"analyze table ... ESTIMATE statistics sample 10 percent FOR TABLE FOR ALL INDEXES for all indexed columns size 2"
Why did you go from a simple analyze to gathering histograms on all indexed columns? I question the rationale of gathering histograms of "size 2". Aside from that, I question the rationale of a blanket histogram gathering (regardless of # of buckets) on "all indexed" or "all" columns. Histograms are like medicine. In the right (i.e. sparing dose) they are a therapeutic tool. In the wrong, especially too high dose, they become poison.
At 02:04 PM 12/3/2003, you wrote:
Hello,
Oracle 8.1.7.4 on HP-UX 11i
A week ago, we replaced 'analyze table ... estimate statistics sample 10 percent' with dbms_stats.gather_schema_stats('x', estimate_percent=>10, cascade=>true, degree=>4, method_opt=>''for all indexed columns size 2')
Performace is good against partitioned tables but not for non-partitioned tables.
Saw a note in Metalink that its better to do the above with 'cascade=>false' and then do a gather_index_stats separately.
In my tests, I see that 'analyze' makes the CBO use an index while dbms_stats is making the CBO to use a FTS instead.
Have you faced any similar issues?
TIA Prakash
Wolfgang Breitling
Oracle7, 8, 8i, 9i OCP DBA
Centrex Consulting Corporation
http://www.centrexcc.com
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