# Perform Mix of queries on big tables using percona toolkit

**URL:** https://forums.percona.com/t/perform-mix-of-queries-on-big-tables-using-percona-toolkit/19137
**Category:** MySQL & MariaDB
**Tags:** mysql, percona
**Created:** [December 16, 2022, 2:32am UTC](https://forums.percona.com/t/perform-mix-of-queries-on-big-tables-using-percona-toolkit/19137 "2022-12-16T02:32:03Z")
**Posts on this page:** 3
**Page:** 1

<div class="post-metadata">

### Author: ![amahajan](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/amahajan/32/8509_2.png) [@amahajan](https://forums.percona.com/u/amahajan)
#### Post date: [December 16, 2022, 2:32am UTC](https://forums.percona.com/t/perform-mix-of-queries-on-big-tables-using-percona-toolkit/19137/1 "2022-12-16T02:32:03Z")

</div>

Hi Team, so I was recently able to use pt-online-schema-changes to make the schema level upgrades. and the process did save me a bunch of 1 time use code.

I am trying to understand if there is an option in percona : _pt-online-schema-change_ by using which, if in case a process of an upgrade fails, instead of restarting the process all over again, I can continue it from the last failed stage.

**explanation:**

- I am upgrading a table that is roughly a 390-Million rows
- the upgrade task **assume** runs for say 42% in 2 days and then it fails. (I understand there is more emphasis on the reason of upgrade vs performance, and that the process deletes/does the cleanup if it fails.

**Question**  
instead of losing the effort made in 2 days, I want to be able to restart the upgrade from the last safe stage:

- how can this be achieved using the options in the **pt-online-schema-change**  
I appreciate all the help that the team can offer in this .

@matthewb@Marcelo_Altmann

---

<div class="post-metadata">

### Author: ![Ivan\_Groenewold](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/ivan_groenewold/32/6299_2.png) [@Ivan\_Groenewold](https://forums.percona.com/u/Ivan_Groenewold)
#### Post date: [December 16, 2022, 11:54am UTC](https://forums.percona.com/t/perform-mix-of-queries-on-big-tables-using-percona-toolkit/19137/2 "2022-12-16T11:54:42Z")

</div>

Hi, unfortunately pt-osc cannot be resumed. You will need to start again if there are errors.

---

<div class="post-metadata">

### Author: ![matthewb](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/matthewb/32/34_2.png) [@matthewb](https://forums.percona.com/u/matthewb)
#### Post date: [December 16, 2022, 4:38pm UTC](https://forums.percona.com/t/perform-mix-of-queries-on-big-tables-using-percona-toolkit/19137/3 "2022-12-16T16:38:59Z")

</div>

You can’t resume a pt-osc. pt-osc is stateless. The tool has no idea which of the 390-million rows are the same between original and modified tables.