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-rw-r--r--src/dbwrapper.cpp27
1 files changed, 26 insertions, 1 deletions
diff --git a/src/dbwrapper.cpp b/src/dbwrapper.cpp
index 4fad5d0c77..752f985bc0 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;
}