Increase threads for Integration Test suite

[clausherther]

Describe the feature

Currently integration tests run on 1 thread; this causes the integration test models and schema tests to run very slowly, particularly on Snowflake and BigQuery where a higher thread count would speed things up (and potentially save $ on Snowflake compute).
See:

I propose increasing the threads to 4 or even higher, e.g. 8, for Snowflake and BigQuery integration tests.

Who will this benefit?

Anyone submitting PRs and the FA team if this ends up saving Snowflake compute cost.

Are you interested in contributing this feature?

Yes

[clrcrl]

@jtcohen6 — as guardian of the testing warehouses, do you foresee any issues with this? I think it sounds great! I'd also love to figure out if we can have the different warehouse test jobs running in parallel too, which would considerably speed things up :)

[jtcohen6]

do you foresee any issues with this?

nope!

I'd also love to figure out if we can have the different warehouse test jobs running in parallel too, which would considerably speed things up :)

agreed—this is possible by switching the CircleCI config to use workflows instead of jobs. I could open a PR for that (: