Fix incremental delete+insert SQL

[ataft]

resolves dbt-labs/dbt-adapters#150

Problem

The delete query for the 'delete+insert' incremental_strategy with 2+ unique_key columns is VERY inefficient. In many cases, it will hang and never return for deleting small amounts of data (<100K rows).

Solution

Improve the query by switching to a much more efficient delete strategy:

delete from table1
where (col1, col2) in (
    select distinct col1, col2 from table1_tmp
)

Checklist

• I have read the contributing guide and understand what's expected of me
• I have run this code in development and it appears to resolve the stated issue
• This PR includes tests, or tests are not required/relevant for this PR
• This PR has no interface changes (e.g. macros, cli, logs, json artifacts, config files, adapter interface, etc) or this PR has already received feedback and approval from Product or DX
• This PR includes type annotations for new and modified functions

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[github-actions]

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[dbeatty10]

Thanks for raising this PR @ataft !

Could you resolve the merge conflict?

[ataft]

Here's the merge conflict message I'm getting:

Oddly, I don't see the global_project directory in the main branch. Not sure what's going on, see here:
https://github.com/dbt-labs/dbt-core/tree/main/core/dbt/include

[colin-rogers-dbt]

Hi @ataft sorry for the confusion but we're in the middle of a large scale refactor of dbt.adapters. Once that has been wrapped up (in the next couple weeks) we will move your PR to the new dbt-adapters repo and review it there.

More info: #9171

[dataders]

hey @ataft thanks for taking the time to open this PR. Since opening, this code now lives in a separate repo: dbt-adapters. A consequence of the decoupling is that PR can't be merged anymore as is, so we're closing it. For more context see #9171.

The linked issue has already been transferred. Please don't hesitate to re-open on the dbt-adapters repo.

[ataft]

All good, just moved the PR over to dbt-labs/dbt-adapters#151