Here 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. These posts are a central place to get information on the most noteworthy open and recently resolved bugs. 

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

Percona Server for MySQL/MySQL Bugs

PS-7866 (MySQL#104961): MySQL crashes when running a complex query with JOINS. In MySQL error log it only adds a single line as “Segmentation fault (core dumped)” and there are no further details like backtraces in MySQL error log. Further analyzing the core dump shows that something happened at CreateIteratorFromAccessPath.

Affects Version/s: 8.0 [Tested/Reported version 8.0.23, 8.0.25]

PS-7778 (MySQL#104168): The prepare statement can be failed when triggers with DEFINER are used. This is a regression bug introduce after WL#9384 implementation. Issue not reproducible in lower versions, tested with 8.0.20

Affects Version/s: 8.0 [Tested/Reported version 8.0.22, 8.0.25]

Fixed version: PS-8.0.26

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]

Percona XtraDB Cluster

PXC-3724: PXC node crashes with long semaphore, this issue occurred due to locking when writing on multiple nodes in PXC cluster. This is critical as it blocks all nodes to perform any transactions and finally crashing PXC node.

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

PXC-3729: PXC node fails with two applier threads due to conflict. In a certain combination of a table having both primary key and (multi-column) unique key, and highly concurrent write workload updating similar UK values, parallel appliers on secondary nodes may conflict with each other, causing node aborts with inconsistency state. These can be seen even when writes are going to a single writer node only. As transactions were already certified and replicated, they should never fail on the appliers.

Affects Version/s: 8.0  [Tested/Reported version 8.0.21]

PXC-3449: When ALTER TABLE (TOI) is executed in the user session, sometimes it happens that it conflicts (MDL) with high priority transaction, which causes BF-BF abort and server termination.

Affects Version/s: 8.0  [Tested/Reported version 8.0.21]

Fixed Version/s: 8.0.25

Percona XtraBackup

PXB-2375:  In some cases, xtrabackup will write the wrong binlog filename, pos, and GTID combination info in xtrabackup_binlog_info. Due to this xtrabackup might not work as expected with GTID.

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.

Workaround to avoid this bug,

•  Use binary log coordinates 
• Take backup in non-peak hours since this issue mostly occurred when MySQL under heavy write operations.

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

Percona Toolkit

PT-1889: Incorrect output when using pt-show-grants for users based on MySQL roles as result they can not be applied back properly on MySQL server. Due to this, we can not use pt-show-grants for mysql roles until this issue is fixed.

Affects Version/s:  3.2.1

PT-1747: pt-online-schema-change was bringing the database into a broken state when applying the “rebuild_constraints” foreign keys modification method if any of the child tables were blocked by the metadata lock.

Affects Version/s:  3.0.13

Fixed Version: 3.3.2

PMM  [Percona Monitoring and Management]

PMM-8421: Starting from pmm-server to 2.19.0, it will break existing external service monitoring, for internal supported services like MySQL not impacted.

Affects Version/s: 2.19.0  [Tested/Reported version 2.19]

Fixed Version:  2.22.0

PMM-7116: MongoDB ReplSet Summary Dashboard shows incorrect replset member’s state: STARTUP instead of PRIMARY.

Affects Version/s: 2.x  [Tested/Reported version 2.12,2.20]

PMM-8824:If there are custom dashboards, tagged with tags that are different from the tags used for default PMM dashboards the import-dashboard.py fails with the error. As a result upgrade to the next pmm version fails.

Affects Version/s: 2.21.0  [Tested/Reported version 2.21.0]

Fixed Version:  2.22.0

PMM-4665: Frequent error messages in pmm-agent.log for components like tokudb storage engine which are not supported by upstream MySQL. As a result, it increases the overall log file size due to these additional messages.

Affects Version/s:  2.x  [Tested/Reported version 2.13.0]

Fixed version: 2.19.0

PMM-7846:  Adding MongoDB instance via pmm-admin with tls option not working and failing with error Connection check failed: timeout (context deadline exceeded).

Affects Version/s: 2.x  [Tested/Reported version 2.13, 2.16]

Summary

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

MySQL 8.0.24 Release notes

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.