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092a9b74d3
Newer version of mypy fixes buggy error when trying to update only boto3 stubs. However it brings new checks and starts to yell when we index into cusror.fetchone without checking for None first. So this introduces a wrapper to simplify quering for scalar values. I tried to use cursor_factory connection argument but without success. There can be a better way to do that, but this looks the simplest
93 lines
3.6 KiB
Python
93 lines
3.6 KiB
Python
import pytest
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from fixtures.log_helper import log
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from fixtures.neon_fixtures import NeonEnv
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from fixtures.utils import query_scalar
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#
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# Create read-only compute nodes, anchored at historical points in time.
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#
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# This is very similar to the 'test_branch_behind' test, but instead of
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# creating branches, creates read-only nodes.
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#
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def test_readonly_node(neon_simple_env: NeonEnv):
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env = neon_simple_env
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env.neon_cli.create_branch('test_readonly_node', 'empty')
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pgmain = env.postgres.create_start('test_readonly_node')
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log.info("postgres is running on 'test_readonly_node' branch")
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main_pg_conn = pgmain.connect()
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main_cur = main_pg_conn.cursor()
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# Create table, and insert the first 100 rows
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main_cur.execute('CREATE TABLE foo (t text)')
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main_cur.execute('''
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INSERT INTO foo
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SELECT 'long string to consume some space' || g
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FROM generate_series(1, 100) g
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''')
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main_cur.execute('SELECT pg_current_wal_insert_lsn()')
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lsn_a = query_scalar(main_cur, 'SELECT pg_current_wal_insert_lsn()')
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log.info('LSN after 100 rows: ' + lsn_a)
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# Insert some more rows. (This generates enough WAL to fill a few segments.)
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main_cur.execute('''
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INSERT INTO foo
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SELECT 'long string to consume some space' || g
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FROM generate_series(1, 200000) g
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''')
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lsn_b = query_scalar(main_cur, 'SELECT pg_current_wal_insert_lsn()')
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log.info('LSN after 200100 rows: ' + lsn_b)
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# Insert many more rows. This generates enough WAL to fill a few segments.
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main_cur.execute('''
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INSERT INTO foo
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SELECT 'long string to consume some space' || g
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FROM generate_series(1, 200000) g
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''')
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lsn_c = query_scalar(main_cur, 'SELECT pg_current_wal_insert_lsn()')
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log.info('LSN after 400100 rows: ' + lsn_c)
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# Create first read-only node at the point where only 100 rows were inserted
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pg_hundred = env.postgres.create_start(branch_name='test_readonly_node',
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node_name='test_readonly_node_hundred',
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lsn=lsn_a)
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# And another at the point where 200100 rows were inserted
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pg_more = env.postgres.create_start(branch_name='test_readonly_node',
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node_name='test_readonly_node_more',
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lsn=lsn_b)
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# On the 'hundred' node, we should see only 100 rows
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hundred_pg_conn = pg_hundred.connect()
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hundred_cur = hundred_pg_conn.cursor()
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hundred_cur.execute('SELECT count(*) FROM foo')
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assert hundred_cur.fetchone() == (100, )
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# On the 'more' node, we should see 100200 rows
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more_pg_conn = pg_more.connect()
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more_cur = more_pg_conn.cursor()
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more_cur.execute('SELECT count(*) FROM foo')
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assert more_cur.fetchone() == (200100, )
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# All the rows are visible on the main branch
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main_cur.execute('SELECT count(*) FROM foo')
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assert main_cur.fetchone() == (400100, )
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# Check creating a node at segment boundary
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pg = env.postgres.create_start(branch_name='test_readonly_node',
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node_name='test_branch_segment_boundary',
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lsn='0/3000000')
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cur = pg.connect().cursor()
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cur.execute('SELECT 1')
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assert cur.fetchone() == (1, )
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# Create node at pre-initdb lsn
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with pytest.raises(Exception, match="invalid basebackup lsn"):
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# compute node startup with invalid LSN should fail
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env.postgres.create_start(branch_name='test_readonly_node',
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node_name='test_readonly_node_preinitdb',
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lsn='0/42')
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