我遇到了 java OutOfMemoryError 的问题。该程序主要查看在 mysql workbench 上运行的 mysql 表,并查询它们以获取某些信息,然后将它们放入 CSV 文件中。
该程序适用于较小的数据集,但是一旦我使用较大的数据集(记录信息的小时数而不是可能的 40 分钟),我就会收到此错误,对我来说,问题来自拥有庞大的数据集以及程序没有很好地处理信息。或者无法以我的方式处理这么多的数据。
将 Java VM 参数设置为 -xmx1024m 适用于稍大的数据集,但我需要它来处理更大的数据集,但它会给出错误。
这是我很确定是某处程序的原因的方法:
// CSV is csvwriter (external lib), sment are Statements, rs is a ResultSet
public void pidsforlog() throws IOException
{
String[] procs;
int count = 0;
String temp = "";
System.out.println("Commence getting PID's out of Log");
try {
sment = con.createStatement();
sment2 = con.createStatement();
String query1a = "SELECT * FROM log, cpuinfo, memoryinfo";
rs = sment.executeQuery(query1a);
procs = new String[countThrough(rs)];
// SIMPLY GETS UNIQUE PROCESSES OUT OF TABLES AND STORES IN ARRAY
while (rs.next()) {
temp = rs.getString("Process");
if(Arrays.asList(procs).contains(temp)) {
} else {
procs[count] = temp;
count++;
}
}
// BELIEVE THE PROBLEM LIES BELOW HERE. SIZE OF THE RESULTSET TOO BIG?
for(int i = 0; i < procs.length; i++) {
if(procs[i] == null) {
} else {
String query = "SELECT DISTINCT * FROM log, cpuinfo, memoryinfo WHERE log.Process = " + "'" + procs[i] + "'" + " AND cpuinfo.Process = " + "'" + procs[i] + "'" + " AND memoryinfo.Process = " + "'" + procs[i] + "' AND log.Timestamp = cpuinfo.Timestamp = memoryinfo.Timestamp";
System.out.println(query);
rs = sment.executeQuery(query);
writer = new CSVWriter(new FileWriter(procs[i] + ".csv"), ',');
writer.writeAll(rs, true);
writer.flush();
}
}
writer.close();
} catch (SQLException e) {
notify("Error pidslog", e);
}
}; // end of method
请随时询问您是否需要源代码或更多信息,因为我急于解决这个问题!
谢谢。