Wednesday, October 25, 2006

Support Analyst caught asking Tom

I found this very interesting.
http://asktom.oracle.com/pls/ask/f?p=4950:8:::::F4950_P8_DISPLAYID:707586567563
Search for "We have noticed several system tables where"

Keeping that in mind, here is my question in SR# 5684375.992 on 11-AUG-06:
This SR is for information only. We have noticed several system tables where dba_tab_col_statistics reports HEIGHT BALANCED histograms where bucket_cnt > distcnt (count of distinct values). It was my understanding that a similar problem was fixed in 10.2.0.1 (dbms_stats method_opt size n generates a FREQUENCY histogram where n >= NDV). However, even more perplexing is why do we have many height balanced histogram buckets on a column with only 1 distinct value?

SQL > select ENDPOINT_NUMBER,ENDPOINT_VALUE
from dba_histograms
where table_name = 'INDPART$'
and column_name = 'TS#';

ENDPOINT_NUMBER ENDPOINT_VALUE
--------------- --------------
217 79


So, some questions?
1. in sys.hist_head$, how is bucket_cnt calculated?
2. what determines how many buckets a column gets?

Is it just me, or did my support analyst ask my question on AskTom, verbatim?

While I like Tom's cavalier attitude in general (ala "and you don't need/want to be querying hist_head$, just use the normal views like the rest of us :)"), I sure wish he answered the question.

Another interesting point: this question was posed on August 14th, the same day I got fed up with the Support Analyst and asked to switch to someone else. I liked the 2nd guy much better! You could give him awards. But that first guy… wow, he needs help.

As I said, just very interesting. I wonder how many other Support Analysts I can find on AskTom.

3 comments:

dario el aburrido said...

http://www.mail-archive.com/oracle-l@fatcity.com/msg77607.html

Well... Probably not the same guy... But funny enough.

Joel Garry said...

Was poking about the tubes wondering about a hist_head$ non-issue, and came across this. Still very entertaining. Here's the current link: http://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:707586567563#69998453952058

word: gnevangs

Charles Schultz said...

Thanks, Joel. Tom is awesome, and it is no wonder that folks continue to utilize and take advantage of his charitable and gracious knowledge.