From ccedbafd73514e0e5b58c1a6251029e84dadaea8 Mon Sep 17 00:00:00 2001 From: Evan Klitzke Date: Tue, 20 Feb 2018 17:25:24 -0500 Subject: Increase LevelDB max_open_files unless on 32-bit Unix. This change significantly increases IBD performance by increasing the amount of the UTXO index that can remain in memory. To ensure this doesn't cause problems in the future, a static_assert on the LevelDB version has been added, which must be updated by anyone upgrading LevelDB. --- src/dbwrapper.cpp | 27 ++++++++++++++++++++++++++- 1 file changed, 26 insertions(+), 1 deletion(-) (limited to 'src/dbwrapper.cpp') diff --git a/src/dbwrapper.cpp b/src/dbwrapper.cpp index fb0d4215a2..fef8eedd14 100644 --- a/src/dbwrapper.cpp +++ b/src/dbwrapper.cpp @@ -71,6 +71,31 @@ public: } }; +static void SetMaxOpenFiles(leveldb::Options *options) { + // On most platforms the default setting of max_open_files (which is 1000) + // is optimal. On Windows using a large file count is OK because the handles + // do not interfere with select() loops. On 64-bit Unix hosts this value is + // also OK, because up to that amount LevelDB will use an mmap + // implementation that does not use extra file descriptors (the fds are + // closed after being mmaped). + // + // Increasing the value beyond the default is dangerous because LevelDB will + // fall back to a non-mmap implementation when the file count is too large. + // On 32-bit Unix host we should decrease the value because the handles use + // up real fds, and we want to avoid fd exhaustion issues. + // + // See PR #12495 for further discussion. + + int default_open_files = options->max_open_files; +#ifndef WIN32 + if (sizeof(void*) < 8) { + options->max_open_files = 64; + } +#endif + LogPrint(BCLog::LEVELDB, "LevelDB using max_open_files=%d (default=%d)\n", + options->max_open_files, default_open_files); +} + static leveldb::Options GetOptions(size_t nCacheSize) { leveldb::Options options; @@ -78,13 +103,13 @@ static leveldb::Options GetOptions(size_t nCacheSize) options.write_buffer_size = nCacheSize / 4; // up to two write buffers may be held in memory simultaneously options.filter_policy = leveldb::NewBloomFilterPolicy(10); options.compression = leveldb::kNoCompression; - options.max_open_files = 64; options.info_log = new CBitcoinLevelDBLogger(); if (leveldb::kMajorVersion > 1 || (leveldb::kMajorVersion == 1 && leveldb::kMinorVersion >= 16)) { // LevelDB versions before 1.16 consider short writes to be corruption. Only trigger error // on corruption in later versions. options.paranoid_checks = true; } + SetMaxOpenFiles(&options); return options; } -- cgit v1.2.3