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 June 2021 edition of our monthly bug report, we have the following list of bugs:
Percona Server for MySQL/MySQL Bugs
MySQL#83263: If multiple columns have an ON DELETE constraint set to the same foreign table in that case not all constraints are executed and this will result in data inconsistency.
Example Case: When having ON DELETE SET NULL constraint on one column and an ON DELETE CASCADE constraint on another column.
In a row where both reference columns refer to the same foreign table id the ON DELETE CASCADE operation is not executed. The row is not removed as expected. But the column with ON DELETE SET NULL constraint gets the null value as expected.
As per the latest update on bug from one of the community use issues is not reproducible anymore with 5.7.21 version. I also tested with the 5.7.33 version and don’t see this issue anymore.
Affects Version/s: 5.7 [Tested/Reported version 5.7.15]
Fixed Version: 5.7.21 as per user report and my test.
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]
PS-7485 (MySQL#102094): MySQL Crash can be seen in the following cases after running store procedures.
- Execution of a prepared statement that performed a multi-table UPDATE or DELETE was not always done correctly.
- Prepared SET statements containing subqueries in stored procedures could raise an assertion.
Affects Version/s: 8.0.22 [Tested/Reported version 8.0.22]
Fixed Version/s: 8.0.23
Percona XtraDB Cluster
PXC-3645: When using RSU as wsrep_OSU_method, there is an issue of resolving metadata locks which results in deadlock.
In earlier PXC 5.7.x, both TOI and RSU DDLs don’t wait for the MDL lock, and if there is any ongoing (or just not yet committed) transaction on the same table, it will be immediately aborted and rollback.
However, the same scenario in PXC 8.0 leads to an unexpected lock – neither the transaction gets aborted nor it is allowed to commit, while DDL is waiting on MDL lock.
Affects Version/s: 8.0 [Tested/Reported version 8.0.21]
Fixed Version/s: 8.0.23
PXC-3449: When ALTER TABLE (TOI) is executed in a 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
PXC-3631: In PXC cluster running ALTER TABLE can be stuck waiting for table metadata lock state.
The issue with this bug is that normally, in TOI mode, when ALTER TABLE comes, the master node finishes already running INSERTs first, then it finishes quickly and does not affect the performance of SELECT queries on reader nodes at all.
However, sometimes it hangs for a long time and blocks other queries. With a high number of wsrep_slave_threads, the pxc node also crashed.
Affects Version/s: 5.7 [Tested/Reported version 5.7.33]
Percona XtraBackup
PXB-2486: When using xtrabackup –encrypt and –parallel with xbcloud, it doesn’t handle broken pipe correctly.The backup will hang in an infinite loop if xbcloud fails.
Affects Version/s: 2.4 [Tested/Reported version 2.4.22]
Fixed Version/s: 2.4.22
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]
Percona Toolkit
PT-1889: Incorrect output when using pt-show-grants for users based on MySQL roles and as a result, they can not be applied back properly on MySQL server.
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-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]
PMM-7941: mongodb_exporter provides a wrong replication status value on MongoDB ReplicaSet Summary dashboard, all replication servers have got status PRIMARY. This status is provided by metric mongodb_mongod_replset_my_state.
Affects Version/s: 2.x [Tested/Reported version 2.16.0]
Fixed Version: 2.18.0
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 2.0.13]
Fixed version: 2.0.19
Percona Kubernetes Operator for Percona XtraDB Cluster
New Feature in PXC-operator 1.8.0:
K8SPXC-442: The Operator can now automatically remove old backups from S3 storage if the retention period is set
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:
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.
