oracle - How to keep cursors in v$sql_plan alive longer -

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i'm trying analyse query execution plan in oracle database. have set

alter system set statistics_level = all;

such can compare estimated cardinalities , times actual cardinalities , times. now, i'm running statement in order display information.

select * table(dbms_xplan.display_cursor(     sql_id => '6dt9vvx9gmd1x',      cursor_child_no => 2,      format => 'allstats last'));

but keep getting message

note: cannot fetch plan sql_id: 6dt9vvx9gmd1x, child_number: 2        please verify value of sql_id , child_number;        plan no longer in cursor cache (check       v$sql_plan)

the child_number correct when query being executed. also, when run dbms_xplan.display_cursor @ same time query, actual plan. jdbc connection closes preparedstatement after execution, maybe that's why execution plan disappears v$sql_plan.

am getting wrong, or how can analyse estimated/actual values after execution?

increase shared_pool create more caching space cursors. if in 11g, capture sql plan in baselines using optimizer_capture_sql_plan_baselines. stores plans in dba_sql_plan_baselines.


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