If a DML statement is executed and it returns 0 rows is there redo generated? I would think not because there is nothing to roll forward in a recovery. I need confirmation.
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If a DML statement is executed and it returns 0 rows is there redo generated? I would think not because there is nothing to roll forward in a recovery. I need confirmation.
is this an academic question? you can try this yourself easily, just turn autotrace on
I guess you can call it that - A VEEP asked this question in a meeting :) . I wasn't certain so I asked here in this forum.Quote:
Originally posted by pando
is this an academic question?
I took your advice and got my (and the VEEP's :) ) answer.
Thanks!
And the answer is...?
...and the answer is NO... it does NOT create redo (notice the redo size below)
SQL> set autotrace on
SQL> delete pallet where 1 = 2 ;
0 rows deleted.
Execution Plan
----------------------------------------------------------
0 DELETE STATEMENT Optimizer=CHOOSE (Cost=108 Card=9927 Bytes= 307737)
1 0 DELETE OF 'PALLET'
2 1 FILTER
3 2 TABLE ACCESS (FULL) OF 'PALLET' (Cost=108 Card=9927 By tes=307737)
Statistics
----------------------------------------------------------
0 recursive calls
0 db block gets
0 consistent gets
0 physical reads
0 redo size
457 bytes sent via SQL*Net to client
335 bytes received via SQL*Net from client
3 SQL*Net roundtrips to/from client
1 sorts (memory)
0 sorts (disk)
0 rows processed
SQL>