One of the key reasons an execution plan can differ from one system to another is because the Optimizer statistics on each system are different, for example when data on a test system is not 100% in sync with real production system. To identify differences in statistics, the DBMS_STATS.DIFF_TABLE_STATS_* functions can be used to compare statistics for a table from two different sources.
In the example below, we compare the current dictionary statistics for the EMP table with the statistics for EMP in the statistics table TAB1; the SQL statement will generate a report .
SELECT report, maxdiffpct
FROM table(DBMS_STATS.DIFF_TABLE_STATS_IN_STATTAB(‘SCOTT’,’EMP’,’TAB1’ ));
Domain Indexes -- 4 : CTXRULE Index - I have earlier provided simple demonstrations of CONTEXT and CTXCAT Indexes. A CTXRULE Index can be used to build a Document Classification application. T...
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