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70 lines
2.8 KiB
Python
70 lines
2.8 KiB
Python
from datetime import timedelta
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from fixtures.log_helper import log
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from fixtures.neon_fixtures import NeonEnvBuilder, wait_for_last_flush_lsn
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from fixtures.utils import query_scalar
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#
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# Test pageserver get_lsn_by_timestamp API
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#
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def test_lsn_mapping(neon_env_builder: NeonEnvBuilder):
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env = neon_env_builder.init_start()
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new_timeline_id = env.neon_cli.create_branch("test_lsn_mapping")
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pgmain = env.postgres.create_start("test_lsn_mapping")
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log.info("postgres is running on 'test_lsn_mapping' branch")
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cur = pgmain.connect().cursor()
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# Create table, and insert rows, each in a separate transaction
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# Disable synchronous_commit to make this initialization go faster.
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#
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# Each row contains current insert LSN and the current timestamp, when
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# the row was inserted.
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cur.execute("SET synchronous_commit=off")
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cur.execute("CREATE TABLE foo (x integer)")
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tbl = []
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for i in range(1000):
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cur.execute(f"INSERT INTO foo VALUES({i})")
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# Get the timestamp at UTC
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after_timestamp = query_scalar(cur, "SELECT clock_timestamp()").replace(tzinfo=None)
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tbl.append([i, after_timestamp])
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# Execute one more transaction with synchronous_commit enabled, to flush
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# all the previous transactions
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cur.execute("INSERT INTO foo VALUES (-1)")
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# Wait until WAL is received by pageserver
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wait_for_last_flush_lsn(env, pgmain, env.initial_tenant, new_timeline_id)
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with env.pageserver.http_client() as client:
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# Check edge cases: timestamp in the future
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probe_timestamp = tbl[-1][1] + timedelta(hours=1)
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result = client.timeline_get_lsn_by_timestamp(
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env.initial_tenant, new_timeline_id, f"{probe_timestamp.isoformat()}Z"
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)
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assert result == "future"
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# timestamp too the far history
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probe_timestamp = tbl[0][1] - timedelta(hours=10)
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result = client.timeline_get_lsn_by_timestamp(
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env.initial_tenant, new_timeline_id, f"{probe_timestamp.isoformat()}Z"
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)
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assert result == "past"
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# Probe a bunch of timestamps in the valid range
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for i in range(1, len(tbl), 100):
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probe_timestamp = tbl[i][1]
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lsn = client.timeline_get_lsn_by_timestamp(
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env.initial_tenant, new_timeline_id, f"{probe_timestamp.isoformat()}Z"
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)
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# Call get_lsn_by_timestamp to get the LSN
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# Launch a new read-only node at that LSN, and check that only the rows
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# that were supposed to be committed at that point in time are visible.
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pg_here = env.postgres.create_start(
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branch_name="test_lsn_mapping", node_name="test_lsn_mapping_read", lsn=lsn
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)
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assert pg_here.safe_psql("SELECT max(x) FROM foo")[0][0] == i
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pg_here.stop_and_destroy()
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