Percona Monthly Bug Report: February 2021

Percona Bug report Feb 2021Here at Percona, we operate on the premise that full-transparency makes a product better. We strive to build the best open-source database products, but also to help you manage any issues that arise in any of the databases that we support. And, in true open-source form, report back on any issues or bugs you might encounter along the way.

We constantly update our bug reports and monitor other boards to ensure we have the latest information, but we wanted to make it a little easier for you to keep track of the most critical ones. This monthly post is a central place to get information on the most noteworthy open and recently resolved bugs. 

In this February 2021 edition of our monthly bug report, we have the following list of bugs:

Percona Server for MySQL/MySQL Bugs

PS-7477 (MySQL#101257) : MySQL-8 Crash. Prepared statements involving stored programs could cause MySQL to crash due to heap-use-after-free memory problems.

Affects Version/s: 8.0.22  [Tested/Reported version 8.0.22]

Fixed Version/s: 8.0.23


PS-7567: When enforce_storage_engine = InnoDB is set and a minor version upgrade performed, you can no longer view system and status variables.

enforce_storage_engine option is only available in Percona Server, so the bug only applicable to Percona Server. SHOW VARIABLES and SHOW STATUS both affected due to engine change of Performance_schema tables.

Affects Version/s: 8.0.22  [Tested/Reported version 8.0.22]


MySQL#102586:  When doing a multiple-table DELETE that is anticipating a foreign key ON DELETE CASCADE, the statements work on the primary but it breaks row-based replication.

Affects Version/s: 8.0, 5.7  [Tested/Reported version 8.0.23, 5.7.33]


MySQL#102175:  When the server is under heavy write operation, binary_log_position of gitid_executed shown in PS.log_status table doesn’t match with the position of that gitd shown in the binary log file. The impact of this bug is, It could break replication when using this GTID position information to start replication. 

Affects Version/s: 8.0.22  [Tested/Reported version 8.0.22]


PS-7498(MySQL#102647): Replica sql_thread getting stuck due to MASTER_DELAY. The replication applier thread in a multi-threaded replica can randomly get stuck in the “Waiting until MASTER_DELAY seconds after master executed event” state and doesn’t apply any transaction for a long time when the replica is configured with MASTER_DELAY.

The issue happens only when parallel replication enabled (slave_parallel_workers > 1) and sql_delay is enabled on the replica. Disabling the parallel replication fixes the issue and sql_thread resumes the work as expected.

Affects Version/s: 5.7  [Tested/Reported version 5.7.32]

In Percona Server we fixed this issue and the fix will be available in the next release.


PS-7542: SELECT query which creates temporary tables could lead to “ERROR 1022 (23000): Can’t write; duplicate key in table ‘/path/tmp/#sqla882_21_2‘” error.

Workaround: Running the same SELECT query works fine after changing internal_tmp_mem_storage_engine from TempTable(default) to MEMORY.

Affects Version/s: 8.0  [Tested/Reported version 8.0.17-8, 8.0.22-13]


Have open source expertise you want to share? Submit your talk for Percona Live ONLINE 2021!

Percona XtraDB Cluster

PXC-3536: PXC Cluster data inconsistency after MDL conflict solved.

Affects Version/s: 8.0,5.7  [Tested/Reported version 8.0.21-12.1, 5.7.31-31.45.3]


PXC-3455: When binlog disabled (skip-log-bin = 1) on the PXC node it crashes when a table with composite keys queried by SHOW INDEXES. 

Affects Version/s: 8.0  [Tested/Reported version 8.0.19-10, 8.0.21-12.1]


Percona XtraBackup

PXB-2375:  In some cases, XtraBackup will write the wrong binlog filename, pos, and GTID combination info in xtrabackup_binlog_info. 

If we are using this backup with GTID position details in xtrabackup_binlog_info to create a new replica, then most likely replication will break due to incorrect GTID position.

Looks like the GTID position is not consistent with binlog file pos, they are captured differently and later printed together in xtrabackup_binlog_info  file.

Affects Version/s:  8.0 [Tested/Reported version 8.0.14]


PXB-2274: XtraBackup prepare fails with the wrong LSN message when there are DML statements running during a backup stage.

Affects Version/s: 8.0 [Tested/Reported version 8.0.22-15]

Fixed Version/s: 8.0.23 [Next release]


Percona Toolkit

PT-1914: When using pt-osc on a table that has a column with the ‘Generated’ word in the column comment then it will remove all data in some columns.

Affects Version/s:  3.0.13, 3.2.1, 3.3.0


PT-1919:  Running a pt-osc on a table that has trigger/s with alter-foreign-keys-method drop_swap mode (or auto mode which could choose drop swap) will delete some trigger/s.

Affects Version/s:  3.2.1, 3.3.0


PMM  [Percona Monitoring and Management]

PMM-4665: Frequent error messages in pmm-agent.log for components like tokudb storage engine which are not supported by upstream MySQL instance. 

Affects Version/s:  2.x  [Tested/Reported version 2.0.13]



We welcome community input and feedback on all our products. If you find a bug or would like to suggest an improvement or a feature, learn how in our post, How to Report Bugs, Improvements, New Feature Requests for Percona Products.

For the most up-to-date information, be sure to follow us on Twitter, LinkedIn, and Facebook.

Quick References:

Percona JIRA  

MySQL Bug Report

Report a Bug in a Percona Product


About Percona:

As the only provider of distributions for all three of the most popular open source databases—PostgreSQL, MySQL, and MongoDB—Percona provides expertise, software, support, and services no matter the technology.

Whether it’s enabling developers or DBAs to realize value faster with tools, advice, and guidance, or making sure applications can scale and handle peak loads, Percona is here to help.

Percona is committed to being open source and preventing vendor lock-in. Percona contributes all changes to the upstream community for possible inclusion in future product releases.

Share this post

Leave a Reply