Include hard-deletes when making snapshot

CHANGELOG.md

@@ -3,6 +3,10 @@
 ### Features
 - dbt will compare configurations using the un-rendered form of the config block in dbt_project.yml ([#2713](https://github.com/fishtown-analytics/dbt/issues/2713), [#2735](https://github.com/fishtown-analytics/dbt/pull/2735))
 - Added state and defer arguments to the RPC client, matching the CLI ([#2678](https://github.com/fishtown-analytics/dbt/issues/2678), [#2736](https://github.com/fishtown-analytics/dbt/pull/2736))
+- Added ability to snapshot hard-deleted records (opt-in with `invalidate_hard_deletes` config option). ([#249](https://github.com/fishtown-analytics/dbt/issues/249), [#2749](https://github.com/fishtown-analytics/dbt/pull/2749))
+
+Contributors:
+- [@joelluijmes](https://github.com/joelluijmes) ([#2749](https://github.com/fishtown-analytics/dbt/pull/2749))
 
 ## dbt 0.18.0 (September 03, 2020)
 

core/dbt/include/global_project/macros/materializations/snapshot/snapshot.sql

@@ -65,6 +65,16 @@
         from snapshot_query
     ),
 
+    {%- if strategy.invalidate_hard_deletes %}
+    deletes_source_data as (
+
+        select 
+            *,
+            {{ strategy.unique_key }} as dbt_unique_key
+        from snapshot_query
+    ),
+    {% endif %}
+
     insertions as (
 
         select
@@ -99,9 +109,33 @@
         )
     )
 
+    {%- if strategy.invalidate_hard_deletes -%}
+    ,
+
+    deletes as (
+
+        select
+            'delete' as dbt_change_type,
+            source_data.*,
+            {{ snapshot_get_time() }} as dbt_valid_from,
+            {{ snapshot_get_time() }} as dbt_updated_at,
+            {{ snapshot_get_time() }} as dbt_valid_to,
+            snapshotted_data.dbt_scd_id
+
+        from snapshotted_data
+        left join deletes_source_data as source_data on snapshotted_data.dbt_unique_key = source_data.dbt_unique_key
+        where snapshotted_data.dbt_valid_to is null
+        and source_data.dbt_unique_key is null
+    )
+    {%- endif %}
+
     select * from insertions
     union all
     select * from updates
+    {%- if strategy.invalidate_hard_deletes %}
+    union all
+    select * from deletes
+    {%- endif %}
 
 {%- endmacro %}
 

core/dbt/include/global_project/macros/materializations/snapshot/snapshot_merge.sql

@@ -17,6 +17,12 @@
         then update
         set dbt_valid_to = DBT_INTERNAL_SOURCE.dbt_valid_to
 
+    when matched
+     and DBT_INTERNAL_DEST.dbt_valid_to is null
+     and DBT_INTERNAL_SOURCE.dbt_change_type = 'delete'
+        then update
+        set dbt_valid_to = DBT_INTERNAL_SOURCE.dbt_valid_to
+
     when not matched
      and DBT_INTERNAL_SOURCE.dbt_change_type = 'insert'
         then insert ({{ insert_cols_csv }})

core/dbt/include/global_project/macros/materializations/snapshot/strategies.sql

@@ -66,6 +66,7 @@
 {% macro snapshot_timestamp_strategy(node, snapshotted_rel, current_rel, config, target_exists) %}
     {% set primary_key = config['unique_key'] %}
     {% set updated_at = config['updated_at'] %}
+    {% set invalidate_hard_deletes = config['invalidate_hard_deletes'] %}
 
     {#/*
         The snapshot relation might not have an {{ updated_at }} value if the
@@ -86,7 +87,8 @@
         "unique_key": primary_key,
         "updated_at": updated_at,
         "row_changed": row_changed_expr,
-        "scd_id": scd_id_expr
+        "scd_id": scd_id_expr,
+        "invalidate_hard_deletes": invalidate_hard_deletes
     }) %}
 {% endmacro %}
 
