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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
49 lines
1.9 KiB
Python
49 lines
1.9 KiB
Python
# Test sequential scan speed
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#
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from contextlib import closing
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from dataclasses import dataclass
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from fixtures.neon_fixtures import NeonEnv
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from fixtures.log_helper import log
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from fixtures.benchmark_fixture import MetricReport, NeonBenchmarker
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from fixtures.compare_fixtures import PgCompare
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import pytest
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@pytest.mark.parametrize(
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'rows,iters,workers',
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[
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# The test table is large enough (3-4 MB) that it doesn't fit in the compute node
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# cache, so the seqscans go to the page server. But small enough that it fits
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# into memory in the page server.
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pytest.param(100000, 100, 0),
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# Also test with a larger table, with and without parallelism
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pytest.param(10000000, 1, 0),
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pytest.param(10000000, 1, 4)
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])
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def test_seqscans(neon_with_baseline: PgCompare, rows: int, iters: int, workers: int):
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env = neon_with_baseline
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with closing(env.pg.connect()) as conn:
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with conn.cursor() as cur:
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cur.execute('create table t (i integer);')
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cur.execute(f'insert into t values (generate_series(1,{rows}));')
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# Verify that the table is larger than shared_buffers
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cur.execute('''
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select setting::int * pg_size_bytes(unit) as shared_buffers, pg_relation_size('t') as tbl_ize
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from pg_settings where name = 'shared_buffers'
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''')
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row = cur.fetchone()
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assert row is not None
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shared_buffers = row[0]
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table_size = row[1]
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log.info(f"shared_buffers is {shared_buffers}, table size {table_size}")
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assert int(shared_buffers) < int(table_size)
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env.zenbenchmark.record("table_size", table_size, 'bytes', MetricReport.TEST_PARAM)
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cur.execute(f"set max_parallel_workers_per_gather = {workers}")
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with env.record_duration('run'):
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for i in range(iters):
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cur.execute('select count(*) from t;')
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