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See #7718. Fix it by renaming all `types.py` to `common_types.py`. Additionally, add an advert for using `allowed_errors.py` to test any added regex.
73 lines
3.1 KiB
Python
73 lines
3.1 KiB
Python
from fixtures.common_types import TimelineId
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from fixtures.log_helper import log
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from fixtures.neon_fixtures import NeonEnvBuilder
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from fixtures.utils import print_gc_result, query_scalar
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#
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# Test where Postgres generates a lot of WAL, and it's garbage collected away, but
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# no pages are evicted so that Postgres uses an old LSN in a GetPage request.
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# We had a bug where the page server failed to find the page version because it
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# thought it was already garbage collected away, because the LSN in the GetPage
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# request was very old and the WAL from that time was indeed already removed.
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# In reality, the LSN on a GetPage request coming from a primary server is
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# just a hint that the page hasn't been modified since that LSN, and the page
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# server should return the latest page version regardless of the LSN.
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#
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def test_old_request_lsn(neon_env_builder: NeonEnvBuilder):
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# Disable pitr, because here we want to test branch creation after GC
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neon_env_builder.pageserver_config_override = "tenant_config={pitr_interval = '0 sec'}"
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env = neon_env_builder.init_start()
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env.neon_cli.create_branch("test_old_request_lsn", "main")
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endpoint = env.endpoints.create_start("test_old_request_lsn")
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pg_conn = endpoint.connect()
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cur = pg_conn.cursor()
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# Get the timeline ID of our branch. We need it for the 'do_gc' command
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timeline = TimelineId(query_scalar(cur, "SHOW neon.timeline_id"))
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pageserver_http = env.pageserver.http_client()
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# Create table, and insert some rows. Make it big enough that it doesn't fit in
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# shared_buffers.
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cur.execute("CREATE TABLE foo (id int4 PRIMARY KEY, val int, t text)")
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cur.execute(
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"""
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INSERT INTO foo
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SELECT g, 1, 'long string to consume some space' || g
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FROM generate_series(1, 100000) g
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"""
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)
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# Verify that the table is larger than shared_buffers, so that the SELECT below
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# will cause GetPage requests.
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cur.execute(
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"""
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select setting::int * pg_size_bytes(unit) as shared_buffers, pg_relation_size('foo') as tbl_size
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from pg_settings where name = 'shared_buffers'
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"""
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)
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row = cur.fetchone()
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assert row is not None
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log.info(f"shared_buffers is {row[0]}, table size {row[1]}")
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assert int(row[0]) < int(row[1])
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cur.execute("VACUUM foo")
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# Make a lot of updates on a single row, generating a lot of WAL. Trigger
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# garbage collections so that the page server will remove old page versions.
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for _ in range(10):
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pageserver_http.timeline_checkpoint(env.initial_tenant, timeline)
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gc_result = pageserver_http.timeline_gc(env.initial_tenant, timeline, 0)
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print_gc_result(gc_result)
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for _ in range(100):
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cur.execute("UPDATE foo SET val = val + 1 WHERE id = 1;")
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# All (or at least most of) the updates should've been on the same page, so
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# that we haven't had to evict any dirty pages for a long time. Now run
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# a query that sends GetPage@LSN requests with the old LSN.
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cur.execute("SELECT COUNT(*), SUM(val) FROM foo")
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assert cur.fetchone() == (100000, 101000)
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