btw, $HoH{$p} = {%rec} isn't same as $HoH{$p} = \%rec ?

No.

The former creates a new anonymous hash by copying the contents of %rec into it, and then stores a reference to that anonymous hash into $HoH{$p}.

The latter, just stores a reference to the existing %rec into $HoH{$p}.

As %rec is declared within the while loop, you will get an empty hash each time the loop iterates and so there is no need to copy it's contents, just take a reference.

No copying means less work, so more efficient. How much difference it makes will depend on how large the hashes are. On the evidence of the script, probably not much individually, but over many iterations it may be significant enough to be worth while.

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In reply to Re^3: need to optimize my sub routine by BrowserUk
in thread need to optimize my sub routine by convenientstore

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