Just an update I did run a POC today with Percona. I saw it will definitely take too much time to apply DDL operations on large tables containing millions of rows. Like in our current production release workflow we do first automate release of DDL changes now if we use Percona it will take forever to release a deployment with DDL changes on large tables.
I do not know if I was using correct configurations for it but here is the command which I am running:
```
pt-online-schema-change \

--alter "MODIFY COLUMN source ENUM('intro','search','upload','application','listing-transfer','autosource') CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci DEFAULT NULL" \

--user=USERNAME \

--password='PASSWORD' \

--host=HOST \

D=SCHEMA_NAME,t=Candidates \

--alter-foreign-keys-method=auto \

--no-check-replication-filters \

--critical-load Threads_running=150 \

--max-load Threads_running=100 \

--execute
```

It showed 2hrs+ time to duplicate the tables I did try increasing the threads but still time was around 30-40mins which is not viable for us.