hiroppon https://blog.hatena.ne.jp/hiroppon/ 中年engineerの独り言 - crumbjp https://crumbjp.hateblo.jp/ mongodb As you know, the default number type in MongoDB is 64-bit float. number ( 64-bit float) : double fraction 52-bit (Actually meaning 53-bit precision) exponent 11-bit sign 1-bit So "0x20000000000001=2^53+1" will cause overflow. > db.test.save({i:0x1fffffffffffff}) > db.test.save({i:0x20000000000000}) … 190 <iframe src="https://hatenablog-parts.com/embed?url=https%3A%2F%2Fcrumbjp.hateblo.jp%2Fentry%2F20130502%2F1367485998" title=" NumberLong(64-bit integer) in MongoDB was smaller than I expected... - 中年engineerの独り言 - crumbjp" class="embed-card embed-blogcard" scrolling="no" frameborder="0" style="display: block; width: 100%; height: 190px; max-width: 500px; margin: 10px 0px;"></iframe> Hatena Blog https://hatena.blog 2013-05-02 18:13:18 rich https://crumbjp.hateblo.jp/entry/20130502/1367485998 1.0 100%