lmdb-safe/examples/scale.cc

#include "../lmdb-safe.hh"

#include <c++utilities/conversion/stringconversion.h>

using namespace std;
using namespace LMDBSafe;

struct MDBVal
{
  MDBVal(unsigned int v) : d_v(v)
  {
    d_mdbval.mv_size = sizeof(d_v);
    d_mdbval.mv_data = &d_v;
  }
  operator const MDB_val&()
  {
    return d_mdbval;
  }
  unsigned int d_v;
  MDB_val d_mdbval;
};


int main(int argc, char** argv)
{
  auto env = getMDBEnv("./database", MDB_NOSUBDIR, 0600);
  auto dbi = env->openDB(std::string_view(), MDB_CREATE | MDB_INTEGERKEY);
  auto txn = env->getRWTransaction();

  unsigned int limit=20;
  if(argc > 1)
    limit = CppUtilities::stringToNumber<unsigned int>(argv[1]);
  
  cout<<"Counting records.. "; cout.flush();
  auto cursor = txn->getCursor(dbi);
  MDBOutVal key, data;
  int count=0;
  while(!cursor.get(key, data, count ? MDB_NEXT : MDB_FIRST)) {
    auto d = data.get<unsigned long>();
    if(d==17)
      cout <<"Got 17!"<<endl;
    count++;
  }
  cout<<"Have "<<count<<"!"<<endl;
  
  cout<<"Clearing records.. "; cout.flush();
  mdb_drop(*txn, dbi, 0); // clear records
  cout<<"Done!"<<endl;

  cout << "Adding "<<limit<<" values  .. "; cout.flush();
  for(unsigned long n = 0 ; n < limit; ++n) {
    txn->put(dbi, n, n, MDB_APPEND);
  }
  cout <<"Done!"<<endl;
  cout <<"Calling commit.. "; cout.flush();
  txn->commit();
  cout<<"Done!"<<endl;
}