Monday, June 6, 2022

[SOLVED] Grepping a huge file (80GB) any way to speed it up?

Issue

 grep -i -A 5 -B 5 'db_pd.Clients'  eightygigsfile.sql

This has been running for an hour on a fairly powerful linux server which is otherwise not overloaded. Any alternative to grep? Anything about my syntax that can be improved, (egrep,fgrep better?)

The file is actually in a directory which is shared with a mount to another server but the actual diskspace is local so that shouldn't make any difference?

the grep is grabbing up to 93% CPU


Solution

Here are a few options:

1) Prefix your grep command with LC_ALL=C to use the C locale instead of UTF-8.

2) Use fgrep because you're searching for a fixed string, not a regular expression.

3) Remove the -i option, if you don't need it.

So your command becomes:

LC_ALL=C fgrep -A 5 -B 5 'db_pd.Clients' eightygigsfile.sql

It will also be faster if you copy your file to RAM disk.



Answered By - dogbane
Answer Checked By - Robin (WPSolving Admin)