How to avoid OOM (Out of memory) error when retrieving all records from huge table?

Question

I am given a task to convert a huge table to custom XML file. I will be using Java for this job.

If I simply issue a \"SELECT * FROM customer\", it may return huge a

Answer 1

With a little more information I can get a more helpful answer.

If you are using MySQL:

stmt = conn.createStatement(java.sql.ResultSet.TYPE_FORWARD_ONLY,
       java.sql.ResultSet.CONCUR_READ_ONLY);
stmt.setFetchSize(Integer.MIN_VALUE);

from http://www.oracle.com/technology/tech/java/sqlj_jdbc/htdocs/jdbc_faq.html:

java.util.Properties info = new java.util.Properties();
info.put ("user", "scott");
info.put ("password","tiger");
info.put ("defaultRowPrefetch","15");
getConnection ("jdbc:oracle:oci:@",info);