Enterprise Manager Cloud Control 12c is mostly a better product than the 10g version we were using before. But I am getting really frustrated with the Explain Plan functionality.
A big part of my job is performance tuning and monitoring running SQL. And to do that you need a clear, quick, stable view of the query plan, along with all pertinent information, such as the total cost of the plan. in EM10g, we had that.
EM12c, though, is a huge step backwards.
1. When using the "Real Time: 15 sec refresh" function, every refresh shows the "Graphical" version of the Plan. You have to then switch to the "Tabular" version, if that's what you prefer.
2. The "Tabular" view in EM10g included a summary top line showing the total cost, total IO cost, total CPU cost, etc. This is no longer available in EM12c.
3. Previously, each node of the Plan was (if appropriate) a link back to the object referenced by that step of the plan. So if the optimizer had chosen an index lookup, you could click on the index name in the plan and go to the index definition page. Superb for deciding whether the optimizer had chosen a"good" or "bad" index. Now, in EM12c, there's no drill-down functionality in the Plan. One needs to open a separate tool to analyze table or index structures alongside the EM12c Plan page. This is a terrible step backwards.
4. Not a feature in 10g or 12c, but it would be nice to be able to set one's preferred view of the plan to "Graphical" or "Tabular" and for that view to remain, no matter what refresh setting is being used in View Data.
Unless I'm missing something obvious -- and please tell me if I am! -- Oracle have really messed up here. I'm surprised no-one else has spotted these as issues. Am I alone? Or have I really missed something in the configuration?
The ability to easily view and compare SQL Plans in EM10g was great. It should have been better in EM12c. But Oracle has made it worse. It's virtually unusable now. I have to go outside EM and use TOAD to get decent Plans now. Oracle - please re-instate the original functionality.
UPDATE: Oracle have confirmed that I'm not being dim and missing something obvious. The functionality that was there in OEM 10g and 11g has been 'designed away'! I've asked MOS to raise an enhancement request to put it back in.