Re: C++, Postgres , libpqxx huge query

[alexandros_e <alexandros.ef@xxxxxxxxx>]

To answer my own question, I adapted How to use pqxx::stateless_cursor class
from libpqxx?

try {
        work W(*Conn);
        pqxx::stateless_cursor<pqxx::cursor_base::read_only,
pqxx::cursor_base::owned>
                cursor(W, sql[sqlLoad], "mycursor", false);
        /* Assume you know total number of records returned */
        for (size_t idx = 0; idx < countRecords; idx += 100000) {
            /* Fetch 100,000 records at a time */
            result r = cursor.retrieve(idx, idx + 100000);
            for (int rownum = 0; rownum < r.size(); ++rownum) {
                const result::tuple row = r[rownum];
                vid1 = row[0].as<int>();
                vid2 = row[1].as<int>();
                vid3 = row[2].as<int>();
                .............
            }
        }
    } catch (const std::exception &e) {
        std::cerr << e.what() << std::endl;
    }





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