Make threshold for flushing more conservative.

Always leave a reasonable buffer of 50MB for usage from newly connected block (once over 50%) and increase the high water mark buffer to 200MB.

Github-Pull: #10133
Rebased-From: 1b55e07b7a61a9e6c299cf4c40fde80fa715d440

1 files changed, 3 insertions, 2 deletions

diff --git a/src/validation.cpp b/src/validation.cpp
index b85555072..c9135c442 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -2029,8 +2029,9 @@ bool static FlushStateToDisk(CValidationState &state, FlushStateMode mode, int n
     int64_t nMempoolSizeMax = GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000;
     int64_t cacheSize = pcoinsTip->DynamicMemoryUsage() * DB_PEAK_USAGE_FACTOR;
     int64_t nTotalSpace = nCoinCacheUsage + std::max<int64_t>(nMempoolSizeMax - nMempoolUsage, 0);
-    // The cache is large and we're within 10% and 100 MiB of the limit, but we have time now (not in the middle of a block processing).
-    bool fCacheLarge = mode == FLUSH_STATE_PERIODIC && cacheSize > std::max((9 * nTotalSpace) / 10, nTotalSpace - MAX_BLOCK_COINSDB_USAGE * 1024 * 1024);
+    // The cache is large and we're within 10% and 200 MiB or 50% and 50MiB of the limit, but we have time now (not in the middle of a block processing).
+    bool fCacheLarge = mode == FLUSH_STATE_PERIODIC && cacheSize > std::min(std::max(nTotalSpace / 2, nTotalSpace - MIN_BLOCK_COINSDB_USAGE * 1024 * 1024),
+                                                                            std::max((9 * nTotalSpace) / 10, nTotalSpace - MAX_BLOCK_COINSDB_USAGE * 1024 * 1024));
     // The cache is over the limit, we have to write now.
     bool fCacheCritical = mode == FLUSH_STATE_IF_NEEDED && cacheSize > nTotalSpace;
     // It's been a while since we wrote the block index to disk. Do this frequently, so we don't need to redownload after a crash.