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revert: static global init logical size limiter (#4368)

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added in #4366. revert for testing without it; it may have unintenteded
side-effects, and it's very difficult to understand the results from the
10k load testing environments. earlier results:
https://github.com/neondatabase/neon/pull/4366#issuecomment-1567491064
This commit is contained in:
Joonas Koivunen
2023-05-30 10:40:37 +03:00
committed by GitHub
parent cb83495744
commit db14355367
1 changed files with 0 additions and 16 deletions
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16
pageserver/src/tenant/timeline.rs
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@@ -1911,22 +1911,6 @@ impl Timeline {
// to spawn_ondemand_logical_size_calculation.
let cancel = CancellationToken::new();
/// Ugly, but necessary until `spawn_blocking` is used for blocking I/O, otherwise
/// we could lock up all worker threads.
static GLOBAL_INITIAL_LOGICAL_SIZES_AT_ONCE: once_cell::sync::Lazy<Arc<tokio::sync::Semaphore>> = once_cell::sync::Lazy::new(|| {
let cores = std::thread::available_parallelism();
// half rationale: we have other blocking work which will start later:
// consumption metrics and per timeline eviction task. we however need to
// be fast to accept page reads, so perhaps this is a suitable middle ground?
let max_blocked_threads = cores.map(|count| count.get() / 2);
let max_blocked_threads = max_blocked_threads.unwrap_or(1);
let max_blocked_threads = std::cmp::max(1, max_blocked_threads);
tracing::info!("using max {max_blocked_threads} threads for initial logical size");
Arc::new(tokio::sync::Semaphore::new(max_blocked_threads))
});
let _permit = GLOBAL_INITIAL_LOGICAL_SIZES_AT_ONCE.clone().acquire_owned().await.expect("global semaphore is never closed");
let calculated_size = match self_clone
.logical_size_calculation_task(lsn, LogicalSizeCalculationCause::Initial, &background_ctx, cancel)
.await