MCOL-505 Performance improvements to ExeMgr

This fix improves the performance of ExeMgr by doing the following:

* Significantly reduces the amount of time the xml configuration is
scanned
* Uses a much faster way to determine the CPU core count
* Reduces the amount of times certain allocations are executed
* Rowgroup pre-allocates vectors for 1024 rows

This improves performance for the first query of a connection and the
performance for smaller result sets. It may well improve performance in
other areas too.

utils/common/cgroupconfigurator.cpp

@@ -141,29 +141,7 @@ uint32_t CGroupConfigurator::getNumCoresFromProc()
 	GetSystemInfo(&siSysInfo);
 	return siSysInfo.dwNumberOfProcessors;
 #else
-	ifstream cpuinfo("/proc/cpuinfo");
-
-	if (!cpuinfo.good())
-		return 0;
-
-	unsigned nc = 0;
-
-	regex re("Processor\\s*:\\s*[0-9]+", regex::normal|regex::icase);
-
-	string line;
-
-	getline(cpuinfo, line);
-
-	unsigned i = 0;
-	while (i < 10000 && cpuinfo.good() && !cpuinfo.eof())
-	{
-		if (regex_match(line, re))
-			nc++;
-
-		getline(cpuinfo, line);
-
-		++i;
-	}
+    uint32_t nc = sysconf(_SC_NPROCESSORS_ONLN);
 
 	return nc;
 #endif

utils/configcpp/configcpp.cpp

@@ -32,6 +32,7 @@ using namespace std;
 
 #include <boost/thread.hpp>
 #include <boost/filesystem.hpp>
+#include <boost/unordered_map.hpp>
 using namespace boost;
 namespace fs=boost::filesystem;
 
@@ -82,8 +83,9 @@ Config* Config::makeConfig(const char* cf)
 {
 	mutex::scoped_lock lk(fInstanceMapMutex);
 
-	string configFile;
-	string installDir = startup::StartUp::installDir();
+	static string installDir;
+    if (installDir.empty())
+        installDir = startup::StartUp::installDir();
 
 	if (cf == 0)
 	{
@@ -96,18 +98,22 @@ Config* Config::makeConfig(const char* cf)
 #endif
 		if (cf == 0 || *cf == 0)
 		{
-			fs::path configFilePath = fs::path(installDir) / fs::path("etc") / defaultCalpontConfigFile;
-			configFile = configFilePath.string();
-		}
-		else
-		{
-			configFile = cf;
+            static string defaultFilePath;
+            if (defaultFilePath.empty())
+            {
+                fs::path configFilePath;
+                configFilePath = fs::path(installDir) / fs::path("etc") / defaultCalpontConfigFile;
+                defaultFilePath = configFilePath.string();
+            }
+            if (fInstanceMap.find(defaultFilePath) == fInstanceMap.end())
+        	{
+        		Config* instance = new Config(defaultFilePath, installDir);
+        		fInstanceMap[defaultFilePath] = instance;
+        	}
+            return fInstanceMap[defaultFilePath];
 		}
 	}
-	else
-	{
-		configFile = cf;
-	}
+	string configFile(cf);
 
 	if (fInstanceMap.find(configFile) == fInstanceMap.end())
 	{
@@ -241,7 +247,7 @@ const string Config::getConfig(const string& section, const string& name)
 		}
 	}
 
-	return fParser.getConfig(fDoc, section, name);
+    return fParser.getConfig(fDoc, section, name);
 }
 
 void Config::getConfig(const string& section, const string& name, vector<string>& values)

utils/rowgroup/rowgroup.cpp

@@ -800,7 +800,14 @@ int64_t Row::getSignedNullValue(uint32_t colIndex) const
 
 RowGroup::RowGroup() : columnCount(0), data(NULL), rgData(NULL), strings(NULL),
 	useStringTable(true), hasLongStringField(false), sTableThreshold(20)
-{ }
+{
+    oldOffsets.reserve(1024);
+    oids.reserve(1024);
+    keys.reserve(1024);
+    types.reserve(1024);
+    scale.reserve(1024);
+    precision.reserve(1024);
+}
 
 RowGroup::RowGroup(uint32_t colCount,
 	const vector<uint32_t> &positions,