From 1ca23b47fd628cf8d8a1e46fc15ba8abe228bde5 Mon Sep 17 00:00:00 2001 From: Kosntantin Knizhnik Date: Thu, 17 Jul 2025 22:10:25 +0300 Subject: [PATCH] Add comment to the test --- test_runner/performance/test_unlogged.py | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/test_runner/performance/test_unlogged.py b/test_runner/performance/test_unlogged.py index 6f76c94c31..906f44dfb8 100644 --- a/test_runner/performance/test_unlogged.py +++ b/test_runner/performance/test_unlogged.py @@ -9,6 +9,10 @@ if TYPE_CHECKING: from fixtures.neon_fixtures import NeonEnvBuilder +# This test checks that the is no race between end of unlogged build and backends evicting pages of this index. +# We need to create quite large index (more than one gigabyte segment) to reproduce write error caused by this race condition +# (backend completed unlogged build removes local files while backend evicting page tries to write to the file). +# If index size is smaller than segment size, the problem is avoided by file descriptor cache which prevents file deletion. @pytest.mark.timeout(10000) def test_unlogged(neon_env_builder: NeonEnvBuilder): n_tables = 20