@@ -131,6 +133,8 @@
 {% macro snapshot_check_strategy(node, snapshotted_rel, current_rel, config, target_exists) %}
     {% set check_cols_config = config['check_cols'] %}
     {% set primary_key = config['unique_key'] %}
+    {% set invalidate_hard_deletes = config['invalidate_hard_deletes'] %}
+
     {% set select_current_time -%}
         select {{ snapshot_get_time() }} as snapshot_start
     {%- endset %}
@@ -173,6 +177,7 @@
         "unique_key": primary_key,
         "updated_at": updated_at,
         "row_changed": row_changed_expr,
-        "scd_id": scd_id_expr
+        "scd_id": scd_id_expr,
+        "invalidate_hard_deletes": invalidate_hard_deletes
     }) %}
 {% endmacro %}

plugins/postgres/dbt/include/postgres/macros/materializations/snapshot_merge.sql

@@ -9,6 +9,13 @@
       and DBT_INTERNAL_SOURCE.dbt_change_type::text = 'update'::text
       and {{ target }}.dbt_valid_to is null;
 
+    update {{ target }}
+    set dbt_valid_to = DBT_INTERNAL_SOURCE.dbt_valid_to
+    from {{ source }} as DBT_INTERNAL_SOURCE
+    where DBT_INTERNAL_SOURCE.dbt_scd_id::text = {{ target }}.dbt_scd_id::text
+      and DBT_INTERNAL_SOURCE.dbt_change_type::text = 'delete'::text
+      and {{ target }}.dbt_valid_to is null;
+
     insert into {{ target }} ({{ insert_cols_csv }})
     select {% for column in insert_cols -%}
         DBT_INTERNAL_SOURCE.{{ column }} {%- if not loop.last %}, {%- endif %}

test/integration/004_simple_snapshot_test/test-snapshots-pg/snapshot.sql

@@ -9,6 +9,11 @@
             updated_at='updated_at',
         )
     }}
+
+    {% if var('invalidate_hard_deletes', 'false') | as_bool %}
+        {{ config(invalidate_hard_deletes=True) }}
+    {% endif %}
+
     select * from {{target.database}}.{{target.schema}}.seed
 
 {% endsnapshot %}

test/integration/004_simple_snapshot_test/test_simple_snapshot.py

@@ -1,4 +1,5 @@
 from test.integration.base import DBTIntegrationTest, use_profile
+from datetime import datetime
 import dbt.exceptions
 
 
@@ -754,3 +755,44 @@ def test__postgres__changing_strategy(self):
 
         results = self.run_dbt(['test'])
         self.assertEqual(len(results), 1)
+
+
+class TestSnapshotHardDelete(BaseSimpleSnapshotTest):
+
+    @property
+    def project_config(self):
+        return {
+            'config-version': 2,
+            "data-paths": ['data'],
+            "snapshot-paths": ['test-snapshots-pg'],
+            'macro-paths': ['macros'],
+        }
+
+    @use_profile('postgres')
+    def test__postgres__snapshot_hard_delete(self):
+        # This test uses the same seed data, containing 20 records of which we hard delete the last 10.
+        # These deleted records set the dbt_valid_to to time the snapshot was ran.
+
+        self.dbt_run_seed_snapshot()
+        self.assert_expected()
+
+        database = self.default_database
+        self.run_sql(
+            'delete from {}.{}.seed where id >= 10;'.format(database, self.unique_schema())
+        )
+
+        begin_snapshot_datetime = datetime.utcnow()
+
+        results = self.run_dbt(['snapshot', '--vars', '{invalidate_hard_deletes: true}'])
+        self.assertEqual(len(results), self.NUM_SNAPSHOT_MODELS)
+
+        results = self.run_sql(
+            'select * from {}.{}.snapshot_actual'.format(database, self.unique_schema()),
+            fetch='all'
+        )
+
+        self.assertEqual(len(results), 20)
+        for result in results[10:]:
+            # result is a tuple, the dbt_valid_to column is the latest
+            self.assertIsInstance(result[-1], datetime)
+            self.assertGreaterEqual(result[-1], begin_snapshot_datetime)

test/rpc/test_snapshots.py

@@ -19,7 +19,7 @@
             updated_at='updated_at',
         )
     }}
-    select 1 as id, '2019-10-31 23:59:40' as updated_at
+    select 1 as id, cast('2019-10-31 23:59:40' as timestamp) as updated_at
 
 {% endsnapshot %}
 '''
@@ -36,7 +36,7 @@
             updated_at='updated_at',
         )
     }}
-    select 2 as id, '2019-10-31 23:59:40' as updated_at
+    select 2 as id, cast('2019-10-31 23:59:40' as timestamp) as updated_at
 
 {% endsnapshot %}
 '''
@@ -169,4 +169,4 @@ def test_rpc_snapshot_state(
         results = querier.async_wait_for_result(
             querier.snapshot(state='./state', select=['state:modified']),
         )
-        assert len(results['results']) == 0
+        assert len(results['results']) == 0