Hemant Dangi d38558f99b MDEV-36117: MDL BF-BF conflict on ALTER and UPDATE with multi-level foreign key parents ...

Issue:
Mariadb acquires additional MDL locks on UPDATE/INSERT/DELETE statements
on table with foreign keys. For example, table t1 references t2, an
UPDATE to t1 will MDL lock t2 in addition to t1.
A replica may deliver an ALTER t1 and UPDATE t2 concurrently for
applying. Then the UPDATE may acquire MDL lock for t1, followed by a
conflict when the ALTER attempts to MDL lock on t1. Causing a BF-BF
conflict.

Solution:
Additional keys for the referenced/foreign table needs to be added
to avoid potential MDL conflicts with concurrent update and DDLs.

Signed-off-by: Julius Goryavsky <julius.goryavsky@mariadb.com>

2025-05-20 20:59:10 +02:00

187 KiB

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