REXX file read limit
Jay Pillai
which reads a file,
formats this input and creates an output file which is an input for
another program. I was wondering
if the input file gets too big, if my program will still function or will
it end with 'Machine resource exhausted'. as it does
when I run this rexx program in a foreground session.
Thanks in advance for your reply.
Jay
Khan, Moyeen , M.A.
chunk of records.
One Hand Clapping
limit is that imposed by how much memory is available to the logged on user or
batch job.
Jay Pillai wrote:
> Is there a limit how big a file, rexx can read?. <snip>
Isaac Yassin
As long as you don't do it one-by-one (too much I/O) - I use about 5000
records per EXECIO (sometimes I cheat myself and read more...)
Isaac Yassin
Jay Pillai
the next 5000 and so on till
the end of file. At the moment I do it like this. I am afraid if the
file gets too big Rexx could have a problem reading
the whole file at one go.
"execio * diskr indd (stem file. finis"
do i = 1 to file.0
/* some file processing done here and written to output
file */
End
Jay
Seibert, Dave
What the other responders to your question implied but didn't outright
state is that the Memory Exhausted problem is typically caused by excessive
memory tied up by variables.
Here is an example of avoiding that.
The program can be passed a heapsize parameter which controls how many
records are read in a chunk.
The critical part of freeing memory is the >drop ttlin.i< statement. This
is an old program. The more current version deals with more complications,
but this program was short enough to post.
The program reads a file (allocated outside this program) and changes a
portion of the record to uppercase, then writing it out to another file
(also allocated outside this program).
Excuse any syntax errors. They have to have been caused by adding comments.
Feel free to reply with questions.
/* Rexx */
arg heapsize Tr_parm
If Tr_parm <> '' then /* Set
debugging option if requested */
do;trace_on=1;Tr_stmt='TRACE 'Tr_parm;interpret Tr_stmt;end
else trace_on = 0
if heapsize = '' | heapsize = '.' then
heapsize = 1000 /* set default
heapsize if nulled or not supplied */
curr_line = 1;done = 0; j=0 /* initialize looping vars.
*/
do until done
"execio "heapsize" diskr ttlin" curr_line" (stem ttlin."
if rc = 2 then done = 1
do i = 1 to ttlin.0
up_name = translate(substr(ttlin.i,9,210))
outrec.i = overlay(up_name,ttlin.i,221,210)
end /* end do ttlin loop */
if trace_on then interpret Tr_stmt /* Debugging code */
drop ttlin.
outrec.0 = i - 1
"execio" outrec.0 "diskw outrec (stem outrec."
say writing Outrec.0 records
curr_line = curr_line + ttlin.0
end /* end outer loop */
"execio 0 diskw outrec (finis"
David Seibert
Compuware Corporation File-AID Product Architect
Dave.S...@Compuware.com
Thomas Berg
Something like:
rcode = 0
do Until rcode <> 0
"execio 5000 diskr indd (stem file."
rcode = rc
do i = 1 to file.0
/* some file processing done here and written to output file */
End
End
"execio 0 diskr indd (finis"
Thomas Berg
Jay Pillai skrev:
Erik P. Olsen
n = 5000
Do Forever
"execio" n "diskr indd (stem file."
eof? = rc=2
do i = 1 to file.0
/* some file processing done here and written to output file
*/
End
If eof? Then Leave
End
"execio 0 diskr indd (finis"
Gozzard, Mark
"ALLOC F(XXXX) DA("DSN") SHR"
CALL GET_RECORDS
DO WHILE FILE.0 > 0
DO XX = 1 TO FILE.0
CALL DO_WORK FILE.XX
END
CALL GET_RECORDS
END
"EXECIO 0 DISKR XXXX (FINIS"
"FREE F(XXXX)"
EXIT
GET_RECORDS:
"EXECIO 10000 DISKR XXXX(STEM FILE."
RETURN
DO_WORK: PROCEDURE
PARSE ARG RECORD
/* PROCESS YOU RECORD HERE !!!! */
SAY RECORD
RETURN
Mark Gozzard
Mailto:mark.g...@eds.com
-----Original Message-----
From: Jay Pillai [mailto:Jay_P...@SWISSRE.COM]
Sent: 13 December 2000 23:43
To: TSO-...@VM.MARIST.EDU
Subject: REXX file read limit