- Bruce... pihlab_at_hhcs.gov.au "If you swallow a live frog first thing in the morning ... Nothing worse will happen to you or the frog for the rest of the day" ******************************************************************* * Bruce Pihlamae -- Database Administration * * Commonwealth Department of Health, Housing & Community Services * * Canberra, Australia (W) 06-289-7056 * ******************************************************************* * These are my own thoughts and opinions, few that I have. * *******************************************************************Received on Fri Dec 04 1992 - 04:37:35 CET