sequential search without closing and reopening of a file

anand tr · New User Joined: 12 Aug 2008 Posts: 41 Location: chennai

Hi,
I have two flat files (file1 & file2) which i use in a program.The number of records in both the files are not constant (as they are daily updated).
I need to search whether the record present in file1 is also present in file2 and write the same to o/p.
I am opting for a simple sequential search(reading 1 record from file1 and comparing with all the records in file2) and its consuming lot of time as the files are huge.
each time end of file2 is reached am closing and reopening it so that the first record is fetched for the next iteration. Is there any method so that this opening and closing could be avoided?
I guess, neither the cobol table could be used as the number of records in both the files are not constant.

dick scherrer · Posted: Wed Sep 24, 2008 10:36 am

Hello,

anand tr · New User Joined: 12 Aug 2008 Posts: 41 Location: chennai

Thanks Dick,
But am not able to view/download the code. it says-"Sorry but you are not authorized to view or download this Attachment".

Escapa · Posted: Wed Sep 24, 2008 11:09 am

As told by dick you need to sort input files first
Then you can use below logic..

anand tr · New User Joined: 12 Aug 2008 Posts: 41 Location: chennai

Hi Dick,
I tried again and was able to download successfully. Thanks for that.

dick scherrer · Posted: Wed Sep 24, 2008 11:20 am

anand tr · New User Joined: 12 Aug 2008 Posts: 41 Location: chennai

Thanks Dick,
ll surely try and get back to u .I guess the performance wud b be surely increased with this method.

Escapa · Posted: Wed Sep 24, 2008 1:00 pm

Thanks Dick for pointing that out. Code is corrected

dbzTHEdinosauer · Posted: Wed Sep 24, 2008 2:05 pm

if you are going to sort the files anyway, why not employ one of the sort tricks to accomplish this rather easy task - with sort.

to write the code to accomplish this, one has to think.

anand tr · New User Joined: 12 Aug 2008 Posts: 41 Location: chennai

Thanks Dick,
I tried the way you suggested and successfully ran the code in few seconds(compared to the 1 hour which was very huge using the older method)..

Brenholtz ,
Could you suggest or elaborate a bit on hw we can i accomplish the same.

dick scherrer · Posted: Wed Sep 24, 2008 8:52 pm

Hello Sambhaji,

Escapa · Posted: Thu Sep 25, 2008 11:05 am

dick scherrer · Posted: Thu Sep 25, 2008 7:30 pm

Hi Sambhaji,

The first thing i noticed is that the program will not work when either of the files has more records than the other.

I suggest you download the code from the "Sticky" and compare that to your example code. Keep in mind that the code in the "Sticky" works in over 100 different production systems. I put that "model" together before vsam was available and when processing sequential files part of every application. You will probably need to right-click / save-as to get the file.

If you find anything in the "sticky" code that is not clear, post any questions back here.

Naveen_Babu · New User Joined: 18 Jan 2006 Posts: 1

Hi,

You can use a cobol table to store the file content and use 'Search All' it will increase the performance further. You have mentioned that the file record count is not fixed so can't use a internal table, you can use a table in this case also; How?

Table Declaration -
01 WT-TSET-TABLE.
03 WT-TEST OCCURS 0 TO 500000 TIMES
DEPENDING ON WT-P-MAX
ASCENDING KEY IS WT-P-Field1
INDEXED BY WT-P-IDX.
05 WT-P-Field1 PIC 9(9) COMP-3.
05 WT-P-Field2 PIC X(5).
05 WT-P-Field3 PIC X(1).

1) Give OCCURS a Max number of records file can have
2) While storing the file contents into the tables increment WT-P-MAX for every record stored, so WT-P-MAX contains the file record count.
3) As per the 'DEPENDING' clause the table is automatically define with the value of the WT-P-MAX field.

Hope this helps...

dick scherrer · Posted: Fri Sep 26, 2008 7:59 pm

Hello Naveen and welcome to the forums,