Hi <@U0EC2UPDF> - we upgraded from exposed 9.0.1 t...

# exposed

[oshai]

Hi @tapac - we upgraded from exposed 9.0.1 to 10.0.2 and I think there is a memory leak. for example with 9.0.1 we have one instance of org.jetbrains.exposed.sql.vendors.MysqlDialect and with 10.0.2 we had 277725 instances when I took a memory dump. So it is either a leak or we are not using exposed as we should with the new version. Do you have an idea what can go wrong?

[tapac]

Hi, the only thing what comes to mind is that you call Database.connect() before every transaction.
It's unnecessary, you should call connect only once per different database.

[oshai]

ok, and can it be disconnected? In version 9.0.1 we didn't have that issue so we were just calling it on every transaction like you said

[tapac]

Not so far time ago Dialects were an objects, i.e. singletons. But as Dialect can have it's own state (dialect metadata depends on concrete database version you connect), this part was reworked and now you achieve new Dialect instance for each Database.

So you may work with two different MySQL databases concurrently

[oshai]

awesome, we will work on it and see if it is ok

[tapac]

JFYI https://github.com/JetBrains/Exposed/wiki/Transactions#working-with-a-multiple-databases

[oshai]

we probably should write somewhere that now you should only connect once to a database (this was not the guidance before)

[tapac]

We use something like :

object Settings {
   val db by lazy { 
       Database.connect("")
   }
}

[oshai]

we will wrap database with spring bean

[oshai]

I will add your example to docs

[oshai]

added example to docs and did some more alterations to relevant pages: https://github.com/JetBrains/Exposed/wiki/DataBase-and-DataSource