Hi all,
Thanks a lot for the replies. I really appreciate it.
I have found the root cause for this issue.
1. I created a new tablespace called tablespace_index pointing to '/data/tablespace' on master but I forgot to create the directory on slave.
2. Once the tablespace was created on the master, the slave could not replicate the changes over because there was not directory to create the index!
3. As such, the subsequence queries started failing.
It was a good learning experience for me. I didn't foresee this to happen.
Cheers!