insert /*+ append */ into tab2 select * from tab2 ???

hung_my used Ask the Experts™
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Allow the row to be loaded using DIRECT PATH (by-passing the SGA). Works since
Oracle 8 I think. You use this when you want to load large amounts of data fast.
You are entering the data from tab2 table into the same table. Since you have added the /*+ append */ hint the data is going to be loaded into the the table above the high water mark.

The high water mark is the limit within which oracle searches for free blocks in which data can be entered. If no such block is found then Oracle will add the data above the mark. In this situation the search of free blocks is avoided and therefore the insert is faster. However it is just one of the many tuning tips. The performance may or may not improve if you just use this command. The drawback is that your table will keep growing even if there is sufficient free space within it.
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It means add the data to table tab2 without creating any redo-logs , thus the insertion of data is faster as the step involved in creating the redo logs doesnt come into picture.


I want to know what is the + means here?
and what is the  /*...*/ means??

how they can be used in select statement? please give example for update /delete/modify :)
/*..... */  is used for commenting....
/*+......*/ is used for providing hints to oracle on how to execute the commands....

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