mirror of
https://github.com/neondatabase/neon.git
synced 2025-12-27 08:09:58 +00:00
42 lines
1.7 KiB
Python
42 lines
1.7 KiB
Python
# Test sequential scan speed
|
|
#
|
|
# The test table is large enough (3-4 MB) that it doesn't fit in the compute node
|
|
# cache, so the seqscans go to the page server. But small enough that it fits
|
|
# into memory in the page server.
|
|
from contextlib import closing
|
|
from dataclasses import dataclass
|
|
from fixtures.zenith_fixtures import ZenithEnv
|
|
from fixtures.log_helper import log
|
|
from fixtures.benchmark_fixture import MetricReport, ZenithBenchmarker
|
|
from fixtures.compare_fixtures import PgCompare
|
|
import pytest
|
|
|
|
|
|
@pytest.mark.parametrize('rows', [
|
|
pytest.param(100000),
|
|
pytest.param(1000000, marks=pytest.mark.slow),
|
|
])
|
|
def test_small_seqscans(zenith_with_baseline: PgCompare, rows: int):
|
|
env = zenith_with_baseline
|
|
|
|
with closing(env.pg.connect()) as conn:
|
|
with conn.cursor() as cur:
|
|
cur.execute('create table t (i integer);')
|
|
cur.execute(f'insert into t values (generate_series(1,{rows}));')
|
|
|
|
# Verify that the table is larger than shared_buffers
|
|
cur.execute('''
|
|
select setting::int * pg_size_bytes(unit) as shared_buffers, pg_relation_size('t') as tbl_ize
|
|
from pg_settings where name = 'shared_buffers'
|
|
''')
|
|
row = cur.fetchone()
|
|
shared_buffers = row[0]
|
|
table_size = row[1]
|
|
log.info(f"shared_buffers is {shared_buffers}, table size {table_size}")
|
|
assert int(shared_buffers) < int(table_size)
|
|
env.zenbenchmark.record("table_size", table_size, 'bytes', MetricReport.TEST_PARAM)
|
|
|
|
with env.record_duration('run'):
|
|
for i in range(1000):
|
|
cur.execute('select count(*) from t;')
|