ctdb is a simple & lightweight key-value database, based on Append-only Compressed Trie.
- Add a new key/value pair to the database.
- Delete an existing key from the database.
- Querying the database by a specific key.
- Traverse the database by a specific prefix.
- Support for transactions.
make simple; ./simple
make trans; ./trans
make iter; ./iter
put & del:
struct ctdb *db = ctdb_open("./test.db");
struct ctdb_transaction *trans = ctdb_transaction_begin(db);
ctdb_put(trans, "apple", 5, "apple_value", 11);
ctdb_put(trans, "app", 3, "app_value", 9);
ctdb_put(trans, "application", 11, "application_value", 17);
ctdb_del(trans, "app", 3);
ctdb_transaction_commit(trans);
//ctdb_transaction_rollback(trans);
ctdb_transaction_free(trans);
ctdb_close(db);get:
struct ctdb *db = ctdb_open("./test.db");
struct ctdb_leaf leaf = ctdb_get(db, "app", 3);
//seek(db->fd, leaf.value_pos, SEEK_SET)
//read(db->fd, buffer, leaf.value_len)) or sendfile(client_fd, db->fd, &off, leaf.value_len)
ctdb_close(db);traverse:
struct ctdb *db = ctdb_open("./test.db");
//traverse callback
int traversal(char *key, int key_len, struct ctdb_leaf leaf){
printf("key:%.*s value_len:%u\n", key_len, key, leaf->value_len);
//return CTDB_ERR; //stop traversal
return CTDB_OK; //continue
}
//traverse all the data
if(CTDB_OK == ctdb_iterator_travel(db, "", 0, traversal)){
printf("end of traversal\n");
}
//traversing data starting with "app"
if(CTDB_OK == ctdb_iterator_travel(db, "app", 3, traversal)){
printf("end of traversal\n");
}
ctdb_close(db);