Microsoft KB Archive/317980

Knowledge Base

FIX: When you use table buffering and insert records, Visual FoxPro may stop responding

Article ID: 317980

Article Last Modified on 4/15/2005

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APPLIES TO

• Microsoft Visual FoxPro 7.0 Professional Edition

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This article was previously published under Q317980

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, click the following article number to view the article in the Microsoft Knowledge Base:

316964 How to Obtain the Latest Visual FoxPro for Windows 7.0 Service Pack

STATUS

Microsoft has confirmed that this is 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.

Keywords: kbbug kbfix kbvfp700sp1fix kbcodesnippet kbdatabase KB317980

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