on 09-01-2009 2:42 PM
Hi experts ,
want to know WHEN the tab modifications triggering a statistics run.
BRCONNECT manual:
"If the table has the MONITORING attribute set, BRCONNECT reads the number
of inserted, deleted, and updated rows from the DBA_TAB_MODIFICATIONS
table (this is available from Oracle 8.1 onwards)."
BRCONNECT uses the number of new rows for each table in the working set, as
derived in the previous step, to see if either of the following is true:
(1) Number of new rows is greater than or equal to number of old rows * (100
+threshold) / 100
(2) Number of new rows is less than or equal to number of old rows * 100 / (100 +
+threshold)
Is the system adding up the modifications in dba_tab_modifications like that :
"new" rows = old_rows + ( inserted - deleted )
and compared against the old rows ?
i.e.
stats_change_threshold = 20.
90000 = old recs
10000 = inserted
500 = deleted
99500 = new
let's take the formulars above (1) and (2):
(1) 99500 >= 90000 * (100 + 20) / 100 = 108000 -
> no stats calculated
(2) 99500 <= 90000 * (100 + 20) / 100 = 75000 -
> no stats calculated
90000 = old recs
20000 = inserted
500 = deleted
109500 = new
(1) 109500 >= 90000 * (100 + 20) / 100 = 108000 -
> stats calculated
What do you think ?
bye
yk
Hello,
please look at sapnote #408527. There is formula.
Regards
Stefan
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