Question

我正在尝试使用Java从我的MySQL数据库中导入一些数据，查询返回大约15,000行，并且为了防止ResultSet耗尽内存，我逐个传输每个结果。

private static void addEdges(DirectedGraph<String, DefaultEdge> g) throws SQLException {
Statement selectID = null;
String selectSQL = "SELECT citations.paperid, papers.id FROM papers INNER JOIN citations ON citations.title = papers.title AND citations.year = papers.year;";


try {
    selectID = conn.createStatement(java.sql.ResultSet.TYPE_FORWARD_ONLY, java.sql.ResultSet.CONCUR_READ_ONLY);
    selectID.setFetchSize(Integer.MIN_VALUE);
    ResultSet rs = selectID.executeQuery(selectSQL);
    String from;
    String to;
    System.out.println("iterating");
    while(rs.next()) {
    from = rs.getString("paperid");
    to = rs.getString("id");
    g.addEdge(from, to);
    }
} catch (SQLException e) {
    e.printStackTrace();
} finally {
    if (selectID != null) {
    try {
        selectID.close();
        } catch (Exception e) {
            System.out.println("Error closing statement");
        }
    }
}
}

但是我现在收到此错误：

Exception in thread "main" java.lang.OutOfMemoryError: GC overhead limit exceeded
    at com.mysql.jdbc.MysqlIO.nextRow(MysqlIO.java:2092)
    at com.mysql.jdbc.RowDataDynamic.nextRecord(RowDataDynamic.java:406)
    at com.mysql.jdbc.RowDataDynamic.next(RowDataDynamic.java:385)
    at com.mysql.jdbc.RowDataDynamic.close(RowDataDynamic.java:163)
    at com.mysql.jdbc.ResultSetImpl.realClose(ResultSetImpl.java:7472)
    at com.mysql.jdbc.ResultSetImpl.close(ResultSetImpl.java:919)
    at com.mysql.jdbc.StatementImpl.realClose(StatementImpl.java:2617)
    at com.mysql.jdbc.StatementImpl.close(StatementImpl.java:580)

这是从selectID.close()引发的。这是奇怪的，因为它应该关闭的ResultSet应该只包含一行。尝试分配更多内存，但这个问题仍然存在，任何想法？（我正在使用JGraphT库来创建有向图）

JDBC MySQL导入GC超出限制超出

0 个答案: