On Sep 14, 2004, at 4:28 PM, Bobak, Mark wrote: > Janine, yes, for that table, do: > alter table table_name parallel (degree 1); > and also set parallel_max_servers to 0, as the other Mark suggested. I have now done both of these things, and am intrigued by the results. tkprof output with parallel query on: call count cpu elapsed disk query current rows ------- ------ -------- ---------- ---------- ---------- ---------- ---------- Parse 1 0.01 0.01 0 0 0 0 Execute 1 0.00 0.06 0 0 3 0 Fetch 2 0.01 0.12 0 73 0 1 ------- ------ -------- ---------- ---------- ---------- ---------- ---------- total 4 0.02 0.19 0 73 3 1 Misses in library cache during parse: 1 Optimizer goal: CHOOSE Parsing user id: 38 Rows Row Source Operation ------- --------------------------------------------------- 1 SORT AGGREGATE 0 SORT AGGREGATE 0 NESTED LOOPS 0 HASH JOIN 0 TABLE ACCESS BY INDEX ROWID ACS_RELS 109 INDEX RANGE SCAN (object id 26428) 0 TABLE ACCESS FULL MEMBERSHIP_RELS 0 INDEX UNIQUE SCAN (object id 26694) tkprof output with parallel query off: call count cpu elapsed disk query current rows ------- ------ -------- ---------- ---------- ---------- ---------- ---------- Parse 1 0.00 0.00 0 0 0 0 Execute 1 0.00 0.00 0 0 0 0 Fetch 2 0.16 0.16 0 657 6 1 ------- ------ -------- ---------- ---------- ---------- ---------- ---------- total 4 0.16 0.16 0 657 6 1 Misses in library cache during parse: 1 Optimizer goal: CHOOSE Parsing user id: 38 Rows Row Source Operation ------- --------------------------------------------------- 1 SORT AGGREGATE 108 NESTED LOOPS 109 HASH JOIN 108 TABLE ACCESS BY INDEX ROWID ACS_RELS 109 INDEX RANGE SCAN (object id 26428) 170140 TABLE ACCESS FULL MEMBERSHIP_RELS 108 INDEX UNIQUE SCAN (object id 26694) So the query ran marginally faster, but was less efficient in terms of how many blocks/rows it processed. While not exactly a ringing endorsement for parallel query, this surprised me. I didn't expect to see a change like this. Is this just a matter of tkprof not accurately reporting what the parallel slaves did, or is it really processing more rows with them turned off? thanks, janine -- //www.freelists.org/webpage/oracle-l