diff --git a/src/main.cpp b/src/main.cpp index a1b3b8190..28582e048 100644 --- a/src/main.cpp +++ b/src/main.cpp @@ -1880,6 +1880,8 @@ enum FlushStateMode { bool static FlushStateToDisk(CValidationState &state, FlushStateMode mode) { LOCK2(cs_main, cs_LastBlockFile); static int64_t nLastWrite = 0; + static int64_t nLastFlush = 0; + static int64_t nLastSetChain = 0; std::set setFilesToPrune; bool fFlushForPrune = false; try { @@ -1893,16 +1895,36 @@ bool static FlushStateToDisk(CValidationState &state, FlushStateMode mode) { } } } - if ((mode == FLUSH_STATE_ALWAYS) || - ((mode == FLUSH_STATE_PERIODIC || mode == FLUSH_STATE_IF_NEEDED) && pcoinsTip->DynamicMemoryUsage() > nCoinCacheUsage) || - (mode == FLUSH_STATE_PERIODIC && GetTimeMicros() > nLastWrite + DATABASE_WRITE_INTERVAL * 1000000) || - fFlushForPrune) { - // Typical CCoins structures on disk are around 100 bytes in size. + int64_t nNow = GetTimeMicros(); + // Avoid writing/flushing immediately after startup. + if (nLastWrite == 0) { + nLastWrite = nNow; + } + if (nLastFlush == 0) { + nLastFlush = nNow; + } + if (nLastSetChain == 0) { + nLastSetChain = nNow; + } + size_t cacheSize = pcoinsTip->DynamicMemoryUsage(); + // The cache is large and close to the limit, but we have time now (not in the middle of a block processing). + bool fCacheLarge = mode == FLUSH_STATE_PERIODIC && cacheSize * (10.0/9) > nCoinCacheUsage; + // The cache is over the limit, we have to write now. + bool fCacheCritical = mode == FLUSH_STATE_IF_NEEDED && cacheSize > nCoinCacheUsage; + // 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. + bool fPeriodicWrite = mode == FLUSH_STATE_PERIODIC && nNow > nLastWrite + (int64_t)DATABASE_WRITE_INTERVAL * 1000000; + // It's been very long since we flushed the cache. Do this infrequently, to optimize cache usage. + bool fPeriodicFlush = mode == FLUSH_STATE_PERIODIC && nNow > nLastFlush + (int64_t)DATABASE_FLUSH_INTERVAL * 1000000; + // Combine all conditions that result in a full cache flush. + bool fDoFullFlush = (mode == FLUSH_STATE_ALWAYS) || fCacheLarge || fCacheCritical || fPeriodicFlush || fFlushForPrune; + // Write blocks and block index to disk. + if (fDoFullFlush || fPeriodicWrite) { + // Typical CCoins structures on disk are around 128 bytes in size. // Pushing a new one to the database can cause it to be written // twice (once in the log, and once in the tables). This is already // an overestimation, as most will delete an existing entry or // overwrite one. Still, use a conservative safety factor of 2. - if (!CheckDiskSpace(100 * 2 * 2 * pcoinsTip->GetCacheSize())) + if (fDoFullFlush && !CheckDiskSpace(128 * 2 * 2 * pcoinsTip->GetCacheSize())) return state.Error("out of disk space"); // First make sure all block and undo data is flushed to disk. FlushBlockFile(); @@ -1924,21 +1946,24 @@ bool static FlushStateToDisk(CValidationState &state, FlushStateMode mode) { return state.Abort("Files to write to block index database"); } } - // Flush the chainstate (which may refer to block index entries). - if (!pcoinsTip->Flush()) - return state.Abort("Failed to write to coin database"); - // Finally remove any pruned files if (fFlushForPrune) { UnlinkPrunedFiles(setFilesToPrune); fCheckForPruning = false; } - + nLastWrite = nNow; + } + // Flush best chain related state. This can only be done if the blocks / block index write was also done. + if (fDoFullFlush) { + // Flush the chainstate (which may refer to block index entries). + if (!pcoinsTip->Flush()) + return state.Abort("Failed to write to coin database"); + nLastFlush = nNow; + } + if ((mode == FLUSH_STATE_ALWAYS || mode == FLUSH_STATE_PERIODIC) && nNow > nLastSetChain + (int64_t)DATABASE_WRITE_INTERVAL * 1000000) { // Update best block in wallet (so we can detect restored wallets). - if (mode != FLUSH_STATE_IF_NEEDED) { - GetMainSignals().SetBestChain(chainActive.GetLocator()); - } - nLastWrite = GetTimeMicros(); + GetMainSignals().SetBestChain(chainActive.GetLocator()); + nLastSetChain = nNow; } } catch (const std::runtime_error& e) { return state.Abort(std::string("System error while flushing: ") + e.what()); diff --git a/src/main.h b/src/main.h index 2c4a4cb7c..fcbc4075d 100644 --- a/src/main.h +++ b/src/main.h @@ -82,8 +82,10 @@ static const unsigned int MAX_HEADERS_RESULTS = 2000; * degree of disordering of blocks on disk (which make reindexing and in the future perhaps pruning * harder). We'll probably want to make this a per-peer adaptive value at some point. */ static const unsigned int BLOCK_DOWNLOAD_WINDOW = 1024; -/** Time to wait (in seconds) between writing blockchain state to disk. */ -static const unsigned int DATABASE_WRITE_INTERVAL = 3600; +/** Time to wait (in seconds) between writing blocks/block index to disk. */ +static const unsigned int DATABASE_WRITE_INTERVAL = 60 * 60; +/** Time to wait (in seconds) between flushing chainstate to disk. */ +static const unsigned int DATABASE_FLUSH_INTERVAL = 24 * 60 * 60; /** Maximum length of reject messages. */ static const unsigned int MAX_REJECT_MESSAGE_LENGTH = 111;