Re: Performance SQL Delete vs RPGLE Delete

If you cannot use something like TRUNCATE or CLRPFM, and must resort to SQL "DELETE FROM tablename" you can delete all of the SQL INDEXes first, or remove all LF members, and remove any primary key constraints, because the access path maintenance is expensive, especially if you intend to just delete all the records anyway.  Then, re-add the indexes or LF members and primary key constraints before re-populating the file.

On Thursday, November 19, 2020, 6:40:01 PM EST, Charles Wilt <charles.wilt@xxxxxxxxx> wrote:

SQL would be faster...

However, assuming a 7.2+, use the TRUNCATE statement...

TRUNCATE MYTABLE
  DROP STORAGE
  IMMEDIATE;


On Thu, Nov 19, 2020 at 3:25 PM K Crawford <kscx3ksc@xxxxxxxxx> wrote:

I know the normal answer is, depends.  Just looking for thoughts.

I have a program (RPGLE) that has this code (the file has a lock on it
otherwise we would use CLRPFM or some other method).

  Read FileA;
  Dow not %eof(FileA);
      Delete FileAr;
      Read FileA;
  Enddo;

How would the performance compare to SQL with something like, in that same
RPGLE program.
  Exec SQL Set option Commit=*None
  Exec SQL Delete From FileA;

FileA will have 0.5 - 6 million rows.
--
Kerwin Crawford
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