>. I might have another
> simple chart running in another tab just to keep another symbol
> database up to date.
There seems to be a very well kept secret about AB that took me over
a year to find out. There is really no need to keep a chart running in another tab
just to keep it's symbol's data updated.
AB will keep collecting and saving data for any symbol once
it had been scanned. There is no need to view it or chart it again for the
entire session.
So when I start AB, I run (with an automation script) AA pointing
to Scan4AutoSave.afl:
Buy=0;Sell=0;
SymbL2 = StrLeft(Name(),2);
if( SymbL2 == "~~" ) // ~~~EQUITY
IS last change this to the LAST symbol in your database
{
AB = CreateObject("Broker.Application");
AB.SaveDatabase();
}
I apply this only to my (less than 20) favorites (i.e. exclude
expired contracts). For safety I run this every 45 min (arbitrary) such that if
AB or the computer hang, I will lose only the last 45 minute of data.
I made a suggestion to make this whole
process transparent since it is way beyond a beginner’s abilities, but, I
guess it is trivial once you know the answer
> I keep 300,000 5 second bar database
If this is the database settings, it is only about 17 days of
data! I do not use backfill at all since I collect tick data in my database. I want
to include the whole 3 month’s futures contract data, so my settings for
the number of bars is 1,000,000.
>OTOH, I could have another
chart running in another tab which just
>pings messages to the main
chart through a static variable to make
>sure it is alive, and alert me
if it has stalled. Thanks for jogging
>that Idea.
Would you publish your solution once you have it worked out?
Joseph Biran
____________________________________________
-----Original Message-----
From: amibroker@xxxxxxxxxxxxxxx [mailto:amibroker@xxxxxxxxxxxxxxx] On Behalf Of
Dennis Brown
Sent: Friday, June 27, 2008 9:12 PM
To: amibroker@xxxxxxxxxxxxxxx
Subject: Re: [amibroker] Re: When AFL just stops updating the chart now and
then...
Dan, my comments are embedded:
On Jun 27, 2008, at 10:23 PM,
monitorit wrote:
> Hi Dennis,
> Perhaps you can help me -
you'd be the first on this problem :(
> The problem I described is
~daily.
I will do my best..
> MY AB workspace displays the
quotes window, 1-2 t&s windows + 5
> symbol-linked chart windows
(1 min, 2 min, 5 min, 15 min and daily).
> Each chart window has 8
sheets - but all these are empty except the
> first sheet with 1-3 panes
each and 1 window has a study on the
> second sheet. Total
time (sum) for the 5 charts via 'display chart
> timing' is ~400 msec. Running
through these charts afterhours is no
> problem (local db is
enabled).. I see all charts windows completed in
> about 4 seconds after
changing symbols.
My charts are as simple as I can
make them. Just one Main chart which
run everything. Can run as
fast as 200ms to as slow as 10s depending
on the trading parameters I am
using and the amount of history and
especially the number of bars I am
displaying. I might have another
simple chart running in another
tab just to keep another symbol
database up to date.
> What do you think are the
best settings for the pref>data
> tab 'default db settings'
in-memory cache size (max symbols), (max
> megabytes) and number of bars
to load... for a 7400 bar, 100 symbol
> db (and perhaps for a longer
db with more symbols). What do these
> fields actually mean/do?
Good questions, wish I knew all
those answers. My settings:
I only run about a dozen symbols.
I keep 300,000 5 second bar
database
Cache max 82 MB.
I load up to 100,000 bars, but
only about 3,000 1 minule bars when
trading.
> I have 4GB (3 GB available in
vista32) and
> no other programs running...
so is it best to use >1000 megabytes?
I have a 2GB virtual XP32 running
only AB. I use all default settings.
> What is number of bars to
load (does db setting overwrite this?)?
I override this in my AFL with
SetBarsRequired()
> DB settings has a 'flush
cache' button. Doesn't seem to do anything
> for me. Does it work
for you?
It would just reload it again if
it were flushed.
> Refresh and refresh all has
no
> effect. If I do a
refresh current sym, I get new data for that sym
> but then no further updates
for any symbol.
Refresh just forces AFL to run one
cycle on the chart.
I use RequestTimedRefresh() to
make my chart refresh all the time even
if not quotes are coming in.
> My db is 7400 1min bars*100
sym... are you working with a similar
> size?
Like I said, 300,000 5 second bars
for just a few symbols.
> BTW, I know what you mean
about getting hypnotized so I get alerted
> to the quote delay with the
following in the 1min chart - you can
> probably get it to work with
shorter periods or make it say something:
>
>
delayedcolor=IIf(TimeNum()<Now(4)-120 OR DateNum()<Now(3),32,16);
> //for time
at bar start-- 32=colorred, 16=colorblack , red if
> last bar start-time is
earlier than 1min20 sec of system time
> //my bar times are at start
of interval so min# could be 101
>
> Plot( C, "Close",
delayedcolor, styleNoTitle | ParamStyle("Style") |
> GetPriceStyle() );
Assuming that it is not the AFL
that is stalled, I could write
something that would monitor how
long since the last quote came in.
However, in my case, I suspect
that the AFL may not be running any
passes when my charts freeze.
OTOH, I could have another chart
running in another tab which just
pings messages to the main chart
through a static variable to make
sure it is alive, and alert me if
it has stalled. Thanks for jogging
that Idea.
Best regards,
Dennis
> Thanks, Dan
>
> --- In
amibroker@xxxxxxxxxxxxxxx, Dennis Brown <see3d@xxx> wrote:
>>
>> Hello,
>>
>> I have something that
happens once every few days with my RT charts.
>>
>> At some point in the day,
the chart stops updating. I also have
>> getRTData() functions in
my AFL that also stop.
>>
>> I don't know if it is the
data feed that stops handing the quotes
> to
>> AB, or if XP is not
giving the data, or if the AFL loop stops
>> running. Everything
looks normal, but I notice that my broker's
>> charts have moved ahead
and my AB charts have stalled (My broker's
>> charts are prone to
stalling in fast markets and my AB charts keep
> on
>> ticking). This can
be disconcerting when you are in a fast trade
> and
>> you go blind without
realizing it.
>>
>> I am using DTN IQFeed,
but the same thing happened with eSignal in
>> previous years. The
data feed plug-in indicates everything is
> green
>> and working.
>>
>> Clicking on the chart
refresh button starts the chart running again.
>>
>> I am usually in a panic
when this happens, so I have not been able
> to
>> properly go through debug
steps to isolate the problem area.
>>
>> So my questions are:
>>
>> 1. Does anyone know
the root cause of this?
>> 2. Is there a way
to detect that the chart has stopped updating
>> (other than by eye)?
>> 3. Is there a way
to automatically jump start the updating again
> when
>> it happens?
>>
>> Thanks for any insights.
>>
>> If nobody can help, I
will ask support.
>>
>> Best regards,
>> Dennis
>>