Add merge incremental strategy

.changes/unreleased/Features-20230211-163236.yaml

@@ -0,0 +1,6 @@
+kind: Features
+body: Add merge as valid incremental strategy for postgres
+time: 2023-02-11T16:32:36.2260502+01:00
+custom:
+  Author: rainermensing
+  Issue: "1880"

.pre-commit-config.yaml

@@ -1,63 +1,63 @@
-# Configuration for pre-commit hooks (see https://pre-commit.com/).
-# Eventually the hooks described here will be run as tests before merging each PR.
-
-# TODO: remove global exclusion of tests when testing overhaul is complete
-exclude: ^(test/|core/dbt/docs/build/)
-
-# Force all unspecified python hooks to run python 3.8
-default_language_version:
-  python: python3
-
-repos:
-- repo: https://github.com/pre-commit/pre-commit-hooks
-  rev: v3.2.0
-  hooks:
-  - id: check-yaml
-    args: [--unsafe]
-  - id: check-json
-  - id: end-of-file-fixer
-  - id: trailing-whitespace
-    exclude_types:
-      - "markdown"
-  - id: check-case-conflict
-- repo: https://github.com/psf/black
-  rev: 22.3.0
-  hooks:
-  - id: black
-  - id: black
-    alias: black-check
-    stages: [manual]
-    args:
-    - "--check"
-    - "--diff"
-- repo: https://github.com/pycqa/flake8
-  rev: 4.0.1
-  hooks:
-  - id: flake8
-  - id: flake8
-    alias: flake8-check
-    stages: [manual]
-- repo: https://github.com/pre-commit/mirrors-mypy
-  rev: v0.942
-  hooks:
-  - id: mypy
-    # N.B.: Mypy is... a bit fragile.
-    #
-    # By using `language: system` we run this hook in the local
-    # environment instead of a pre-commit isolated one.  This is needed
-    # to ensure mypy correctly parses the project.
-
-    # It may cause trouble
-    # in that it adds environmental variables out of our control to the
-    # mix.  Unfortunately, there's nothing we can do about per pre-commit's
-    # author.
-    # See https://github.com/pre-commit/pre-commit/issues/730 for details.
-    args: [--show-error-codes]
-    files: ^core/dbt/
-    language: system
-  - id: mypy
-    alias: mypy-check
-    stages: [manual]
-    args: [--show-error-codes, --pretty]
-    files: ^core/dbt/
-    language: system
+# Configuration for pre-commit hooks (see https://pre-commit.com/).
+# Eventually the hooks described here will be run as tests before merging each PR.
+
+# TODO: remove global exclusion of tests when testing overhaul is complete
+exclude: ^(test/|core/dbt/docs/build/)
+
+# Force all unspecified python hooks to run python 3.8
+default_language_version:
+  python: python3
+
+repos:
+- repo: https://github.com/pre-commit/pre-commit-hooks
+  rev: v3.2.0
+  hooks:
+  - id: check-yaml
+    args: [--unsafe]
+  - id: check-json
+  - id: end-of-file-fixer
+  - id: trailing-whitespace
+    exclude_types:
+      - "markdown"
+  - id: check-case-conflict
+- repo: https://github.com/psf/black
+  rev: 22.3.0
+  hooks:
+  - id: black
+  - id: black
+    alias: black-check
+    stages: [manual]
+    args:
+    - "--check"
+    - "--diff"
+- repo: https://github.com/pycqa/flake8
+  rev: 4.0.1
+  hooks:
+  - id: flake8
+  - id: flake8
+    alias: flake8-check
+    stages: [manual]
+- repo: https://github.com/pre-commit/mirrors-mypy
+  rev: v0.942
+  hooks:
+  - id: mypy
+    # N.B.: Mypy is... a bit fragile.
+    #
+    # By using `language: system` we run this hook in the local
+    # environment instead of a pre-commit isolated one.  This is needed
+    # to ensure mypy correctly parses the project.
+
+    # It may cause trouble
+    # in that it adds environmental variables out of our control to the
+    # mix.  Unfortunately, there's nothing we can do about per pre-commit's
+    # author.
+    # See https://github.com/pre-commit/pre-commit/issues/730 for details.
+    args: [--show-error-codes]
+    files: ^core/dbt/
+    language: system
+  - id: mypy
+    alias: mypy-check
+    stages: [manual]
+    args: [--show-error-codes, --pretty]
+    files: ^core/dbt/
+    language: system

plugins/postgres/dbt/adapters/postgres/impl.py

@@ -130,4 +130,4 @@ def valid_incremental_strategies(self):
         """The set of standard builtin strategies which this adapter supports out-of-the-box.
         Not used to validate custom strategies defined by end users.
         """
-        return ["append", "delete+insert"]
+        return ["append", "delete+insert", "merge"]