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bcf80eaa95
The logic to compute the page number was broken, and as a result, only the first page of multixact members was updated correctly. All the rest were left as zeros. Improve test_multixact.py to generate more multixacts, to cover this case. Also fix the check that the restored PG data directory matches the original one. Previously, the test compared the 'pg_new' cluster, which is a bit silly because the test restored the 'pg_new' cluster only a few lines earlier, so if the multixact WAL redo is somehow broken, the comparison will just compare two broken data directories and report success. Change it to compare the original datadir, the one where the multixacts were originally created, with a restored image of the same.
80 lines
2.8 KiB
Python
80 lines
2.8 KiB
Python
from fixtures.zenith_fixtures import ZenithEnv, check_restored_datadir_content
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from fixtures.log_helper import log
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pytest_plugins = ("fixtures.zenith_fixtures")
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#
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# Test multixact state after branching
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# Now this test is very minimalistic -
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# it only checks next_multixact_id field in restored pg_control,
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# since we don't have functions to check multixact internals.
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#
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def test_multixact(zenith_simple_env: ZenithEnv, test_output_dir):
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env = zenith_simple_env
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# Create a branch for us
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env.zenith_cli(["branch", "test_multixact", "empty"])
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pg = env.postgres.create_start('test_multixact')
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log.info("postgres is running on 'test_multixact' branch")
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pg_conn = pg.connect()
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cur = pg_conn.cursor()
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cur.execute('''
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CREATE TABLE t1(i int primary key);
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INSERT INTO t1 select * from generate_series(1, 100);
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''')
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cur.execute('SELECT next_multixact_id FROM pg_control_checkpoint()')
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next_multixact_id_old = cur.fetchone()[0]
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# Lock entries using parallel connections in a round-robin fashion.
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nclients = 20
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connections = []
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for i in range(nclients):
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# Do not turn on autocommit. We want to hold the key-share locks.
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conn = pg.connect(autocommit=False)
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connections.append(conn)
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# On each iteration, we commit the previous transaction on a connection,
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# and issue antoher select. Each SELECT generates a new multixact that
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# includes the new XID, and the XIDs of all the other parallel transactions.
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# This generates enough traffic on both multixact offsets and members SLRUs
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# to cross page boundaries.
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for i in range(5000):
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conn = connections[i % nclients]
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conn.commit()
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conn.cursor().execute('select * from t1 for key share')
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# We have multixacts now. We can close the connections.
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for c in connections:
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c.close()
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# force wal flush
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cur.execute('checkpoint')
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cur.execute('SELECT next_multixact_id, pg_current_wal_flush_lsn() FROM pg_control_checkpoint()')
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res = cur.fetchone()
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next_multixact_id = res[0]
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lsn = res[1]
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# Ensure that we did lock some tuples
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assert int(next_multixact_id) > int(next_multixact_id_old)
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# Branch at this point
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env.zenith_cli(["branch", "test_multixact_new", "test_multixact@" + lsn])
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pg_new = env.postgres.create_start('test_multixact_new')
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log.info("postgres is running on 'test_multixact_new' branch")
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pg_new_conn = pg_new.connect()
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cur_new = pg_new_conn.cursor()
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cur_new.execute('SELECT next_multixact_id FROM pg_control_checkpoint()')
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next_multixact_id_new = cur_new.fetchone()[0]
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# Check that we restored pg_controlfile correctly
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assert next_multixact_id_new == next_multixact_id
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# Check that we can restore the content of the datadir correctly
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check_restored_datadir_content(test_output_dir, env, pg)
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