Re: why people delete statistics bore running statistics

From: G Quesnel <dbaguy_ott_at_yahoo.com>
Date: 23 Oct 2006 11:37:03 -0700
Message-ID: <1161628623.391602.224950@i3g2000cwc.googlegroups.com>

> Also note that this could be very bad in 10g, as the statistic
> generation could be limited to a window that is too short for the
> entire schema, so it could cause some segments to not get new stats.

>> Thanks, but do not understand what do you mean? Please elaborate.

Oracle 10g will have the "gather_stats_job" by default (when the database is created by dbua) to refresh stale statistics. This job is scheduled to execute in the "maintenance_window_group" (nightly and weekends). It uses the AUTO option to process objects with missing or stale statistics first because when the maintenance window ends, the job ends. So if at 6am Tuesday morning, there are still objects that have no statistics, then they will remain that way until the evening when the job starts over.
The point is not that statistics should never be deleted, but rather to understand how 10g will be impacted, or how your processes should be impacted by the new functionality.

hth. Received on Mon Oct 23 2006 - 13:37:03 CDT