The plan As mentioned in previous post, our example is based on the sample SH schema, with an added table FOOBAR (id number, key varchar2(30)): SELECT prod_id, key FROM products CROSS JOIN foobar WHERE prod_id in (143,144,id) and id in (1,2,3); In all reverse engineering, it's good to start with something simple and to know what we to look for. Thus we want to know what the execution plan should look like; and the more unique numbers/ids we can find, the better. It's much easier to look for a number like 0x12fa1893 than for 0x0 or 0x1. The execution plan, obtained using: SELECT * FROM TABLE(DBMS_XPLAN.DISPLAY(null,null,'ALL')); is I have added the CPU cost from the full detail of the execution plan in v$sql_plan / x$kqlfxpl. Looking at the numbers, we also have rows (1 and 2 ... not very unique), bytes (34 / 30 / 8 - not bad) and what is not shown here, we also know object ids of the index and the table: 94765 and 92749 (nice). We did not use any...
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