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Video : Online Statistics Gathering for Bulk Loads

Today’s video gives a demonstration of Online Statistics Gathering for Bulk Loads.

This is based on this article.

DML error logging redux

I posted a nice little feature of DML error logging recently, and a comment came in mentioned that caution is needed with DML error logging because the errors are logged persistently. Hence if you ran a load multiple times, or multiple sessions were utilizing the facility, then the error logging table can quickly become a soup of data that cannot be tracked back to the code your own session was running.

By default this is true, which we can see with a trivial demo. I’ll do the same load of bad rows twice and “forget” to clear out my error table. Here’s my setup – we have a target table called TGT which has rules on nulls and integers being positive, and a source table SRC which has some data that will violate those rules when it comes to loading the data.

More chances to bulk process

I’m sure most of us have read or heard at a conference the benefits of array fetching and array binding when it comes to passing data back and forth to the database. And we’ve all seen the numerous demo scripts in PL/SQL along the lines of:

FORALL i in 1 .. n 
   INSERT ...

As such, there is a misconception out there that you are only going to be able to use bulk binding for basic DML operations. So I thought I’d share this example that came in via AskTOM recently. We got asked if there was any means of improving the performance of this row-by-row operation where the DML was a complex Text index search, with the additional complication that on a row by row basis, the DML may fail but that this was an anticipated outcome that needed to be handled and moved past. The scenario presented was as follows: