Question

I have a mysql table with 120 million rows and I want to write a shell script to start purging some of that useless information in that table that’s not needed. Problem is I’m super new to shell scripting.

I have a datetime column with a unix timestamp in it. I want to delete every row that’s not within the last 2 months since I’ve recently enacted a data retention policy that will allow me to only keep 2 months of certain data.

TL;DR Need to build a shell script that deletes all rows up until the last 2 months of data by using the unix timestamp in the datetime column.

UPDATE: Here’s my new shell script

#!/bin/sh

i=1
while [ "$i" -ne 0 ]
do
  i=mysql -h 127.0.0.1 -u halo_ylh -pCa5d8a88 halo_twittstats < mysqlpurge.sql
  sleep 10
done

Answer 1

Wouldn’t it be easier to just use the current_timestamp and unix_timestamp function to execute:

DELETE FROM Table1 
 WHERE datetime < unix_timestamp(current_timestamp - interval 2 month)

To run it from the shell you could put that command in a file script1.sql and run it using the mysql command line tool:

mysql db_name < script1.sql