Critical MySQL Bug Affects 8.0.38, 8.4.1, 9.0.0 – Why You Should Skip These Upgrades

At the beginning of the month MySQL announced three new releases for the third quarter: the innovative MySQL 9.0, the long‑term support (LTS) version 8.4.1, and the incremental update 8.0.38. All three were later found to contain a critical bug (Bug #36808732).

On July 11, the open‑source database service provider Percona issued an urgent warning that the latest MySQL builds suffer from a severe issue: if a server has a large number of tables (e.g., 10,000), the MySQL daemon crashes during restart.

The affected versions are:

MySQL 8.0.38

MySQL 8.4.1

MySQL 9.0.0

Community members reproduced the problem by creating more than 8,000 tables and then restarting the instance, which consistently failed to start. Some users suggested work‑arounds such as using a shared or general tablespace, but these approaches are not recommended for production.

-- 1. Shared tablespace workaround
SET GLOBAL innodb_file_per_table = 0;
CREATE TABLE test ...;

-- 2. General tablespace workaround
CREATE TABLESPACE test ADD DATAFILE 'test.ibd';
CREATE TABLE t_test1(...) TABLESPACE=test;

MySQL acknowledged the bug and, on July 23, withdrew the three problematic releases from the download archives and republished fixed versions:

MySQL 9.0.1

MySQL 8.4.2

MySQL 8.0.39

The new release notes are brief but confirm that the InnoDB restart failure when more than 8,000 tables exist (error 36808732) has been resolved, and a Group Replication CTAS bug (error 36784284) has also been fixed.

Release‑notes excerpt:

9.0.1 Release Notes
InnoDB: In certain cases, creating a large number of tables (8001 or more) prevents the server from restarting successfully. (Error #36808732)
Reference: This issue is related to Bug #33398681.
InnoDB: Improved performance of tablespace file scanning at startup. (Errors #110402, #35200385)
Group Replication: Running CREATE TABLE ... SELECT statements may cause replica errors. (Error #36784284)

The original buggy binaries (8.0.38, 8.4.1, 9.0.0) have been removed from the historical archive, and the download links now point only to the patched releases.