//move the value under key to key2
status = db->Put(leveldb::WriteOptions(), key2, value);
assert(status.ok());
//delete
status = db->Delete(leveldb::WriteOptions(), key);
assert(status.ok());
status = db->Get(leveldb::ReadOptions(), key2, &value);
assert(status.ok());
std::cout << key2 << "===" << value << std::endl;
status = db->Get(leveldb::ReadOptions(), key, &value);
if (!status.ok())
std::cerr << key << " " << status.ToString() << std::endl;
else
std::cout << key << "===" << value << std::endl;
delete db;
return 0;
}
#define E(expr) CHECK((rc = (expr)) == MDB_SUCCESS, #expr)
#define RES(err, expr) ((rc = expr) == (err) || (CHECK(!rc, #expr), 0))
#define CHECK(test, msg) ((test) ? (void)0 : ((void)fprintf(stderr, \
"%s:%d: %s: %s\n", __FILE__, __LINE__, msg, mdb_strerror(rc)), abort()))
int test_LMDB()
{
//http://www.jianshu.com/p/yzFf8j
//./lmdb-mdb.master/libraries/liblmdb/mtest.c
int i = 0, j = 0, rc;
MDB_env *env;
MDB_dbi dbi;
MDB_val key, data;
MDB_txn *txn;
MDB_stat mst;
MDB_cursor *cursor, *cur2;
MDB_cursor_op op;
int count;
int *values;
char sval[32] = "";
srand(time(NULL));
count = (rand() % 384) + 64;
values = (int *)malloc(count*sizeof(int));
for (i = 0; i<count; i++) {
values[i] = rand() % 1024;
}
E(mdb_env_create(&env));
E(mdb_env_set_maxreaders(env, 1));
E(mdb_env_set_mapsize(env, 10485760));
//E(mdb_env_open(env, "./testdb", MDB_FIXEDMAP /*|MDB_NOSYNC*/, 0664));
E(mdb_env_open(env, "E:/tmp/testLMDB", MDB_FIXEDMAP /*|MDB_NOSYNC*/, 0664));
E(mdb_txn_begin(env, NULL, 0, &txn));
E(mdb_dbi_open(txn, NULL, 0, &dbi));
key.mv_size = sizeof(int);
key.mv_data = sval;
printf("Adding %d values\n", count);
for (i = 0; i<count; i++) {
sprintf(sval, "%03x %d foo bar", values[i], values[i]);
/* Set <data> in each iteration, since MDB_NOOVERWRITE may modify it */
data.mv_size = sizeof(sval);
data.mv_data = sval;
if (RES(MDB_KEYEXIST, mdb_put(txn, dbi, &key, &data, MDB_NOOVERWRITE))) {
j++;
data.mv_size = sizeof(sval);
data.mv_data = sval;
}
}
if (j) printf("%d duplicates skipped\n", j);
E(mdb_txn_commit(txn));
E(mdb_env_stat(env, &mst));
E(mdb_txn_begin(env, NULL, MDB_RDONLY, &txn));
E(mdb_cursor_open(txn, dbi, &cursor));
while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT)) == 0) {
printf("key: %p %.*s, data: %p %.*s\n",
key.mv_data, (int)key.mv_size, (char *)key.mv_data,
data.mv_data, (int)data.mv_size, (char *)data.mv_data);
}
CHECK(rc == MDB_NOTFOUND, "mdb_cursor_get");
mdb_cursor_close(cursor);
mdb_txn_abort(txn);
j = 0;
key.mv_data = sval;
for (i = count - 1; i > -1; i -= (rand() % 5)) {
j++;
txn = NULL;
E(mdb_txn_begin(env, NULL, 0, &txn));
sprintf(sval, "%03x ", values[i]);
if (RES(MDB_NOTFOUND, mdb_del(txn, dbi, &key, NULL))) {
j--;
mdb_txn_abort(txn);
}
else {
E(mdb_txn_commit(txn));
}
}
free(values);
printf("Deleted %d values\n", j);
E(mdb_env_stat(env, &mst));
E(mdb_txn_begin(env, NULL, MDB_RDONLY, &txn));
E(mdb_cursor_open(txn, dbi, &cursor));
printf("Cursor next\n");
while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT)) == 0) {
printf("key: %.*s, data: %.*s\n",
(int)key.mv_size, (char *)key.mv_data,
(int)data.mv_size, (char *)data.mv_data);
}
CHECK(rc == MDB_NOTFOUND, "mdb_cursor_get");
printf("Cursor last\n");
E(mdb_cursor_get(cursor, &key, &data, MDB_LAST));
printf("key: %.*s, data: %.*s\n",
(int)key.mv_size, (char *)key.mv_data,
(int)data.mv_size, (char *)data.mv_data);
printf("Cursor prev\n");
while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_PREV)) == 0) {
printf("key: %.*s, data: %.*s\n",
(int)key.mv_size, (char *)key.mv_data,
(int)data.mv_size, (char *)data.mv_data);
}
CHECK(rc == MDB_NOTFOUND, "mdb_cursor_get");
printf("Cursor last/prev\n");
E(mdb_cursor_get(cursor, &key, &data, MDB_LAST));
printf("key: %.*s, data: %.*s\n",
(int)key.mv_size, (char *)key.mv_data,
(int)data.mv_size, (char *)data.mv_data);
E(mdb_cursor_get(cursor, &key, &data, MDB_PREV));
printf("key: %.*s, data: %.*s\n",
(int)key.mv_size, (char *)key.mv_data,
(int)data.mv_size, (char *)data.mv_data);
mdb_cursor_close(cursor);
mdb_txn_abort(txn);