[Backport 1.7.latest] Implementation of metadata-based freshness

.changes/unreleased/Features-20231219-120533.yaml

@@ -0,0 +1,6 @@
+kind: Features
+body: Add support for checking table-last-modified by metadata
+time: 2023-12-19T12:05:33.784649-05:00
+custom:
+  Author: mikealfare
+  Issue: "615"

dbt/adapters/redshift/impl.py

@@ -4,6 +4,7 @@
 from dbt.adapters.base import PythonJobHelper
 from dbt.adapters.base.impl import AdapterConfig, ConstraintSupport
 from dbt.adapters.base.meta import available
+from dbt.adapters.capability import Capability, CapabilityDict, CapabilitySupport, Support
 from dbt.adapters.sql import SQLAdapter
 from dbt.contracts.connection import AdapterResponse
 from dbt.contracts.graph.nodes import ConstraintType
@@ -46,6 +47,12 @@ class RedshiftAdapter(SQLAdapter):
         ConstraintType.foreign_key: ConstraintSupport.NOT_ENFORCED,
     }
 
+    _capabilities = CapabilityDict(
+        {
+            Capability.TableLastModifiedMetadata: CapabilitySupport(support=Support.Full),
+        }
+    )
+
     @classmethod
     def date_function(cls):
         return "getdate()"

dbt/include/redshift/macros/metadata/relation_last_modified.sql

@@ -0,0 +1,29 @@
+{% macro redshift__get_relation_last_modified(information_schema, relations) -%}
+
+    {%- call statement('last_modified', fetch_result=True) -%}
+        select
+            ns.nspname as "schema",
+            c.relname as identifier,
+            max(qd.start_time) as last_modified,
+            {{ current_timestamp() }} as snapshotted_at
+        from pg_class c
+        join pg_namespace ns
+            on ns.oid = c.relnamespace
+        join sys_query_detail qd
+            on qd.table_id = c.oid
+        where qd.step_name = 'insert'
+        and (
+            {%- for relation in relations -%}
+                (
+                    upper(ns.nspname) = upper('{{ relation.schema }}')
+                and upper(c.relname) = upper('{{ relation.identifier }}')
+                )
+                {%- if not loop.last %} or {% endif -%}
+            {%- endfor -%}
+        )
+        group by 1, 2, 4
+    {%- endcall -%}
+
+    {{ return(load_result('last_modified')) }}
+
+{% endmacro %}

tests/functional/adapter/sources_freshness_tests/files.py

@@ -0,0 +1,38 @@
+SCHEMA_YML = """version: 2
+sources:
+  - name: test_source
+    freshness:
+      warn_after: {count: 10, period: hour}
+      error_after: {count: 1, period: day}
+    schema: "{{ env_var('DBT_GET_LAST_RELATION_TEST_SCHEMA') }}"
+    tables:
+      - name: test_source_no_last_modified
+      - name: test_source_last_modified
+        loaded_at_field: last_modified
+"""
+
+SEED_TEST_SOURCE_NO_LAST_MODIFIED_CSV = """
+id,name
+1,Martin
+2,Jeter
+3,Ruth
+4,Gehrig
+5,DiMaggio
+6,Torre
+7,Mantle
+8,Berra
+9,Maris
+""".strip()
+
+SEED_TEST_SOURCE_LAST_MODIFIED_CSV = """
+id,name,last_modified
+1,Martin,2023-01-01 00:00:00
+2,Jeter,2023-02-01 00:00:00
+3,Ruth,2023-03-01 00:00:00
+4,Gehrig,2023-04-01 00:00:00
+5,DiMaggio,2023-05-01 00:00:00
+6,Torre,2023-06-01 00:00:00
+7,Mantle,2023-07-01 00:00:00
+8,Berra,2023-08-01 00:00:00
+9,Maris,2023-09-01 00:00:00
+""".strip()

tests/functional/adapter/sources_freshness_tests/test_get_relation_last_modified.py

@@ -0,0 +1,42 @@
+import os
+
+from dbt.tests.util import run_dbt
+import pytest
+
+from tests.functional.adapter.sources_freshness_tests import files
+
+
+class TestGetLastRelationModified:
+    @pytest.fixture(scope="class")
+    def seeds(self):
+        return {
+            "test_source_no_last_modified.csv": files.SEED_TEST_SOURCE_NO_LAST_MODIFIED_CSV,
+            "test_source_last_modified.csv": files.SEED_TEST_SOURCE_LAST_MODIFIED_CSV,
+        }
+
+    @pytest.fixture(scope="class")
+    def models(self):
+        return {"schema.yml": files.SCHEMA_YML}
+
+    @pytest.fixture(scope="class", autouse=True)
+    def setup(self, project):
+        # we need the schema name for the sources section
+        os.environ["DBT_GET_LAST_RELATION_TEST_SCHEMA"] = project.test_schema
+        run_dbt(["seed"])
+        yield
+        del os.environ["DBT_GET_LAST_RELATION_TEST_SCHEMA"]
+
+    @pytest.mark.parametrize(
+        "source,status,expect_pass",
+        [
+            ("test_source.test_source_no_last_modified", "pass", True),
+            ("test_source.test_source_last_modified", "error", False),  # stale
+        ],
+    )
+    def test_get_last_relation_modified(self, project, source, status, expect_pass):
+        results = run_dbt(
+            ["source", "freshness", "--select", f"source:{source}"], expect_pass=expect_pass
+        )
+        assert len(results) == 1
+        result = results[0]
+        assert result.status == status