jdbc查询硕大无比数据集内存溢出
今天使用jdbc的PreparedStatement查询语句如下：
- Class.forName( "com.mysql.jdbc.Driver" );
- String url = "jdbc:mysql://localhost:3306/translate?characterEncoding=utf8" ;
- String sql = "select id, title, search_title, content from article" ;
- Connection conn = DriverManager.getConnection(url, "root" , "123456" );
- PreparedStatement ps = conn.prepareStatement(sql);
- ResultSet rs = ps.executeQuery();
- rs.close();
- ps.close();
- conn.close();
总是报这个错误：
Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
at com.mysql.jdbc.Buffer.getBytes(Buffer.java:198)
at com.mysql.jdbc.Buffer.readLenByteArray(Buffer.java:318)
at com.mysql.jdbc.MysqlIO.extractNativeEncodedColumn(MysqlIO.java:3567)
at com.mysql.jdbc.MysqlIO.unpackBinaryResultSetRow(MysqlIO.java:3483)
at com.mysql.jdbc.MysqlIO.nextRow(MysqlIO.java:1391)
at com.mysql.jdbc.MysqlIO.readSingleRowSet(MysqlIO.java:2369)
at com.mysql.jdbc.MysqlIO.getResultSet(MysqlIO.java:451)
at com.mysql.jdbc.MysqlIO.readResultsForQueryOrUpdate(MysqlIO.java:2076)
at com.mysql.jdbc.MysqlIO.readAllResults(MysqlIO.java:1451)
at com.mysql.jdbc.ServerPreparedStatement.serverExecute(ServerPreparedStatement.java:1314)
at com.mysql.jdbc.ServerPreparedStatement.executeInternal(ServerPreparedStatement.java:740)
at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:1467)
但是从网上找到的doc说，默认情况下不会出这个问题的，因为java回自动的优化不会导致内存溢出的。百思不得其解。
后来无意找到一个介绍，这么来做
就是给url连接字符串添加2个属性即可：useCursorFetch=true&defaultFetchSize=100