Zero rowcount ops in tkprof (only some queries!)

Hello all,

Can't quite understand this - I have just run a 26-hour level-12 10046 trace on a slow process producing a 750M trc file. Imagine my disappointment to find that the key query I am interested in has no rowsource data - or only reports zeroes. Other queries have row totals - e.g.:

Rows Row Source Operation
------- ---------------------------------------------------

      3  SORT ORDER BY (cr=3 pr=0 pw=0 time=57 us)
      3   TABLE ACCESS CLUSTER HISTGRM$ (cr=3 pr=0 pw=0 time=37 us)
      1    INDEX UNIQUE SCAN I_OBJ#_INTCOL# (cr=2 pr=0 pw=0 time=23

but for my huge query I just get an execution plan with zeroes in the Rows column:

Rows Execution Plan
------- ---------------------------------------------------

      0  INSERT STATEMENT   MODE: ALL_ROWS
      0   VIEW
      0    SORT (ORDER BY)
      0     HASH JOIN (ANTI)
      0      NESTED LOOPS
      0       NESTED LOOPS
      0        HASH JOIN (OUTER)
      0         HASH JOIN (RIGHT ANTI)

I'd be interested in any ideas as to why this is. Also, am I correct in my assumption that the rowsource is arguably more valuable than the explain plan in that it shows what *actually* happened rather than an explain plan generated by tkprof 24 hours later - albeit likely a valid explain plan?

Cheers for any insight,
cam

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