Actually, each of those active lines costs substantially. This is just 1M records matching the OPs data as simply as possible:

c:\test>junk91 junk.dat
Bare loop                             ## baseline
0.322973012924194
0.358 0.078 0 0

c:\test>junk91 junk.dat               ## +400% 
Add back: regex;
1.40799999237061
1.466 0.046 0 0

c:\test>junk91 junk.dat               ## +80%
Add back: regex; first push;
1.67599987983704
1.731 0.046 0 0

c:\test>junk91 junk.dat               ## +400%
Add back: regex; first push; second push;
2.94299983978271
2.932 0.124 0 0

c:\test>junk91 junk.dat              ## +150%
Add back: regex; first push; second push; shifts
3.2759997844696
3.369 0.015 0 0

[download]

The explanation is that no matter how little time something takes, if you do it a million times, it adds up.

In the OPs case, where he must be processing somewhere in the region of 2 or 3 billion records, it adds up big.

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.

The start of some sanity?

In reply to Re^2: Faster push and shift by BrowserUk
in thread Faster push and shift by baxy77bax

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