Percona Monthly Bug Report: June 2020

Percona monthly bug Report June 2020

Percona monthly bug Report June 2020At Percona, we operate on the premise that full-transparency makes a product better. We strive to build not only 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 the June 2020 edition of our monthly bug report, we have the following list of bugs:

Percona Server for MySQL/MySQL Bugs


PS-6876(MySQL#98700): MySQL 8 Crash with MASTER_COMPRESSION_ALGORITHMS / slave_compressed_protocol
Affects Version/s: 8.0 [Tested/Reported version 8.0.18]
Fixed Version: 8.0.20

With slave_compressed_protocol option, MySQL will crash if the slave fails to connect to master and then later succeeds.


PS-6800(MySQL#98142): Uncontrollable memory allocation with TRIGGERS, PROCEDURES, and FUNCTIONS
Affects Version/s: 5.7,8.0  [Tested/Reported version 5.7.29, 8.0.19]

This is a critical bug because it will result in “Out Of Memory” for users who use routines extensively.


Affects Version/s: 8.0 [Tested/Reported version 8.0.18]
Fixed Version: 8.0.21

This is a performance regression bug for statements using SELECT DISTINCT. Introduced in 8.0.18 version and fixed in 8.0.21.  As a workaround, you can use internal_tmp_mem_storage_engine=MEMORY to avoid this bug.


PS-7083(MySQL#99800) ps_truncate_all_tables() does not work in super_read_only mode
Affects Version/s: 5.7, 8.0  [Tested/Reported version 5.7.30, 8.0.20]

This is a regression bug works fine in the previous 5.7 releases but this can be again noticed in the latest MySQL server versions i.e 5.7.30 and 8.0.20. ps_truncate_all_tables() procedure, Truncates all Performance Schema summary tables, resetting all aggregated instrumentation as a snapshot. Produces a result set indicating how many tables were truncated.


MySQL#99763: error log reports invalid (old?) table or database name
Affects Version/s: 8.0  [ Tested/Reported version 8.0.20]

For the partition table, and using XA trx, after xa prepare and restart, it will reports ‘ Invalid (old?) table or database name’ in mysql error log. This issue is not affecting existing table data or access to it, but at every mysqld startup, it will add this error in mysql error log which sometimes is curious for users. The error will disappear only after dropping the problematic table which is not the option always.


PS-7057: PS 5.7 to 8.0 upgrade failed with crash when innodb_track_changed_pages =1
Affects Version/s: 8.0 [Tested/Reported version 8.0.18]


Percona XtraDB Cluster


PXC-3248: PXC 8 crashes on startup when upgrading from 5.7
Affects Version/s: 8.0   [ Tested/Reported 8.0.18]

Source of this bug is PS-7057, where upgrade failed with a crash when innodb_track_changed_pages =1


Percona XtraBackup


PXB-2162: percona-xtrabackup-80 does not work with mysql 8.0.20
Affects Version/s:  8.0  [ Tested/Reported version 8.0.11]
Fixed Version: 8.0.12

Due to the innodb redo log format changes in MySQL 8.0.20, Xtrabackup-80 failed to take a backup. This is a critical bug since xtrabackup-8.0.11 can not be used with MySQL 8.0.20. Fixed added in the latest release of Percona XtraBackup version 8.0.12.


PXB-2127: xbcloud fails to upload with an empty database to storage.
Affects Version/s:  8.0, 2.4 [Tested/Reported version 8.0.11, 2.4.20]
Fixed Version: 8.0.13, 2.4.21

Reproducible only with storage, works fine for other supported Cloud Storages.


PXB-2178: Restoring datadir from partial backup results in an inconsistent data dictionary
Affects Version/s:  8.0  [Tested/Reported version 8.0.11

Issue evident only in Xtrabackup 8.0 due to new data dictionary implementation in MySQL 8.0 version, this issue is not reproducible with xtrabackup 2.4


Percona Toolkit


PT-1747:pt-online-schema-change rebuild_constraints and metadata locking on child table
Affects Version/s:  3.x   [Tested/Reported version 3.0.13]

Critical bug since it can cause data inconsistency in the user environment. It potentially affects who rebuilds tables with foreign keys.


PT-1853: pt-online-schema-change doesn’t handle self-referencing foreign keys properly
Affects Version/s:  3.x  [Tested/Reported version 3.2.0]

Affects who rebuild tables with a self-referencing foreign key.


Percona Monitoring and Management (PMM)


PMM-5364: Cannot Add MongoDB with configured SSL
Affects Version/s:  2.x



PMM-5915: Supervisord not restarting after a restart of PMM Server virtual appliances (OVF/AMI)
Affects Version/s:  2.x  [Tested/Reported version 2.5.0]
Fixed Version:  2.6.1

Supervisor is a client/server system that allows its users to monitor and control a number of processes on UNIX-like operating systems. All PMM server components services managed by Supervisor. The problem appears only after restarting upgraded OVF/AMI.


PMM-5365: PMM2 Client fails to send Query Analytics to Server
Affects Version/s:  2.x  [Tested/Reported version 2.2.1]
Fixed Version: 2.8.0

Binary data in slow query log breaks pmm-agent with the warning “Failed to send QanCollect request.”



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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 its 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.

by Lalit Choudhary via Percona Database Performance Blog


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