Preferences Preferences Preferences

[mastermind007]

Hello

In Amibroker Tools->Preferences->Data tab reveals a setting that is very useful to manage the overall database.

There is a check box that reads "Limit number of saved quotations". If you turn this param on and provide a valid number, say 25000, in the text box following it, Amibroker will ensure that saved bar counts any symbol in the database will not exceed 25000

This is a great to manage the size of symbol and very handy for saving NSE Intraday data. 25000 bars of 1 minutes is approximately 66 days (or 3 months) of Intraday data.

However, if you regularly back test, you need bigger intraday data set (1 year, 2 year, 3 year). Naturally, one would create a different intraday database and save it there but this preference which is handy in one scenario causes problem in another.

So, how does one restrict the bar count in one locally saved database while giving free rein to another?

 

[alokdaga]

database setting->Number of bars
Can this help? Pl see

 

[wisp]

Hello

In Amibroker Tools->Preferences->Data tab reveals a setting that is very useful to manage the overall database.



There is a check box that reads "Limit number of saved quotations". If you turn this param on and provide a valid number, say 25000, in the text box following it, Amibroker will ensure that saved bar counts any symbol in the database will not exceed 25000

This is a great to manage the size of symbol and very handy for saving NSE Intraday data. 25000 bars of 1 minutes is approximately 66 days (or 3 months) of Intraday data.

However, if you regularly back test, you need bigger intraday data set (1 year, 2 year, 3 year). Naturally, one would create a different intraday database and save it there but this preference which is handy in one scenario causes problem in another.

So, how does one restrict the bar count in one locally saved database while giving free rein to another?

File/Database Settings This setting is unique for each database

 

[mastermind007]

File/Database Settings This setting is unique for each database

alokdaga and wisp
Yes, the setting that both of you hinted is indeed unique for each individual database but it is all together irrelevant for automatically restricting the size of the locally stored database.

Kindly see the help page on "Database settings" and locate the paragraph that reads.

Number of bars to load - defines how many bars should be loaded from external data source and kept in AmiBroker. Examples: 10-years EOD: 2600, 60-days intraday 1-minute: 30000 (approx). This setting has no effect if data source is set to (local).

The last line (shown in red) of the above para makes it clear that the setting is irrelevant for local databases.

Incidentally, I do use that setting for my EOD database that is stored in metastock format and retrieved via a plugin and this setting will never delete any past historical data. External database may hold lot more data than what will get loaded in Amibroker.

 

[wisp]

alokdaga and wisp
Yes, the setting that both of you hinted is indeed unique for each individual database but it is all together irrelevant for automatically restricting the size of the locally stored database.

Kindly see the help page on "Database settings" and locate the paragraph that reads.



The last line (shown in red) of the above para makes it clear that the setting is irrelevant for local databases.

Incidentally, I do use that setting for my EOD database that is stored in metastock format and retrieved via a plugin and this setting will never delete any past historical data. External database may hold lot more data than what will get loaded in Amibroker.

So how about if you unchecked the limit in preferences and limit your database sizes individual through database/settings, that should solve the problem, right?

 

[mastermind007]

So how about if you unchecked the limit in preferences and limit your database sizes individual through database/settings, that should solve the problem, right?

That will not remove the past data.

 

[wisp]

That will not remove the past data.

Export data, delete unnecessary data from text file, create new db and import.

 

[mastermind007]

Export data, delete unnecessary data from text file, create new db and import.

That one little check box did the job of deleting past data (assuming it was unnecessary) but unfortunately I've confirmed from multiple sources that it is indeed a global setting.

So, Yes, the solution you've suggested is in the general direction that I realize I will have to go through and it will take at least one whole weekend (or maybe more).

As of now, my general plan is to export all the data out of amibroker into csv, create a metastock database out of it and then use metastock plugin to bring it back into amibroker. With some luck, I may able to have 2-3 years of 1 min data loading after all for back testing. I had done that a while ago with my EOD database.


I had resorted to deleting data only because amibroker speed was issue with large data set.

 

[wisp]

That one little check box did the job of deleting past data (assuming it was unnecessary) but unfortunately I've confirmed from multiple sources that it is indeed a global setting.

So, Yes, the solution you've suggested is in the general direction that I realize I will have to go through and it will take at least one whole weekend (or maybe more).

As of now, my general plan is to export all the data out of amibroker into csv, create a metastock database out of it and then use metastock plugin to bring it back into amibroker. With some luck, I may able to have 2-3 years of 1 min data loading after all for back testing. I had done that a while ago with my EOD database.


I had resorted to deleting data only because amibroker speed was issue with large data set.

Why would it take you one whole weekend or more? How many scrips?

 

[mastermind007]

Why would it take you one whole weekend or more? How many scrips?

Approx 500; F & O + Cash + Options. Quite a few of them are duplicates created when names change. All that cleanup also needs to be done.