Files
neon/test_runner/regress/test_lfc_resize.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

106 lines
3.7 KiB
Python

from __future__ import annotations
import random
import re
import subprocess
import threading
import time
from typing import TYPE_CHECKING
import pytest
from fixtures.log_helper import log
from fixtures.utils import USE_LFC
if TYPE_CHECKING:
from fixtures.neon_fixtures import NeonEnv, PgBin
@pytest.mark.timeout(600)
@pytest.mark.skipif(not USE_LFC, reason="LFC is disabled, skipping")
def test_lfc_resize(neon_simple_env: NeonEnv, pg_bin: PgBin):
"""
Test resizing the Local File Cache
"""
env = neon_simple_env
cache_dir = env.repo_dir / "file_cache"
cache_dir.mkdir(exist_ok=True)
env.create_branch("test_lfc_resize")
endpoint = env.endpoints.create_start(
"main",
config_lines=[
"neon.max_file_cache_size=1GB",
"neon.file_cache_size_limit=1GB",
],
)
n_resize = 10
scale = 20
def run_pgbench(connstr: str):
log.info(f"Start a pgbench workload on pg {connstr}")
pg_bin.run_capture(["pgbench", "-i", f"-s{scale}", connstr])
pg_bin.run_capture(["pgbench", "-c10", f"-T{n_resize}", "-Mprepared", "-S", connstr])
# Initializing the pgbench database can be very slow, especially on debug builds.
connstr = endpoint.connstr(options="-cstatement_timeout=300s")
thread = threading.Thread(target=run_pgbench, args=(connstr,), daemon=True)
thread.start()
conn = endpoint.connect()
cur = conn.cursor()
def get_lfc_size() -> tuple[int, int]:
lfc_file_path = endpoint.lfc_path()
lfc_file_size = lfc_file_path.stat().st_size
res = subprocess.run(
["ls", "-sk", lfc_file_path], check=True, text=True, capture_output=True
)
lfc_file_blocks = re.findall("([0-9A-F]+)", res.stdout)[0]
log.info(f"Size of LFC file {lfc_file_size}, blocks {lfc_file_blocks}")
return (lfc_file_size, lfc_file_blocks)
# For as long as pgbench is running, twiddle the LFC size once a second.
# Note that we launch this immediately, already while the "pgbench -i"
# initialization step is still running. That's quite a different workload
# than the actual pgbench benchamark run, so this gives us coverage of both.
while thread.is_alive():
# Vary the LFC size randomly within a range above what we will later
# decrease it to. This should ensure that the final size decrease
# is really doing something.
size = random.randint(192, 512)
cur.execute(f"alter system set neon.file_cache_size_limit='{size}MB'")
cur.execute("select pg_reload_conf()")
time.sleep(1)
thread.join()
# Fill LFC: seqscan should fetch the whole table in cache.
# It is needed for further correct evaluation of LFC file size
# (a sparse chunk of LFC takes less than 1 MB on disk).
cur.execute("select sum(abalance) from pgbench_accounts")
# Before shrinking the cache, check that it really is large now
(lfc_file_size, lfc_file_blocks) = get_lfc_size()
assert int(lfc_file_blocks) > 128 * 1024
# At the end, set it at 100 MB, and perform a final check that the disk usage
# of the file is in that ballbark.
#
# We retry the check a few times, because it might take a while for the
# system to react to changing the setting and shrinking the file.
cur.execute("alter system set neon.file_cache_size_limit='100MB'")
cur.execute("select pg_reload_conf()")
nretries = 10
while True:
(lfc_file_size, lfc_file_blocks) = get_lfc_size()
assert lfc_file_size <= 512 * 1024 * 1024
if int(lfc_file_blocks) <= 128 * 1024 or nretries == 0:
break
nretries = nretries - 1
time.sleep(1)
assert int(lfc_file_blocks) <= 128 * 1024