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How to have cursors never be sent to disk?
Message
From
22/01/2014 17:07:44
 
 
To
21/01/2014 11:08:26
General information
Forum:
Visual FoxPro
Category:
Coding, syntax & commands
Environment versions
Visual FoxPro:
VFP 9 SP2
OS:
Windows 7
Network:
Windows 2008 Server
Database:
Visual FoxPro
Application:
Desktop
Miscellaneous
Thread ID:
01592171
Message ID:
01592310
Views:
97
Hi Alejandro,

Sure: the task scheduler can be set up through WMI.

As for performance: it depends on the machine and how it's being used. On a VM App server (RDP or ICA) that opens a number of cursors (one of our main forms opens 37 cursors on opening), it's about 40% less time (6.5 seconds to 3.5 seconds, approximately). This makes a huge difference with 20+ users on the machine hitting the same app.

With one user hitting the app, you won't see much difference, provided it's a modern drive with a bit of cache, etc.

hth,

Hank

>Very helpful Hank. Thanks.
>
>Wonder if there is a way to do the ram disk setup with VFP code so that it is transparent to user.
>
>Alex
>
>>Hi Alejandro,
>>
>>we've been telling our users who want to use VM's that the must provide a ramdisk for tmpfiles (which we set in the config file, of course). The reason is that a) we do a lot of queries; and b) VMFS, even in VSphere 5, is slow at big block writes (v5 speeds up small bursts, but doesn't affect the big block writes). We set up 4GB for up to 20 users. For a single user, 500MB seems to be plenty. We do, by default, on app launch delete all tmpfiles files that are not currently locked. A tmpfile not currently in use has no need to exist. :)
>>
>>Here are the directions we give them (minus the Google Site formatting, which didn't paste into the message):
>>
>>Setting Up A Ram Disk
>>
>>Using this link http://forums.guru3d.com/showthread.php?t=356046 use NFTS as the file system type, and use the task scheduler On Startup as the creation method. The reason for this is that a ram disk goes away when the computer shuts down/restarts.
>>
>>Note: on a customer site, it is up to their IT to set this up. Feel free to copy this information to them, leaving out the NAS information.
>>
>>IMDisk can be downloaded from here: http://www.ltr-data.se/opencode.html/#ImDisk
>>
>>hth,
>>
>>Hank
>>
>>
>>
>>>I've noticed files get created in temporary directory when VFP executes a SELECT INTO CURSOR xx.
>>>
>>>Is there a way to keep cursors 100% in memory and never go to disk, even READWRITE cursors? Sort of like the Ramdisk in DOS days.
>>>
>>>TIA,
>>>
>>>Alex
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