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Update test_runner/performance/test_unlogged.py

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Co-authored-by: Heikki Linnakangas <heikki@neon.tech>
This commit is contained in:
Konstantin Knizhnik
2025-07-22 18:52:25 +03:00
committed by Konstantin Knizhnik
parent 388be47144
commit adf103a557
1 changed files with 4 additions and 4 deletions
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test_runner/performance/test_unlogged.py
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@@ -17,13 +17,13 @@ if TYPE_CHECKING:
# Originally Neon always called `mdexists` to check if the local file exists and determine if it's an unlogged relation. Now we check the cache first.
# mdexists is not so cheap: it closes and opens the file.
#
# This test tries to emulate situation when most of writes are with persistence=0.
# We create multiple connections to the database and in each fill it's own table. So each backends writes only it's own table and other tables
# descriptors are not cached. At the same time all backends perform eviction from shared buffers. Probability that backends evicts page of it's own
# This test tries to recreate the situation that most of writes are with persistence=0.
# We open multiple connections to the database and in each fill its own table. So each backends writes only its own table and other table's
# descriptors are not cached. At the same time all backends perform eviction from shared buffers. Probability that backends evicts page of its own
# relation is 1/N when N is number of relations=number of backends. The more relations, the smaller probability.
# For large enough number of relations most of writes are with unknown persistence.
#
# At Linux this test shows about 2x time speed improvement.
# On Linux, introducing the relpersistence cache shows about 2x time speed improvement in this test.
#
@pytest.mark.timeout(10000)
def test_unlogged(neon_env_builder: NeonEnvBuilder):