Re: long running select min(timestamp) query
Date: Wed, 30 Jan 2008 09:12:58 -0800 (PST)
I'm afraid i don't know how to calculate what the top waits are - i've seen references to it, but nothing conclusive. That udump file i had contains MANY waits, is there a tool that will go through it and summarize?
I think i finally figured out how to get the xplan, although i'm not
sure what it tells me:
2 /*+ 3 gather_plan_statistics 4 ordered use_nl(events) index(events) 5 */ 6 min(eventdate) 7 from 8 events
22-JAN-08 08.44.55.912000 AM SQL> select * from table(dbms_xplan.display_cursor(null,null,'ALLSTATS LAST')); PLAN_TABLE_OUTPUT
SQL_ID 797v1v1tbvp6s, child number 0
select /*+ gather_plan_statistics ordered use_nl(events) inde x(events) */
min(eventdate) from events
Plan hash value: 116994577
| Id | Operation | Name | Starts | E-Rows | A-Rows | A-Time | Buffers | Reads |
| 1 | SORT AGGREGATE | | 1 | 1 | 1 |00:14:53.92 | 118K| 118K| | 2 | INDEX FULL SCAN (MIN/MAX)| EVENTS_EVENTDATE | 1 |516K|
1 |00:14:53.92 | 118K| 118K|
14 rows selected.
This indicates that there are tons of estimated rows - i'm not sure what else this really tells me... i'm still digging on the other responses, thanks for all your prolonged support! Received on Wed Jan 30 2008 - 11:12:58 CST