Percona Monthly Bug Report: July 2021
source link: https://www.percona.com/blog/percona-monthly-bug-report-july-2021/
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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 July 2021 edition of our monthly bug report, we have the following list of bugs:
Percona Server for MySQL/MySQL Bugs
MySQL#77239: When using multi-threaded replication, SQL thread in replica stop with the following error sometimes, and further SQL Thread does not preserve this information about the error in its status and replica starts without any error.
Last_SQL_Errno: 1756
Last_SQL_Error: … The slave coordinator and worker threads are stopped, possibly leaving data in an inconsistent state. A restart should restore consistency automatically, although using non-transactional storage for data or info tables or DDL queries could lead to problems. In such cases, you have to examine your data (see the documentation for details).
There are few cases mentioned in the bug report which will trigger this error, one of the cases is when regularly stopping replication occasionally it throws 1756 error for no apparent reason, even if resuming replication works without problems later.
In my test, I’m not able to reproduce this issue with the Percona Server for MySQL.
Affects Version/s: 8.0 [Tested/Reported version 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]
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-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 to 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 a backup in non-peak hours since this issue mostly occurred when MySQL is 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, and as a 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-8004: When mongos connection terminates/interrupted could be kill -9 , timeout, network issue, etc, if at this time mongodb_exporter is trying to get DB status or databases list from mongos then it crashes at runtime with panic error.
Affects Version/s: 2.x [Tested/Reported version 2.18,2.19]
PMM-8307: Users unable to use PMM with a large number of DB servers (500+) added for monitoring due to default configuration limitations for allowed numbers of connections.
As a workaround, we can increase worker_connections on Nginx.
Affects Version/s: 2.x [Tested/Reported version 2.18.0]
Fixed version: 2.21.0
PMM-7846: Adding MongoDB instance via pmm-admin with tls option is 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-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
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.
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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.
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