Problems when switching symbols

[loren325]

When switching symbols, the unsubscribeBars method in the datefeed file is executed after subscribeBars and is delayed by about 10 seconds. How can I make the unsubscribeBars method be executed before subscribeBars?

[danielg-tv]

Hello @loren325 , it's expected for unsubscribeBars() to be called with a delay,
https://www.tradingview.com/charting-library-docs/latest/getting_started/Frequently-Asked-Questions/#:~:text=Why%20is%20unsubscribeBars%20called%20with%20a%20delay%3F
Basically, that delay is to be sure that no subscriptions outside of the chart are linked to the symbol
You might still have the watchlist, possibly in the AM (Account Manager) or elsewhere. The library handles all this internally and automatically calls unsubscribe when it's no longer needed. In most cases, users shouldn't notice this process, and it won't impact the application's performance.
For newer versions of the library, we have introduced resetCache() method, that might help if you want to force realising cached bars - https://www.tradingview.com/charting-library-docs/latest/releases/release-notes/#v29_2-added_resetcache_method

[loren325]

Thanks for your reply. If I want to implement each setSymbol, I can first execute unsubscribeBars to cancel the old subscription, and then execute subscribeBars to subscribe to the new one, how can I achieve it? I am using v28.2.0

[danielg-tv]

You should let the library handle unsubscribing from a symbol. What you can do is to release cached bars when you receive a callback onResetCacheNeededCallback.