Skip to main content

Collaborate 2011 - Day 5 and Wrap Up

The last (half day) of the conference. Makes me wonder why most (if not all) of the conferences add an additional half day after throwing "the" big party. Why not make it a full day and throw the party at that night - or just end with the Wednesday night party. That will keep everyone at the show. Because these last half days are usually not very well attended anymore, which is not very kind to the speakers.
Anyway, the first session of today was Obscure Tools of the Trade for Tuning SQL. The speaker - after handing out, or throwing, candies, discussed tools that are freely available to get insight in how your SQL runs. The first was not that obscure: DBMS_XPLAN. This package can show all kinds of details on your SQL and can even show AWR reports. And if you use it with the gather_plan_statistics hint, you can also show the expected rows vs the actual rows (so your statistics may be wrong). The next one wasTrace Analyzer, a.k.a. TRCA, available via Metalin. It is like TKPROF on steroids. The main advantage is, you can provide your developers access to this information without access to the udump directory or bothering the DBA. It generates nice HTML readable and navigable output.  Another one was SQLT (SQLTXPLAIN), also available from Metalink This tool understands DB-links, while TRCA does not. It has multiple methods, like xtract, xecute etc The output is like the TRCA output, but TRCA needs SQL, this one needs trace files. TRCA gives a broader view, SQLT more detailed. The last one discussed was Oracle Active Report for Real Time SQL Monitoring. You can use this by using the dbms_sqltune (11gr2) package. It returns HTML, containing Flash or not. So it generates very nice, OEM like, output (with or without using OEM).
Then Rich Niemiec did a very nice presentation about Trends in de Database World. Did you know one Oracle Database is capable of storing all, yes all, information on the entire planet if we only had the hardware? So, that's cloud computing to the max! And another remarkable thing (I've heard before, but still): The development of Fusion Applications is the largest project in the world! The three major trends Rich discussed where Consolidation, the lower cost grid using Linux and Globalisation. Of course they all come together at the end. An nice to know : Oracle's original name was SDL.
The last (real) one of the conference was about SQL Anti Patterns. It appeared to be a MySQL focussed session, but still a lot of the common mistakes made in the MySQL world also apply to the Oracle world, like these:
1. Check if a row exists before insert. You can end up with a race condition, two people might try to do the same thing (apart from that, it is an extra database action). So instead of that, just do insert and catch the error.
2. All string columns have the same, to large, size. Might take too much space for tables and indexes and arrays. So right size your strings. Another solution for reducing your indexes: use the first x characters of a column.
3. The assumption that a select without order by returns rows in order of primary key. Not true, not in MySQL, not in Oracle. Can be true if it is an "index only" query. There is no "natural" order. So if you need a specific ordering, specify that.
4. Commit and rollback in lower level functions. These may lead to unexpected results like half transactions. Ue these only on the highest calling level - the service layer, thus in the application itself.
The last session of this Collaborate was Iron Application Throw-down. Two teams had set up a solution for creating a session planner. The most striving thing was, both uses Oracle Application Express as the preferred front-end! I wonder why....

All in all, Collaborate is for 80% an applications event. So most of the session are aimed at EBS, Peoplesoft, JDEdwards etc. The same holds for the exhibitors. There is some DBA stuff going on (around 10% I guess) and the other 10% is Development, split by regular SQL and PL/SQL and APEX. No Forms, Designer and - even more remarkable, hardly no ADF or other Fusion Middleware!  So if you are a developer, the first event I would recommend, is ODTUG's KScope - see you all there!
1 comment

Popular posts from this blog

A review of APEX World 2017 - Day 1

Last week the SS Rotterdam was the beautiful location of the largest gathering of APEX Developers worldwide. With around 380 (!) attendees a new high was set. And they came from all over the world : I spotted people from The Netherlands, Belgium, Switzerland, Austria, Croatia, Germany, Denmark, Norway, UK, Ireland and the USA. And I even might have missed one or two ….

The event started with a presentation by the “father of APEX”, Mike Hichwa, talking about "Oracle APEX Past, Present and Future”. Of course everyone is curious what the APEX future might bring: Friendly URL’s, automated testing, more JSON, concurrent APEX versions, third party Oauth 2 authentication (think Facebook, Google), APEX app diff and more, a lot more, REST capabilities. And now we have to wait for APEX 5.2 … and that might take a while! 
After this keynote, the conference split up in three tracks. After the coffee break I returned to to big theatre where Geertjan Wielenga talked about "Finally Javas…

Push changed rows to an Interactive Grid

For pushing changes from the database to the end user, the regular solution is using websockets. A change in a record is detected - using a trigger or using the CQN (Change Query Notification) feature - and a notification is send to a websocket server. That websocket server broadcasts the notification over a channel to all browsers that are tuned in to that websocket channel. Then the browser reacts to that notification, usually showing an alert or refreshing a report. This trick is described on multiple sites, just Google for "oracle apex websockets" or similar.

So back in the old days, we used that notification in the browser to refresh the (interactive) report. But along comes the Interactive Grid (IG). While he full-refresh mechanism still works for IG, an IG has also the option to refresh just one row.  So wouldn't it be awesome that just the changed row(s) get refreshed upon a change in the database, instead of the whole report? Can we do it ... yes we can!
First i…

Showing a success message after closing a modal dialog

APEX 5 comes with Modal Dialogs out of the box. Very neat. Especially for adding and changing data. And to minimise the number of time a user has to click, it could be useful to add a "Close Dialog" process after the actual data processing. When the data processing fails, the Dialog stays on top showing the error. When data processing runs fine, the Dialog is closed ... without any confirmation. And this might be scary for a shaky user.

So how can we provide the user some feedback? On Page 4 of the Sample Dialog Application you can see one solution: up on a Dialog Closed Event on the parent page it does a redirect to refresh the parent page appending the success message of the "Close Dialog" process. This has two drawbacks. First, it probably refreshes more than necessary. And second, if you're using multiple layers of dialogs (dialogs that open other dialogs) the message appears in the "parent dialog".
As an alternative you could follow these steps: 1…