DOCUMENT:Q317980  30-MAR-2002  [foxpro]
TITLE   :FIX: Inserting Records with Buffering can Cause VFP to Hang
PRODUCT :Microsoft FoxPro
PROD/VER::7.0
OPER/SYS:
KEYWORDS:kbDatabase KbDBFDBC kbGrpDSFox kbDSupport kbCodeSnippet kbvfp700 _IK283 kbVFP700sp1fix

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The information in this article applies to:

 - Microsoft Visual FoxPro for Windows, version 7.0 
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SYMPTOMS
========

If you use optimistic table buffering, and you insert a large number of records
that use transactions into the table, Visual FoxPro may stop responding.

RESOLUTION
==========

To resolve this problem, obtain the latest service pack for Visual FoxPro for
Windows 7.0. For additional information, please see the following article in the
Microsoft Knowledge Base:

   Q316964 How to Obtain the Latest Visual FoxPro for Windows 7.0 Service Pack

STATUS
======

Microsoft has confirmed this to be a problem in Microsoft Visual FoxPro for
Windows 7.0.

This problem was first corrected in Visual FoxPro for Windows 7.0 Service Pack 1.

MORE INFORMATION
================

Steps To Reproduce Behavior
---------------------------

1. Paste the following code in a program (.prg) file, and then run the program
   from the Command window:

   #DEFINE NUMRECORDS 600

   LOCAL i, n,nRecNo

   CLEAR ALL
   CLEAR
   SET TALK OFF
   SET SAFETY OFF
   SYS(3050,1,100)
   SYS(3050,2,100)

   * Close any open databases.
   CLOSE DATABASES ALL
   CREATE DATABASE Test

   ERASE Test.dbf
   CREATE TABLE Testx (name c(100),aa c(100))
   CREATE SQL VIEW Test AS SELECT * FROM Testx
   USE Test
   REQUERY()
   SET MULTILOCKS ON
   INDEX ON name TAG name
   CURSORSETPROP("buffering",5)

   * Add 600 records to the table.
   FOR i = 1 TO NUMRECORDS
     INSERT INTO Test (name) VALUES (TRANSFORM(i))
   ENDFOR

   * Generate a random number between 0 and 1.
   RAND(1)

   FOR i = 1 to RECCOUNT()
      n=INT(RAND()*RECCOUNT()+1)
      GOTO n
      REPLACE name WITH TRANSFORM(RECCOUNT()-i)

      * Display the records at 100, 200, and so on.
      IF MOD(i,100) = 0
      ? i
      ENDIF
   ENDFOR

   * Insert another record in the table.
   BEGIN TRANSACTION 
     INSERT INTO Test (name) VALUES ("test")
   END TRANSACTION

   *Locate the first logical record in the table.
   LOCATE
   nRecNo = 0
   * Run through all of the records in the table.
   SCAN
      * Display the record number and the contents of the name field. 
      * The record number is negative because the record has been appended in 
      * a buffer. FoxPro will lock up on record number 573. It happens when it 
      * is scanning through records after they have been inserted.
      ? RECNO(), ALLTRIM(name)
      nRecNo = nRecNo + 1
   ENDSCAN
   * Display final stats
   ? nRecNo, NUMRECORDS

Note that Visual FoxPro stops responding while the program is running.

2. Press CTRL+ALT+DELETE to open Windows Task Manager, and then click End Task
   to close Visual FoxPro.

Additional query words:

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Keywords          : kbDatabase KbDBFDBC kbGrpDSFox kbDSupport kbCodeSnippet kbvfp700 _IK283 kbVFP700sp1fix 
Technology        : kbVFPsearch kbAudDeveloper kbVFP700
Version           : :7.0
Issue type        : kbbug
Solution Type     : kbfix

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Copyright Microsoft Corporation 2002.