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I've a question about the merge performance in oracle. I work in the business intelligence area of a big company and its quite common to have to move millions of records one side to other.

The other day my DBA told me the following:

http://www.dba-oracle.com/t_merge_upsert_performance.htm

Take a look at this, MERGE statement cold be more elegant but it provokes big problems in performance.

I'm not an expert in this, but it doesn't make sense to me. And looking in the date of the publication of the article (December, 2008) looks like in could be out of date.

We work in Oracle 11g

Should I rewrite my procedures to avoid MERGE? Thanks!

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1  
Never, ever, read anything from that website. I won't say any more, as he's known to sue –  Phil Mar 13 at 10:40
    
sorry for my ignorance, but it has a bad reputation or something? –  Lucas Mar 13 at 10:43
2  
"Should I rewrite my procedures to avoid MERGE?" - do you have performance problems related to the merge? If no, then no. If yes, then test alternatives, and if alternatives run better, then use those. –  Mat Mar 13 at 12:18
    
Do you HAVE a performance problem that can be attributed MERGE statement? Then yes, go ahead. Do you really need a MERGE? I see developers use MERGE where all they do is UPDATE or INSERT. MERGE is more suitable when you need to do more than just insert or update etc as part of same action. Since it is more complicated than a simple insert/update there may be little impact but you can always test and verify. –  Raj Mar 18 at 13:08

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