Files
neon/test_runner/regress/test_lfc_working_set_approximation.py
Alexander Bayandin 30a7dd630c ruff: enable TC — flake8-type-checking (#11368)
## Problem

`TYPE_CHECKING` is used inconsistently across Python tests.

## Summary of changes
- Update `ruff`: 0.7.0 -> 0.11.2
- Enable TC (flake8-type-checking):
https://docs.astral.sh/ruff/rules/#flake8-type-checking-tc
- (auto)fix all new issues
2025-03-30 18:58:33 +00:00

120 lines
4.8 KiB
Python

from __future__ import annotations
import time
from pathlib import Path
from typing import TYPE_CHECKING
import pytest
from fixtures.log_helper import log
from fixtures.utils import USE_LFC, query_scalar
if TYPE_CHECKING:
from fixtures.neon_fixtures import NeonEnv
@pytest.mark.skipif(not USE_LFC, reason="LFC is disabled, skipping")
def test_lfc_working_set_approximation(neon_simple_env: NeonEnv):
env = neon_simple_env
cache_dir = Path(env.repo_dir) / "file_cache"
cache_dir.mkdir(exist_ok=True)
log.info("Creating endpoint with 1MB shared_buffers and 64 MB LFC")
endpoint = env.endpoints.create_start(
"main",
config_lines=["neon.max_file_cache_size='128MB'", "neon.file_cache_size_limit='64MB'"],
)
cur = endpoint.connect().cursor()
cur.execute("create extension neon")
log.info(f"preparing some data in {endpoint.connstr()}")
ddl = """
CREATE TABLE pgbench_accounts (
aid bigint NOT NULL,
bid integer,
abalance integer,
filler character(84),
-- more web-app like columns
text_column_plain TEXT DEFAULT repeat('NeonIsCool', 5),
jsonb_column_extended JSONB DEFAULT ('{ "tell everyone": [' || repeat('{"Neon": "IsCool"},',9) || ' {"Neon": "IsCool"}]}')::jsonb
)
WITH (fillfactor='100');
"""
cur.execute(ddl)
# prepare index access below
cur.execute(
"ALTER TABLE ONLY pgbench_accounts ADD CONSTRAINT pgbench_accounts_pkey PRIMARY KEY (aid)"
)
cur.execute(
"insert into pgbench_accounts(aid,bid,abalance,filler) select aid, (aid - 1) / 100000 + 1, 0, '' from generate_series(1, 100000) as aid;"
)
# ensure correct query plans and stats
cur.execute("vacuum ANALYZE pgbench_accounts")
# determine table size - working set should approximate table size after sequential scan
pages = query_scalar(cur, "SELECT relpages FROM pg_class WHERE relname = 'pgbench_accounts'")
log.info(f"pgbench_accounts has {pages} pages, resetting working set to zero")
cur.execute("select approximate_working_set_size(true)")
cur.execute(
'SELECT count(*) FROM pgbench_accounts WHERE abalance > 0 or jsonb_column_extended @> \'{"tell everyone": [{"Neon": "IsCool"}]}\'::jsonb'
)
# verify working set size after sequential scan matches table size and reset working set for next test
blocks = query_scalar(cur, "select approximate_working_set_size(true)")
log.info(f"working set size after sequential scan on pgbench_accounts {blocks}")
assert pages * 0.8 < blocks < pages * 1.2
# run a few point queries with index lookup
cur.execute("SELECT abalance FROM pgbench_accounts WHERE aid = 4242")
cur.execute("SELECT abalance FROM pgbench_accounts WHERE aid = 54242")
cur.execute("SELECT abalance FROM pgbench_accounts WHERE aid = 104242")
cur.execute("SELECT abalance FROM pgbench_accounts WHERE aid = 204242")
# verify working set size after some index access of a few select pages only
blocks = query_scalar(cur, "select approximate_working_set_size(true)")
log.info(f"working set size after some index access of a few select pages only {blocks}")
assert blocks < 12
@pytest.mark.skipif(not USE_LFC, reason="LFC is disabled, skipping")
def test_sliding_working_set_approximation(neon_simple_env: NeonEnv):
env = neon_simple_env
endpoint = env.endpoints.create_start(
branch_name="main",
config_lines=[
"autovacuum = off",
"shared_buffers=1MB",
"neon.max_file_cache_size=256MB",
"neon.file_cache_size_limit=245MB",
],
)
conn = endpoint.connect()
cur = conn.cursor()
cur.execute("create extension neon")
cur.execute(
"create table t(pk integer primary key, count integer default 0, payload text default repeat('?', 128))"
)
cur.execute("insert into t (pk) values (generate_series(1,1000000))")
time.sleep(2)
before_10k = time.monotonic()
cur.execute("select sum(count) from t where pk between 10000 and 20000")
time.sleep(2)
before_1k = time.monotonic()
cur.execute("select sum(count) from t where pk between 1000 and 2000")
after = time.monotonic()
cur.execute(f"select approximate_working_set_size_seconds({int(after - before_1k + 1)})")
estimation_1k = cur.fetchall()[0][0]
log.info(f"Working set size for selecting 1k records {estimation_1k}")
cur.execute(f"select approximate_working_set_size_seconds({int(after - before_10k + 1)})")
estimation_10k = cur.fetchall()[0][0]
log.info(f"Working set size for selecting 10k records {estimation_10k}")
cur.execute("select pg_table_size('t')")
size = cur.fetchall()[0][0] // 8192
log.info(f"Table size {size} blocks")
assert estimation_1k >= 20 and estimation_1k <= 40
assert estimation_10k >= 200 and estimation_10k <= 440