Herman, In regards to question #1, I emailed support a week or two ago with the same question (as I noticed that it had no effect in limiting data in a local db). This is how Marcin explained it:
"This setting applies to the databases operated by RT plugin, but not to (local database). If you want to limit the size of the local database - then go to Tools -> Preferences -> Data, then mark "Limit number of saved qutations" (and modify the data somehow, so the changes will be saved and limit applied with the save operation)." - Tim On Thu, Oct 8, 2009 at 9:54 AM, Herman <[email protected]> wrote: > For DB backups I use dated sub-folders in an AmiBrokerBackup folder. I > don't overwrite anything, I just delete a bunch once in awhile. Disk > space is plentiful and cheap but time is not. When backing up and > restoring AB be aware that you can run into problems restoring if you > backup to a different drive letter. > > As someone else mentioned, for processing speed I develop with my large > RT DB set to "Local database", having the data plugin connected really > slows down things. > > There are other factors to consider when working with minute DBs. A > clear understanding of what the DB and Preference settings mean, and how > they should be set is essential. After all these years i am still > struggling with some points, perhaps someone can explain in layman's terms: > > 1) What does "File -> Database Settings -> Number of bars" really mean? > It doesn't seem to set the "limit" for the data base because I can still > have 250000 bars even if it is set to 50,000. If it refers to "Bars > Loaded" why do we have another "Number of Bars to load" in Preferences > -> Data ? When is it enforced, only when the DB is created or can it be > changed for an old DB? Would this corrupt my DB? Would it reduce the DB > in Size? > > 2) Is there an absolute limit to the number of bars loaded? What happens > when you exceed the DB or Preferences setting, would it corrupt the DB? > > 3) How to set the In-Memory Cache size? Do we have to change this each > time we run a different DB? Perhaps someone should design a AmiBroker > Setup calculator :-) one of those panels you enter your system/DB > parameters in and it tells you what settings to use. Volunteers? > > 4) Same question for Max. megabytes... > > When changing these settings, when do they take effect? > > I know there are ways to calculate memory usage but I create a new DB > almost every day, I wish there was a safe default setting (XP 4GB). If > CacheSize * NumberOfBars * 32 cannot exceed the maxMegabytes the user > should be prevented from doing so. Or is it more complicated that that? > > Often when running a portfolio Backtest everything runs fine until at > the very end (after waiting ten minutes) the Backtester gives me an > error. I am pretty sure i am running out of memory, but this is a > technical issue that i shouldn't have to concern myself with. > > herman > > etoketrader wrote: > > touching on the topic of backups, I fully agree with Herman. > > In my nightly schedule I shut down AB and copy the entire folder as > follows: > > > > AB3 -> AB4 > > AB2 -> AB3 > > AB1 -> AB2 > > Live Amimbroker -> AB1 > > > > Sounds like an overkill, but it is not the first time I had to go back > several copies. Corrupt data is not immediately evident in many cases, > especially when dealing with large DB's. > > > > BR, > > eToke > > > > > > > > ------------------------------------ > > > > **** IMPORTANT PLEASE READ **** > > This group is for the discussion between users only. > > This is *NOT* technical support channel. > > > > TO GET TECHNICAL SUPPORT send an e-mail directly to > > SUPPORT {at} amibroker.com > > > > TO SUBMIT SUGGESTIONS please use FEEDBACK CENTER at > > http://www.amibroker.com/feedback/ > > (submissions sent via other channels won't be considered) > > > > For NEW RELEASE ANNOUNCEMENTS and other news always check DEVLOG: > > http://www.amibroker.com/devlog/ > > > > Yahoo! Groups Links > > > > > > > > > > > > > > > ------------------------------------ > > **** IMPORTANT PLEASE READ **** > This group is for the discussion between users only. > This is *NOT* technical support channel. > > TO GET TECHNICAL SUPPORT send an e-mail directly to > SUPPORT {at} amibroker.com > > TO SUBMIT SUGGESTIONS please use FEEDBACK CENTER at > http://www.amibroker.com/feedback/ > (submissions sent via other channels won't be considered) > > For NEW RELEASE ANNOUNCEMENTS and other news always check DEVLOG: > http://www.amibroker.com/devlog/ > > Yahoo! Groups Links > > > >
