# MySQL 8.0.20 support?

**URL:** <https://forums.percona.com/t/mysql-8-0-20-support/7584>\
**Category:** Percona Server for MySQL 8.0\
**Created:** [April 28, 2020, 3:51am UTC](https://forums.percona.com/t/mysql-8-0-20-support/7584 "2020-04-28T03:51:39Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![pavelvoronov1337](https://avatars.discourse-cdn.com/v4/letter/p/85f322/32.png) [@pavelvoronov1337](https://forums.percona.com/u/pavelvoronov1337)\
**Post date:** [April 28, 2020, 3:51am UTC](https://forums.percona.com/t/mysql-8-0-20-support/7584/1 "2020-04-28T03:51:39Z")

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Hi all,&nbsp;  
we updated our MySQL servers to the latest 8.0.20 version. From change notes:&nbsp;

> > [@](#):
> >
> > To address this issue, the redo log format was modified to reduce redo log record size for modifications to undo tablespaces.

Now when we run our backup, it fails with this error:&nbsp;  
``` Using server version 8.0.20 xtrabackup: uses posix\_fadvise(). xtrabackup: cd to /var/lib/mysql xtrabackup: open files limit requested 0, set to 1024 xtrabackup: using the following InnoDB configuration: xtrabackup: innodb\_data\_home\_dir = . xtrabackup: innodb\_data\_file\_path = ibdata1:12M:autoextend xtrabackup: innodb\_log\_group\_home\_dir = ./ xtrabackup: innodb\_log\_files\_in\_group = 2 xtrabackup: innodb\_log\_file\_size = 1073741824 Number of pools: 1 Unknown redo log format (4). Please follow the instructions at http://dev.mysql.com/doc/refman/8.0/en/ upgrading-downgrading.html. xtrabackup: Error: recv\_find\_max\_checkpoint() failed.  
``` Any ideas of workaround until new version of Xtrabackup?&nbsp;

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**Author:** ![pavelvoronov1337](https://avatars.discourse-cdn.com/v4/letter/p/85f322/32.png) [@pavelvoronov1337](https://forums.percona.com/u/pavelvoronov1337)\
**Post date:** [April 28, 2020, 8:14am UTC](https://forums.percona.com/t/mysql-8-0-20-support/7584/2 "2020-04-28T08:14:55Z")

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For anyone wondering, workaround for us was:&nbsp;  
1. Downgrade read only slave server to mysql 8.0.19 (basically drop 8.0.20 and download packages from&nbsp;[https://repo.mysql.com/apt/ubuntu/pool/mysql-8.0/m/mysql-community/](https://repo.mysql.com/apt/ubuntu/pool/mysql-8.0/m/mysql-community/ "Link: https://repo.mysql.com/apt/ubuntu/pool/mysql-8.0/m/mysql-community/"));  
2. Restore the latest backup;&nbsp;  
3. Connect this one as read only replica again  
  
make backups out of this replica server

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**Author:** ![lorraine.pocklington](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/lorraine.pocklington/32/37_2.png) [@lorraine.pocklington](https://forums.percona.com/u/lorraine.pocklington)\
**Post date:** [April 28, 2020, 9:24am UTC](https://forums.percona.com/t/mysql-8-0-20-support/7584/3 "2020-04-28T09:24:46Z")

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There is a blog post here with a caution about downgrading on MySQL 8&nbsp;[MySQL 8 Minor Version Upgrades Are ONE-WAY Only - Percona Database Performance Blog](https://www.percona.com/blog/2020/01/10/mysql-8-minor-version-upgrades-are-one-way-only/)  
The next release of PXB will address this issue, but yes the redo logs in MySQL have to be dealt with for it to work.