Batch write to temporary table

[nsitarz]

Is your feature request related to a problem? Please describe. An ETL application I maintain does batch writes to temporary tables in Clickhouse which requires that a batch be bound to the specific connection that created the table. It doesn't seem to be possible to use the new native interface and have such granular control over the batch's connection.

Describe the solution you'd like I'm open to any solution. The most obvious to me would be to export the acquire and release functions as well as the connect struct and it's funcs.

[gingerwizard]

Any reason you can't just use MaxOpenConns=1?

[gingerwizard]

Also we'd strongly advise using temporary tables - I know other ETL tools e.g. dbt clickhouse, does this but its far from recommended practice. The table will be in memory and susceptible to connection interruptions.

[jkaflik]

Related to #772. Should be solved by #855.

[R-omk]

This functionality has become even more necessary since the ability to specify an arbitrary engine for temporary tables (not only ENGINE = Memory) was added.