Larry Elkins wrote: >I've found V$SESSION_LONGOPS to be very useful, especially if you take the >time to watch it while a pig of a query is running you can track how much >time is being spent in each part of a query. For example you might notice a >lot of time is spent in a sort merge phase, or on a full table scan, etc. > > Now, this is a neat idea that I havent thought about before. Thanks. >I have seen occasional cases where the TOTALWORK column (estimated number of >blocks for example) was off, so the estimate of time remaining was off. This >has primarily been in the case of hash and sort joins, so you end up seeing >the time remaining start going negative as the SOFAR value begins to exceed >to TOTALWORK value. That's frustrating ;-) > > I noticed that. I somehow stopped trusting that table when I saw the negative time for the first time. The next thing that I expected to see in the OPNAME column was "Being beamed up, by Scottie". >But when dealing with large complex queries it can be very helpful in >tracking how much time is being spent in the various operations -- e.g. hash >join, sort output, an fts, combinations of those, etc. > > Thanks again for this suggestion. I haven't thought of using the table for optimization purposes. I was using it for "are we there yet" questions. The answer approximately as precise as the usual "soon". -- Mladen Gogala Oracle DBA -- //www.freelists.org/webpage/oracle-l