PL/SQL : Efficient way to loop through a large table

I need to loop through a large table contains around 20k of rows. I tried using CURSOR and BULK COLLECT but it still takes very long time, around half to complete.

Wha开发者_如何学JAVAt is an efficient way in PL/SQL to loop through the large data set.

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normally looping through 20 k rows will be faster if you simply select them. The result can be manipulated while selecting, or you can manipulate the result in a temporary table or a table variable.