Pt-osc on mysql version 5.7

MySQL & MariaDB Percona Server for MySQL 5.7
1

Hi, I did a pt-osc for a table, as pre check I can confirm that there no triggers on table using
SELECT TRIGGER_NAME FROM INFORMATION_SCHEMA.TRIGGERS WHERE TRIGGER_SCHEMA=‘’ AND event_object_table=‘

’;

However, after executing I found the message in the end showing as
2023-07-21T23:41:44 Dropping triggers…
2023-07-21T23:41:44 Dropped triggers OK.

Is this expected even when there are no triggers on the given table?

2023-07-21T23:41:44 Creating triggers…
2023-07-21T23:41:44 Created triggers OK.
2023-07-21T23:41:44 Copying approximately 43 rows…
2023-07-21T23:41:44 Copied rows OK.
2023-07-21T23:41:44 Analyzing new table…
2023-07-21T23:41:44 Swapping tables…
2023-07-21T23:41:44 Swapped original and new tables OK.
Not dropping old table because --no-drop-old-table was specified.
2023-07-21T23:41:44 Dropping triggers…
2023-07-21T23:41:44 Dropped triggers OK.

2

Hello @virin_t,

In the pre-checks query, I hope you are obfuscating the table names and not really provided them empty:

SELECT TRIGGER_NAME FROM INFORMATION_SCHEMA.TRIGGERS WHERE TRIGGER_SCHEMA='' AND event_object_table='';

You should mention TRIGGER_SCHEMA and event_object_table values in order to get correct response.

About “dropping triggers”, they were the triggers that pt-osc had created to transfer the data from OLD table to the NEW table. You probably should read the output from the top and you will also note the “creating triggers” note.

I’d invite you to read the pt-osc documentation about the usage of triggers/how it works.

Thanks,
K

3

Thank you Kedar, that makes sense.

yeah, I did mention TRIGGER_SCHEMA and event_object_table , just did have them here.
I went neurotic and created this.