coins: increase default `dbbatchsize` to 32 MiB
What the developer wrote
Authored by Lőrinc
coins: increase default `dbbatchsize` to 32 MiB
The default database write batch size is increased from 16 MiB to 32 MiB to improve I/O efficiency and performance during UTXO flushes, particularly during Initial Block Download and `assumeutxo` loads.
On systems with slower I/O, a larger batch size reduces overhead from numerous small writes. Measurements show this change provides a modest performance improvement on most hardware during a critical section, with a minimal peak memory increase (approx. 75 MiB on default settings).
What changed, and why it matters
This commit simply doubles a default internal setting that controls how much data Bitcoin Core groups together before writing to its UTXO database. It is a performance tuning change, not a security fix or vulnerability. There is no indication it introduces a security problem.
No security action needed. Treat as routine performance optimization.
Security signals we found
No strong security signals were identified.
Evidence from the diff
The change increases DEFAULT_DB_CACHE_BATCH from 16 MiB to 32 MiB in src/kernel/caches.h. This affects LevelDB write batch sizing during UTXO flushes (IBD, assumeutxo loads). The commit message frames it purely as an I/O efficiency/performance improvement with a small memory trade-off (~75 MiB peak on default settings). No security relevance is claimed.
Changed components
src/kernel/caches.hInspect captured patch +1 / −1
diff --git a/src/kernel/caches.h b/src/kernel/caches.h
index 63bb44c5..aa3214e5 100644
--- a/src/kernel/caches.h
+++ b/src/kernel/caches.h
@@ -12,7 +12,7 @@
//! Suggested default amount of cache reserved for the kernel (bytes)
static constexpr size_t DEFAULT_KERNEL_CACHE{450_MiB};
//! Default LevelDB write batch size
-static constexpr size_t DEFAULT_DB_CACHE_BATCH{16_MiB};
+static constexpr size_t DEFAULT_DB_CACHE_BATCH{32_MiB};
//! Max memory allocated to block tree DB specific cache (bytes)
static constexpr size_t MAX_BLOCK_DB_CACHE{2_MiB};
Why this scored 15/100
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