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https://github.com/neondatabase/neon.git
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ab073696d0
Replace `seqscan_prefetch_buffers` with `effective_io_concurrency` & `maintenance_io_concurrency` in one more place (the last one!)
64 lines
2.3 KiB
Python
64 lines
2.3 KiB
Python
import pytest
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from fixtures.neon_fixtures import NeonEnvBuilder, wait_for_last_flush_lsn
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#
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# Benchmark effect of prefetch on bulk update operations
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#
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# A sequential scan that's part of a bulk update is the same as any other sequential scan,
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# but dirtying the pages as you go affects the last-written LSN tracking. We used to have
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# an issue with the last-written LSN cache where rapidly evicting dirty pages always
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# invalidated the prefetched responses, which showed up in bad performance in this test.
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#
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@pytest.mark.timeout(10000)
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@pytest.mark.parametrize("fillfactor", [10, 50, 100])
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def test_bulk_update(neon_env_builder: NeonEnvBuilder, zenbenchmark, fillfactor):
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env = neon_env_builder.init_start()
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n_records = 1000000
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timeline_id = env.neon_cli.create_branch("test_bulk_update")
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tenant_id = env.initial_tenant
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pg = env.postgres.create_start("test_bulk_update")
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cur = pg.connect().cursor()
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cur.execute("set statement_timeout=0")
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cur.execute(f"create table t(x integer) WITH (fillfactor={fillfactor})")
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with zenbenchmark.record_duration("insert-1"):
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cur.execute(f"insert into t values (generate_series(1,{n_records}))")
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cur.execute("vacuum t")
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wait_for_last_flush_lsn(env, pg, tenant_id, timeline_id)
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with zenbenchmark.record_duration("update-no-prefetch"):
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cur.execute("update t set x=x+1")
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cur.execute("vacuum t")
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wait_for_last_flush_lsn(env, pg, tenant_id, timeline_id)
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with zenbenchmark.record_duration("delete-no-prefetch"):
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cur.execute("delete from t")
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cur.execute("drop table t")
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cur.execute("set enable_seqscan_prefetch=on")
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cur.execute("set effective_io_concurrency=32")
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cur.execute("set maintenance_io_concurrency=32")
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cur.execute(f"create table t2(x integer) WITH (fillfactor={fillfactor})")
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with zenbenchmark.record_duration("insert-2"):
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cur.execute(f"insert into t2 values (generate_series(1,{n_records}))")
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cur.execute("vacuum t2")
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wait_for_last_flush_lsn(env, pg, tenant_id, timeline_id)
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with zenbenchmark.record_duration("update-with-prefetch"):
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cur.execute("update t2 set x=x+1")
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cur.execute("vacuum t2")
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wait_for_last_flush_lsn(env, pg, tenant_id, timeline_id)
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with zenbenchmark.record_duration("delete-with-prefetch"):
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cur.execute("delete from t2")
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