Speed up block downloading

src/db.cpp

@@ -84,8 +84,11 @@ CDB::CDB(const char* pszFile, const char* pszMode) : pdb(NULL)
             string strErrorFile = strDataDir + "/db.log";
             printf("dbenv.open strLogDir=%s strErrorFile=%s\n", strLogDir.c_str(), strErrorFile.c_str());
 
+            int nDbCache = GetArg("-dbcache", 25);
             dbenv.set_lg_dir(strLogDir.c_str());
-            dbenv.set_lg_max(10000000);
+            dbenv.set_cachesize(nDbCache / 1024, (nDbCache % 1024)*1048576, 1);
+            dbenv.set_lg_bsize(10485760);
+            dbenv.set_lg_max(104857600);
             dbenv.set_lk_max_locks(10000);
             dbenv.set_lk_max_objects(10000);
             dbenv.set_errfile(fopen(strErrorFile.c_str(), "a")); /// debug
@@ -156,7 +159,7 @@ void CDB::Close()
         nMinutes = 1;
     if (strFile == "addr.dat")
         nMinutes = 2;
-    if (strFile == "blkindex.dat" && IsInitialBlockDownload() && nBestHeight % 500 != 0)
+    if (strFile == "blkindex.dat" && IsInitialBlockDownload() && nBestHeight % 5000 != 0)
         nMinutes = 1;
     dbenv.txn_checkpoint(0, nMinutes, 0);
 

src/init.cpp

@@ -177,6 +177,7 @@ bool AppInit2(int argc, char* argv[])
             "  -min             \t\t  " + _("Start minimized") + "\n" +
             "  -splash          \t\t  " + _("Show splash screen on startup (default: 1)") + "\n" +
             "  -datadir=<dir>   \t\t  " + _("Specify data directory") + "\n" +
+            "  -dbcache=<n>     \t\t  " + _("Set database cache size in megabytes (default: 25)") + "\n" +
             "  -timeout=<n>     \t  "   + _("Specify connection timeout (in milliseconds)") + "\n" +
             "  -proxy=<ip:port> \t  "   + _("Connect through socks4 proxy") + "\n" +
             "  -dns             \t  "   + _("Allow DNS lookups for addnode and connect") + "\n" +