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#
# MDEV-34836: TOI transaction on FK-referenced parent table must BF abort
# SR transaction in progress on a child table.
#
# Applied SR transaction on the child table was not BF aborted by TOI running
# on the parent table for several reasons:
# Although SR correctly collected FK-referenced keys to parent, TOI in Galera
# disregards common certification index and simply sets itself to depend on the
# latest certified write set seqno.
# Since this write set was the fragment of SR transaction, TOI was allowed to run in
# parallel with SR presuming it would BF abort the latter.
#
# At the same time, DML transactions in the server don't grab MDL locks on FK-referenced
# tables, thus parent table wasn't protected by an MDL lock from SR and it couldn't
# provoke MDL lock conflict for TOI to BF abort SR transaction.
# In InnoDB, DDL transactions grab shared MDL locks on child tables, which is not enough
# to trigger MDL conflict in Galera.
# InnoDB-level Wsrep patch didn't contain correct conflict resolution logic due to the
# fact that it was believed MDL locking should always produce conflicts correctly.
#
# The fix brings conflict resolution rules similar to MDL-level checks to InnoDB, thus
# accounting for the problematic case.
#
--source include/galera_cluster.inc
--source include/have_innodb.inc
--connection node_1
CREATE TABLE parent (id INT AUTO_INCREMENT PRIMARY KEY, v INT) ENGINE=InnoDB;
INSERT INTO parent VALUES (1, 1),(2, 2),(3, 3);
CREATE TABLE child (id INT AUTO_INCREMENT PRIMARY KEY, parent_id INT, CONSTRAINT parent_fk
FOREIGN KEY (parent_id) REFERENCES parent (id)) ENGINE=InnoDB;
--connection node_2
# Start SR transaction and make it lock both parent and child tales.
SET SESSION wsrep_trx_fragment_size = 1;
START TRANSACTION;
INSERT INTO child (parent_id) VALUES (1),(2),(3);
--connection node_1
# Sync wait for SR transaction to replicate and apply fragments, thus
# locking parent table as well.
SET SESSION wsrep_sync_wait = 15;
SELECT COUNT(*) FROM child;
# Now run TOI on the parent, which BF-aborts the SR-transaction in progress.
ALTER TABLE parent AUTO_INCREMENT = 100;
--connection node_2
# Check that SR is BF-aborted.
--error ER_LOCK_DEADLOCK
COMMIT;
# Cleanup
DROP TABLE child, parent;
--source include/galera_end.inc
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