Test times out - Foreign Key constraint test on Postgres tables with 800k+ rows about dbt_constraints

[sfc-gh-dflippo]

I should first point out that you can use the relationship test to create all your fk constraints unless you need to create a compound constraint with multiple columns. That is the main advantage over the out of the box test. I am traveling home from a vacation but I will review the links you provided on the outer join this weekend. Snowflake is ok with that SQL to test a fk constraint in an outer join.

[sfc-gh-dflippo]

I am about to merge my fix into main. Based on your information, I looked into the very latest SQL for the default relationship test and exactly as you say, it uses a left join. I happen to know that Snowflake's query optimizer rewrites most IN / EXISTS conditions to perform a LEFT JOIN operation and I believe it makes sense for this to be the default SQL for foreign_key since it is the default for the relationship test.

In the process of my testing these changes on PostgreSQL I also identified an edge case involving constraints on seeds. During incremental runs dbt truncates such tables and this truncate will fail on PostgreSQL if there are any FK or PK/UK referenced by FK. I have added logic to drop constraints on tables before truncating.

[skwaugh]

Thank you Dan! Good to know re: single- and multi-column FK constraints. This package has seriously improved my quality of life