Basestation keeps freezing

[glenn]

Hi,
Noticed this morning that every 3 or 4 minutes basestation freezes for 2-5 seconds.
Looked in the debug tool and this is listing every time it happens eg.
2010/03/09: 13.09.03.076: Locked for 00.00.04.
Although this is the first time i have ever looked at debug in the couple of years ive had my sbs so i don't really no if this is nomal or not.Any ideas whats going on? thanks.
Glenn.

[bones]

Are you using many other applications that access the SQB database?

[glenn]

Are you using many other applications that access the SQB database?

Just active display.

[bones]

I assume that to DB gets locked when BS is writing to it - this would avoid confliction with other programs trying to do the same. What I've not understood is why the lock activity varies - sometimes I see my DB locked every 20 seconds or so and sometimes it won't be touched for a few hours.

Today I've had BS running since 0400 and have had just one lock for two seconds at 1530. Other days I can get a pageful of locks showing in debug over an hour or two. I can't explain the variation in activity.

[acarslogger]

Hi all,

I appear to get a lock debug message when I do a Refresh - either using Basestation menu | Aircraft | Refresh DB Data for all Data , or F5.
I assume Basestation takes out an exclusve lock on the database while doing this refresh -it must be quite intensive reselecting the aircraft details for ALL aircraft and redisplaying in the Aircraft List and the Radar Screen.

Am I correct in thinking that AD (and FD ?) can programmatically perform a Refresh every so often ?

Would this account for some or all of the locks ?

Regards
Stuart

[glenn]

Cheers Bones,
Paused active display for 15 mins and did'nt get a single lock,restarted AD and got locks straight away.
So nothing too much to worry about then,perhaps it won't do it tomorrow then!?
Glenn.

[bones]

I also run AD but had no locks other than the one mentioned. Howevere when I started working with data in AD things changed and I had 9 reported locks in 19 minutes. Once AD was running free again the locks stopped.

[glenn]

Morning,
Appears to be worse today,locking nearly every minute for 4 or 5 seconds.
Is there something i should be purging or deleting in AD thats slowing things up?
Ive also always had 'windows virtual memory too low' warning pop up,and says windows is increasing virtual memory,
would this have anything to do with it?
Glenn.

[cessna24v]

Glenn,

Firstly, DB locks are inevitable when you have more than one program accessing the same DB. The SQLite locking process is designed specifically to cater for this situation and others (eg where programs have multiple users), so in general terms is nothing to worry about.
SBSPopulate was built with additional processing to minimise problems in conjunction with the Kinetic Basestation programmer at the time (Will). AD uses the same logic which has proved very effective over the last 4 years.

Now the problem you reported in your first post looks very likely to be caused by a Basestation refresh (F5). Depending on how many aircraft Basestation is handling at that time, the Radar may well 'freeze' for a number of seconds. The assumption is that the program is single threading for this operation and the re-read of all its aircraft takes precedence over the screen repaints.

Now AD performs this function automatically for you to allow the display of data not available in Basestation (eg Routes). The Basestation refresh takes place while AD is in REFRESHING mode. This mode is triggered by the values you have set in your settings. If you look at Settings>>Set Display Formats>>Active, you will see an entry called Refresh Interval. This is set to 4 by default but you can change this. The number entered corresponds roughly to the number of new flights received since the last REFRESHING cycle. The lower the number, the more often the AD REFRESHING cycle and thus also the Basestation refresh occur.
The frequency with which AD thus triggers a Basestation refresh and thus an apparent Radar 'freeze' thus depends on the value you have set in the AD refresh interval AND the traffic which your SBS is receiving at the time.
One thing you shouldn't do in your situation is set the Refresh Interval to 1, especially if you are in a high traffic density area. This will force too many Basestation refreshes.

If you study the CPU (and memory usage) via your PC Task Manager, you should see that when AD is in REAL TIME mode, it chugs along at a fairly low level. This is mainly because it 'sleeps' a lot in this state. However when it is in CATCHING UP mode, usage will spike because it is doing a lot of intensive work and I/O. The same applies at startup where you probably notice a delay after you click start. At this point it is also working very hard, but that is what computers are for

Reading further through the thread it would appear you also have PC memory constraints if you keep getting those messages. I would increase your virtual memory initially but also take a close look at your memory usage. You may well benefit from adding some real memory. This will probably speed up all your PC operations if only because you won't need so much virtual memory for 'swapping'.

Absorb the above and see if your experiences match.
Gary

[glenn]

Gary,
Thankyou very much for your very informative reply,just a couple of dumb questions
How do i increase memory and virtual memory?
And where do i find task manager?
Thanks Glenn.

[bones]

How do i increase memory and virtual memory?

Buy the first. Adjust the second - but this depends on your OS.

And where do i find task manager?

Right click the Taskbar.

[glenn]

Cheers Bones,
OS is windows xp.
Glenn.

[bones]

OK. Vista here so I hope an XP user can jump in.

[KeithH]

OK. Vista here so I hope an XP user can jump in.

You adjust Virtual Memory by seleecting .....

Control Panel
-> System
->Advanced
-> Performance
-> Settings
-> Advanced
-> Virtual Memory

By default it is probably set and "System Managed size" but you can increase decrease by entering figures in the "custom size fields".

Usually the default is OK. So how much RAM do you have.

Keith

EDIT

Task manager is found by right clicking the task bar and selecting it from the list

[glenn]

Cheers KeithH,
Have increased virtual memory,have 26.9GB free space.
Thanks Glenn.