Hello all, I have a database, which I query, and I'm unsure of where to perform the sorting of the results, so far I've have the following options.

• At the MySQL query.
• At list level(Using a LinkedList)
• Sorting an unsorted list using comparators before showing the results (basically in the jsp)

The List is composed by ObjectDTO so where would it be more efficient. Any ideas?

You should do the sorting in the database if at all possible.

• The database can use indexes. If there is a suitable index available then the results can be read from disk already in sorted order, resulting in a performance increase - no extra O(n log(n)) sorting step is required.
• If you only need the first x results you also minimize data transfer (both reduced network transfer, and also reduced disk access if there is a suitable index).

I have 3 text files c.dat, n.dat, and h.dat The contents are similar, in this format

c.dat    n.dat    h.dat
1 0.ccc  3 1.nnn  1 2.hhh
2 0.ccc  4 1.nnn  2 2.hhh
4 0.ccc  5 1.nnn  5 2.hhh

Desired output:

1 0.ccc Inf 2.hhh
2 0.ccc Inf 2.hhh
3 Inf 1.nnn Inf
4 0.ccc 1.nnn Inf
5 Inf 1.nnn 2.hhh
6 Inf Inf Inf
7 ....

Each file has ~100 rows, but they don't always start from 1, and don't aren't always consecutive.

I need to align the 3 files by the first column, such that if the other files don't have it, it's filled in with something like NA, or NaN, or Inf... anything.

Thanks!

awk '
{
        if(FNR==1){f++}
        a[$1,f] = $2
        if($1 > max){max = $1}
}

END{
        for(j=1;j<=max;j++){
          printf("%d\t", j)
          for(i=1;i<=f;i++){
            if(!a[j,i]){printf("Inf\t")}
            else{printf("%s\t", a[j,i])}
          }
          printf("\n")
        }
}' ./c.dat ./n.dat ./h.dat

Output

$ ./awk.dat
1       0.ccc   Inf     2.hhh
2       0.ccc   Inf     2.hhh
3       Inf     1.nnn   Inf
4       0.ccc   1.nnn   Inf
5       Inf     1.nnn   2.hhh