Record locking

[GCC Consulting]

We all know that after doing a protected lookup using write filename should
unlock the record to which the lookup was done.

System:
filePro native 5.0.11
Server Dell with 1GB RAM, mirrored 18K RPM drives, Windows server 2003, network
3com Hub 100Mbs.
Workstations: various make clones all running Windows XP pro 900+ GHz to 2+ GHZ.

No internet connections - no service paks or updates applied.

I recently completed an upgrade of their order entry system including a
procedure for getting the next available order number from a master file.  A
procedure most of us use.

Problem arose in that the master file record was not being unlocked quickly
enough causing no number to be retrieved or getting an error message that the
record was locked by another process.

@wlf1 if: 1 = ""
    then: GOTO get_num
      if:
    then: "other code"
 ..........
10 Get_num if:
      then: rn(8,.0)="1"
11	  if:
       then: lookup emm = em_mast  r=rn    -np
12	  if:	 not emm
       then: ERRORBOX "Master File Not Found";EXIT
13	  if:
	 then: po_num=emm(10);GOSUB chk_num			(chk_num does a
lookup to the current file to insure that
14 	  if:								(this #
hasn't been used and some other checks
	 then: purchase_order_number=po_num	
15	  if:
	 then: emm(10)= purchase_order_number+"1";wrtie emm
16	  if:
	 then: created_by=getenv("username")
17	  if:
	 then: SHOW "";display;end				'move to store #
field

After having a problem with this code failing to work properly, I ran some
tests.

On the serve I have both the production system and a development system.  I ran
the following test using the development system only.

1. Opened a work session to the order entry module
2. Opened another session to display the master file record 1 with the next
order #.
3. Went into add new orders from the order menu
	a. Pressed enter from field 1, the first field entered, got a new order
#
	b. Cursor in store # field, changed to master file session and pressed
"X" to exit record.
	   Received a message that the record was locked by another process.
4. Returned to order entry screen and entered a store # and verified the proper
store.
5. Repeated step 3 with the same results
6. Returned to order entry session and placed a quantity in the quantity field
and pressed <enter>. This placed the cursor in the item # field.
7. Repeat step 3- this time the record was unlocked and I was able to exit to
the menu.
  	 
Change the posting line to:
15	  if:
	 then: emm(10)= purchase_order_number+"1";write emm;sync emm

Repeated the above steps with the same results.

Changed the line again:
15	  if:
	 then: emm(10)= purchase_order_number+"1";wrtie emm;sync emm;close emm

Repeated above steps, this time the record was unlocked right away.

I added the code the yesterday and since then there have been no problems.
However, one never knows.

There is some additional code for insuring (or at least trying to insure) that
no order number is duplicated and that the correct "next Order #" is used.

Closing the master file doesn't cause any problems as most of the time is spent
entering order details which can take from 1 to 10 minutes or more depending on
the number of items being ordered.  

I mentioned this problem in the "chat room" and Nancy advised that she had seen
a similar problem on Novel.  But this proved to be a write cash problem and was
solved by using a short sleep before moving on.

This didn't seem to be my problem as I sat in the store # field for a few
seconds before switching sessions and testing the exit from the master file.

Has anyone else, besides Nancy, seen this problem?

Richard Kreiss
GCC Consulting