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Sudden slow database access
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13/01/2015 16:43:45
 
 
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Information générale
Forum:
Visual FoxPro
Catégorie:
Base de données, Tables, Vues, Index et syntaxe SQL
Titre:
Sudden slow database access
Versions des environnements
Visual FoxPro:
VFP 9 SP2
OS:
Windows 7
Network:
Windows XP
Database:
Visual FoxPro
Application:
Desktop
Divers
Thread ID:
01613560
Message ID:
01613560
Vues:
93
Hi All,
VFP 9/SP2 app using VFP for the database engine and running the executable from the workstations. Workstations have a local app folder with a mapped drive to a shared folder on the server where the data resides:

Server is XP Pro/SP3
Workstations are XP and Win 7 Pro.
No windows updates on the workstations or the server for months prior to 12/31/2014.
No change to my app or the database since September 2014.
Plenty of disk space on server and on workstations.

ISSUE: As of 12/31/2014, my app is experiencing horribly slow access to the data.

Live environment (workstation’s X drive):
As described above

Test environment (workstation’s Y drive):
Copy of live environment to a different folder on the same HDD on the same server and also shared.
Map an additional drive letter to the test environment on the server.

Both environments are the same with the same data.
Bill_Codes table contains 12 records.
Bill_Code_Hist contains 54K records.

From a workstation using foxpro command window:
Set exclusive off
open database X:\data\inmatetrustfund.dbc
select * from inmatetrustfund!bill_code_hist inner join inmatetrustfund!bill_codes on bill_code_hist.cbill_codes_id=bill_codes.cid into cursor lcresult
-- takes 101.48 seconds --
close databases all
open database Y:\data\inmatetrustfund.dbc
select * from inmatetrustfund!bill_code_hist inner join inmatetrustfund!bill_codes on bill_code_hist.cbill_codes_id=bill_codes.cid into cursor lcresult
-- takes 5.34 seconds --

The database has approx. 100 tables. I get similar results regardless which table(s) are queried.

I should mention, running my application has similar results meaning it takes 20 times longer to do operation A in the live environment versus the test environment.

I also conducted a test copying large files. There is no difference simply copying or moving files between the workstation and the server regardless whether performed on the X or Y drives.

Perhaps the most important fact: As long as only 1 workstation has the database open, there is NO difference between the live and test environments. It is ONLY when another user opens the same database as I am testing against, that the slowness occurs.

This app has been running well for over 10 years. This only started 12/31/2014 and has been persistent since.

I have of course reindexed all tables and have looked for any sign of bad data and can find none.

Thanks for any help,

John Cook
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