MySQL replication catch-up stats script

mysql-replication-stats.sh

#!/usr/bin/env bash

# Updated/fixed version of the script from:
# https://www.percona.com/blog/2012/08/29/heres-a-quick-way-to-foresee-if-replication-slave-is-ever-going-to-catch-up-and-when/

delay=60

echo -e "Stats will be output every ${delay}s...\n"
cmd="mysql -e 'show slave status\G' | awk '/Seconds_Behind_Master/ { print \$2 }'"
while sleep $delay; do
  eval $cmd
done | awk -v delay=$delay '
{
  passed += delay;
  if (count%10==0)
    printf("s_behind h_behind | c_sec_s   eta_h | O_c_sec_s O_eta_h\n");
  if (prev==NULL){
    prev = $1;
    start = $1;
  }
  speed = (prev-$1)/delay;
  o_speed = (start-$1)/passed
  eta_h = (speed > 0) ? sprintf("%7.1f", $1/(speed*3600)) : "Inf";
  o_eta_h = (o_speed > 0) ? sprintf("%7.1f", $1/(o_speed*3600)) : "Inf";
  printf("%8d %8.2f | %7.3f %7s | %9.3f %7s\n",
    $1, $1/3600, speed, eta_h, o_speed, o_eta_h);
  prev=$1;
  count++;
  fflush();
}'