SQL query causing GC overhead limit exceeded in java

Question

I have a query that retrieves 2500 records in MySQL database. The problem is that its causing the GC overhead limit exceeded error in java. I don't know how to optimize my query to prevent his from happening. This is the code:

public static List<List<String>> getLogs(){
    sql = new String("SELECT EmpID, ValidDate, GROUP_CONCAT(ValidTime ORDER BY ValidTime ASC) AS logTime FROM logs WHERE Processed = 0 GROUP BY EmpID, ValidDate ORDER BY ValidDate ASC");
    List<List<String>> values = new ArrayList<>();
    List<String> id = new ArrayList<>();
    List<String> valDate = new ArrayList<>();
    List<String> logs = new ArrayList<>();

    try{
        stmt = data.createStatement();
        rs = stmt.executeQuery(sql);

        while(rs.next()){
            id.add(rs.getString("EmpID"));
            valDate.add(String.valueOf(rs.getDate("ValidDate"))); // This line of code produces the error mentioned in stacktrace
            logs.add(rs.getString("logTime"));
        }
    }catch(SQLException ex){
        ex.printStackTrace();
    }
    values.add(id);
    values.add(valDate);
    values.add(logs);

    return values;
}

Also, you're using parallel lists and *really* ought to be using a class. — chrylis -cautiouslyoptimistic-, Oct 26 '17 at 00:55
Yes as of now because I am in testing phase at the moment but in reality I need to process 800 employees multiply by 4 logs per day. — SilverRay, Oct 26 '17 at 00:56
check [this answer](https://stackoverflow.com/a/1393503/4648586) first.. since the issue seems related with how your application ate the memory, globally.. — Bagus Tesa, Oct 26 '17 at 00:58
Something like 3000 records shouldn't be any problem at all. It smells like there's something else going on here, and you'll really need to profile it. — chrylis -cautiouslyoptimistic-, Oct 26 '17 at 01:00
Java Mission Control, and what IDE are you using, it should have integrated one.. unless.. you are coding in notepad.. — Bagus Tesa, Oct 26 '17 at 01:03
you could put a log statement after each next() call and see if it blows up on row 1 or row 2500. i agree that 2500 rows it nothing and the number of rows is most likely not the cause of the issue — slipperyseal, Oct 26 '17 at 01:12
uhm sorry, I am trying to incorporate the logging system in the code but I'm having a hard time making it because I didn't use it yet. I only rely on every stacktrace that the error produces. — SilverRay, Oct 26 '17 at 01:39

score 0 · Answer 1 · answered Oct 26 '17 at 02:36

0

I solved my problem by just adding rs.close() in my code. Thanks for the responses and why's the downvote?

answered Oct 26 '17 at 02:36

SilverRay

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SQL query causing GC overhead limit exceeded in java

1 Answers1