cesc

What would be the right place to open a sqlite db connection (db_open) without having to open the database connection on each external?

In short, what would be the best way to open a sqlite connection only once and share that database instance between different multiple externals, instead of each external calling db_open?

What would be the right place to open a sqlite db connection (db_open) without having to open the database connection on each external?

In...

c-api-open-sqlite-connection-only-once-and-share-database-instance-across-multiple-externals

You will need to change your external to an extension, which has code that loads when Max starts up prior to instantiation of a given instance.  (It needs to be deployed into the extensions folder instead of externals) Then you can put it in ext_main.

You can see how I've done it in Scheme for Max here: 

https://github.com/iainctduncan/scheme-for-max/blob/master/s4m/s4m.c

I make the s4m-array registry in ext-main so it can be shared among instances.

@Ian thanks, that idea helps, not sure if I will go for it but is good to know, that I could change the external to an extension to execute code on startup.

@11olsen those are interesting idea too. 

(1.) for multiple threads sqlite would have to be compiled with SQLITE_THREADSAFE, not sure if Cycling did that with it's embedded sqlite.  If I understand Max correctly the main thread handles the execution of events, thus unless I create threads manually there should be no need for SQLITE_THREADSAFE. 

I will test how much overhead is to open a db connection per external.

(2.) That's probably the easiest, I would need to share that db connection between different type of externals, but it's ok to have each type of external share one db connection. Thanks!

(3.) Sounds probably what I need but depending on how much overhead is to create a db connection pro external (1.) sounds easier to implement.

Once again thank you both for offering your ideas.

(c-api) open sqlite connection only once and share database instance across multiple externals