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https://github.com/neondatabase/neon.git
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257ade0688
This patch aims to:
* Unify connection & querying logic of ZenithPagerserver and Postgres.
* Mitigate changes to transaction machinery introduced in `psycopg2 >= 2.9`.
Now it's possible to acquire db connection using the corresponding
method:
```python
pg = postgres.create_start('main')
conn = pg.connect()
...
conn.close()
```
This pattern can be further improved with the help of `closing`:
```python
from contextlib import closing
pg = postgres.create_start('main')
with closing(pg.connect()) as conn:
...
```
All connections produced by this method will have autocommit
enabled by default.
64 lines
2.1 KiB
Python
64 lines
2.1 KiB
Python
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(pageserver, postgres, pg_bin, zenith_cli, base_dir):
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# Create a branch for us
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zenith_cli.run(["branch", "test_multixact", "empty"])
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pg = postgres.create_start('test_multixact')
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print("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 in parallel connections to set multixact
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nclients = 3
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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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conn.cursor().execute('select * from t1 for key share')
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connections.append(conn)
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# We should have a multixact 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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zenith_cli.run(["branch", "test_multixact_new", "test_multixact@" + lsn])
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pg_new = postgres.create_start('test_multixact_new')
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print("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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