Deletion of oldest data in a DB


I have a Tick DB and set the limit to 300K bars. I get data from a data source through a plugin. Earlier, when this limit was reached, I observed that the oldest data was automatically removed from DB and new data was filled in. Please correct if my understanding is not correct.
If my understanding is correct, I am fine with this deletion of old data. What I would like to understand - is this controlled through some setting in Amibroker or through the plugin?
Currently, I am experiencing that once the limit is reached, oldest data is not automatically deleted and new data is not updated. Data update gets stuck once the limit is reached and no new data is added. If I increase the limit to 400K, data starts getting updated again.

As documented in the manual, the limit is for plugin-driven sources only
If your data are “stuck” and new data are not added you are using 3rd party plugin that is written incorrectly. Your plugin supplier needs to fix their plugin.

@Tomasz, thanks for the reply. Prior to my to writing above message, I had already referred to the URL you mentioned. Yes, the limit is for plugin-driven sources only.

Just, wish to confirm my understanding.
The plugin is expected to remove oldest data automatically once limit is reached.
If the plugin is written correctly, the oldest data is automatically removed by Amibroker and new data is added.


Read the docs
and ADK.

When plugin is used, AmiBroker does NOT control the data - the PLUGIN controls entire quote array. It should be written the way as presented in ADK (development kit). There are source codes for plugins showing precisely how to write them correctly. The plugin is supposed to fill Quote Array with MOST RECENT QUOTES. Period. This means that LAST BAR in quote array should ALWAYS represent MOST RECENT QUOTE.
It is PLUGIN responsibility.
If you have more data than array size you should STILL FILL THE LAST BARs with most recent quotes and that means that you DISCARD oldest quotes (not fitting in the array) IN THE PLUGIN.