Merge pull request #1709 from fishtown-analytics/fix/simplify-snapsho…

…t-check-logic

make snapshot check strategy simpler and still correct

CHANGELOG.md

@@ -22,7 +22,7 @@ This is primarily a bugfix release which contains a few minor improvements too.
  - Add `node.config` and `node.tags` to the `generate_schema_name` and `generate_alias_name` macro context ([#1700](https://github.com/fishtown-analytics/dbt/issues/1700), [#1701](https://github.com/fishtown-analytics/dbt/pull/1701))
 
 ### Fixes:
- - Fix for reused `check_cols` values in snapshots ([#1614](https://github.com/fishtown-analytics/dbt/pull/1614))
+ - Fix for reused `check_cols` values in snapshots ([#1614](https://github.com/fishtown-analytics/dbt/pull/1614), [#1709](https://github.com/fishtown-analytics/dbt/pull/1709))
  - Fix for rendering column descriptions in sources ([#1619](https://github.com/fishtown-analytics/dbt/issues/1619), [#1633](https://github.com/fishtown-analytics/dbt/pull/1633))
  - Fix for `is_incremental()` returning True for models that are not materialized as incremental models ([#1249](https://github.com/fishtown-analytics/dbt/issues/1249), [#1608](https://github.com/fishtown-analytics/dbt/pull/1608))
  - Fix for serialization of BigQuery results which contain nested or repeated records ([#1626](https://github.com/fishtown-analytics/dbt/issues/1626), [#1638](https://github.com/fishtown-analytics/dbt/pull/1638))
@@ -51,7 +51,7 @@ Thanks for your contributions to dbt!
 - [@edmundyan](https://github.com/edmundyan) ([#1663](https://github.com/fishtown-analytics/dbt/pull/1663))
 - [@vitorbaptista](https://github.com/vitorbaptista) ([#1664](https://github.com/fishtown-analytics/dbt/pull/1664))
 - [@sjwhitworth](https://github.com/sjwhitworth) ([#1672](https://github.com/fishtown-analytics/dbt/pull/1672), [#1673](https://github.com/fishtown-analytics/dbt/pull/1673))
-- [@mikaelene](https://github.com/mikaelene) ([#1688](https://github.com/fishtown-analytics/dbt/pull/1688))
+- [@mikaelene](https://github.com/mikaelene) ([#1688](https://github.com/fishtown-analytics/dbt/pull/1688), [#1709](https://github.com/fishtown-analytics/dbt/pull/1709))
 - [@bastienboutonnet](https://github.com/bastienboutonnet) ([#1591](https://github.com/fishtown-analytics/dbt/pull/1591), [#1689](https://github.com/fishtown-analytics/dbt/pull/1689))
 
 

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

@@ -107,19 +107,7 @@
         )
     {%- endset %}
 
-    {% if target_exists %}
-        {% set row_version -%}
-            (
-             select count(*) from {{ snapshotted_rel }}
-             where {{ snapshotted_rel }}.dbt_unique_key = {{ primary_key }}
-            )
-        {%- endset %}
-        {% set scd_id_cols = [primary_key, row_version] + (check_cols | list) %}
-    {% else %}
-        {% set scd_id_cols = [primary_key] + (check_cols | list) %}
-    {% endif %}
-
-    {% set scd_id_expr = snapshot_hash_arguments(scd_id_cols) %}
+    {% set scd_id_expr = snapshot_hash_arguments([primary_key, updated_at]) %}
 
     {% do return({
         "unique_key": primary_key,