From ac11dddc92a5942b29bce4b75fc92b03a73c096f Mon Sep 17 00:00:00 2001
From: jgrusewski <jgrusewski@localhost>
Date: Sun, 24 May 2026 23:11:03 +0200
Subject: [PATCH] fix(ml-features): imbalance bar cache on persistent PVC, not
 /tmp
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Cache path moved from /tmp/.foxhunt_imbalance_cache/ (ephemeral,
lost between Argo pods) to <mbp10_dir>/.cache/ (on the training-data
PVC). Saves ~4 minutes per Argo submission by avoiding recomputation
of 209M trade ticks → 17.8M imbalance bars.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
---
 crates/ml-features/src/mbp10_loader.rs | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/crates/ml-features/src/mbp10_loader.rs b/crates/ml-features/src/mbp10_loader.rs
index 6e0fe775b..bcdb5a2f3 100644
--- a/crates/ml-features/src/mbp10_loader.rs
+++ b/crates/ml-features/src/mbp10_loader.rs
@@ -556,23 +556,27 @@ fn collect_dbn_files(dir: &Path) -> Vec<std::path::PathBuf> {
 //
 // Computing imbalance bars from MBP-10 data requires decompressing ~19GB of
 // .dbn.zst files (~450s). This cache stores the resulting `Vec<OHLCVBar>` to
-// `/tmp/.foxhunt_imbalance_cache/<hash>.bars.bin` using bincode.
+// `<mbp10_dir>/.cache/<hash>.bars.bin` using bincode. Stored on the
+// persistent training-data PVC so it survives across Argo pod restarts.
 //
 // Cache key: DefaultHasher of (mbp10_dir, symbol, threshold bits, alpha bits).
 // Invalidation: cache mtime vs. newest .dbn/.dbn.zst file in the source dir.
 // ══════════════════════════════════════════════════════════════════════════════
 
-/// Compute a cache path for an imbalance bar set.
+/// Compute a cache path for an imbalance bar set. Stores alongside
+/// the source data on the persistent volume so the cache survives
+/// across Argo pod restarts.
 fn imbalance_cache_path(mbp10_dir: &Path, symbol: &str, threshold: f64, alpha: f64) -> std::path::PathBuf {
     use std::collections::hash_map::DefaultHasher;
     use std::hash::{Hash, Hasher};
     let mut hasher = DefaultHasher::new();
-    mbp10_dir.hash(&mut hasher);
     symbol.hash(&mut hasher);
     threshold.to_bits().hash(&mut hasher);
     alpha.to_bits().hash(&mut hasher);
     let hash = hasher.finish();
-    std::path::PathBuf::from(format!("/tmp/.foxhunt_imbalance_cache/{:016x}.bars.bin", hash))
+    let cache_dir = mbp10_dir.join(".cache");
+    let _ = std::fs::create_dir_all(&cache_dir);
+    cache_dir.join(format!("{:016x}.bars.bin", hash))
 }
 
 /// Check whether the cache file is newer than every `.dbn`/`.dbn.zst` file under `source_dir`.
@@ -856,7 +860,7 @@ pub fn imbalance_bars_sequential(trades: &[Mbp10Trade], threshold: f64) -> Vec<O
 /// Scans `mbp10_dir/symbol/` for `.dbn` and `.dbn.zst` files, loads each,
 /// extracts trades (action == 'T'), feeds into adaptive `ImbalanceBarSampler`.
 ///
-/// Results are cached to `/tmp/.foxhunt_imbalance_cache/<hash>.bars.bin`.
+/// Results are cached to `<mbp10_dir>/.cache/<hash>.bars.bin`.
 /// Subsequent calls with the same parameters return in <1s if no source files
 /// have changed.
 ///