# Collation changes to a large table

**URL:** <https://forums.percona.com/t/collation-changes-to-a-large-table/30722>\
**Category:** Percona Server for MySQL 8.0\
**Created:** [May 30, 2024, 6:44pm UTC](https://forums.percona.com/t/collation-changes-to-a-large-table/30722 "2024-05-30T18:44:26Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![mysqlcoe](https://avatars.discourse-cdn.com/v4/letter/m/eb9ed0/32.png) [@mysqlcoe](https://forums.percona.com/u/mysqlcoe)\
**Post date:** [May 30, 2024, 6:44pm UTC](https://forums.percona.com/t/collation-changes-to-a-large-table/30722/1 "2024-05-30T18:44:26Z")

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Hi,

Trying to do a collation change on a very large table ( with 5 billion rows) and resulted in mysqlb instance crash. Any advice on this get this done quickly ?

Any guidance with pt-online-schema-change ? Do we have other alternatives like mysqldump?

Thanks!

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**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:** [May 30, 2024, 8:09pm UTC](https://forums.percona.com/t/collation-changes-to-a-large-table/30722/2 "2024-05-30T20:09:17Z")

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pt-online-schema-change is a great fit for this. `mysqldump` will require the table to be completely offline, so that’s probably not helpful. The out of box defaults for pt-online-schema-change are pretty good, so I’d go with that and tweak as necessary.

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**Author:** ![mysqlcoe](https://avatars.discourse-cdn.com/v4/letter/m/eb9ed0/32.png) [@mysqlcoe](https://forums.percona.com/u/mysqlcoe)\
**Post date:** [May 30, 2024, 8:14pm UTC](https://forums.percona.com/t/collation-changes-to-a-large-table/30722/3 "2024-05-30T20:14:50Z")

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> [@matthewb](#):
>
> ’d go with that and tweak as necessary.

Thank you Matt. We are doing this in our test environment. So downtime is fine. However its always great to use Percona tools when available which can simplify things.

When you have mentioned about tweaking. Could you please elaborate by giving us examples for us to try this out?

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<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:** [May 30, 2024, 8:37pm UTC](https://forums.percona.com/t/collation-changes-to-a-large-table/30722/4 "2024-05-30T20:37:29Z")

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Go with the defaults until something doesn’t look right. 99% of the time, this will not happen and the tool will just work. There are advanced options for changing chunk time, monitoring replicas, etc

> **[Percona Toolkit Documentation](https://docs.percona.com/percona-toolkit/pt-online-schema-change.html)**
>
> Command-line tools for common MySQL database administration tasks.