Feat!: Skip model evaluation if upstream external model(s) have not changed

sqlmesh/core/context.py

@@ -274,6 +274,7 @@ def __init__(
         deployability_index: t.Optional[DeployabilityIndex] = None,
         default_dialect: t.Optional[str] = None,
         default_catalog: t.Optional[str] = None,
+        is_restatement: t.Optional[bool] = None,
         variables: t.Optional[t.Dict[str, t.Any]] = None,
         blueprint_variables: t.Optional[t.Dict[str, t.Any]] = None,
     ):
@@ -284,6 +285,7 @@ def __init__(
         self._default_dialect = default_dialect
         self._variables = variables or {}
         self._blueprint_variables = blueprint_variables or {}
+        self._is_restatement = is_restatement
 
     @property
     def default_dialect(self) -> t.Optional[str]:
@@ -308,6 +310,10 @@ def gateway(self) -> t.Optional[str]:
         """Returns the gateway name."""
         return self.var(c.GATEWAY)
 
+    @property
+    def is_restatement(self) -> t.Optional[bool]:
+        return self._is_restatement
+
     def var(self, var_name: str, default: t.Optional[t.Any] = None) -> t.Optional[t.Any]:
         """Returns a variable value."""
         return self._variables.get(var_name.lower(), default)
@@ -328,6 +334,7 @@ def with_variables(
             self.deployability_index,
             self._default_dialect,
             self._default_catalog,
+            self._is_restatement,
             variables=variables,
             blueprint_variables=blueprint_variables,
         )

sqlmesh/core/engine_adapter/base.py

@@ -119,6 +119,7 @@ class EngineAdapter:
     MAX_IDENTIFIER_LENGTH: t.Optional[int] = None
     ATTACH_CORRELATION_ID = True
     SUPPORTS_QUERY_EXECUTION_TRACKING = False
+    SUPPORTS_METADATA_TABLE_LAST_MODIFIED_TS = False
 
     def __init__(
         self,
@@ -2927,6 +2928,9 @@ def _check_identifier_length(self, expression: exp.Expression) -> None:
                     f"Identifier name '{name}' (length {name_length}) exceeds {self.dialect.capitalize()}'s max identifier limit of {self.MAX_IDENTIFIER_LENGTH} characters"
                 )
 
+    def get_table_last_modified_ts(self, table_names: t.List[TableName]) -> t.List[int]:
+        raise NotImplementedError()
+
 
 class EngineAdapterWithIndexSupport(EngineAdapter):
     SUPPORTS_INDEXES = True

sqlmesh/core/engine_adapter/bigquery.py

@@ -755,6 +755,28 @@ def table_exists(self, table_name: TableName) -> bool:
         except NotFound:
             return False
 
+    def get_table_last_modified_ts(self, table_names: t.List[TableName]) -> t.List[int]:
+        from sqlmesh.utils.date import to_timestamp
+
+        datasets_to_tables: t.DefaultDict[str, t.List[str]] = defaultdict(list)
+        for table_name in table_names:
+            table = exp.to_table(table_name)
+            datasets_to_tables[table.db].append(table.name)
+
+        results = []
+
+        for dataset, tables in datasets_to_tables.items():
+            query = (
+                f"SELECT TIMESTAMP_MILLIS(last_modified_time) FROM `{dataset}.__TABLES__` WHERE "
+            )
+            for i, table_name in enumerate(tables):
+                query += f"TABLE_ID = '{table_name}'"
+                if i < len(tables) - 1:
+                    query += " OR "
+            results.extend(self.fetchall(query))
+
+        return [to_timestamp(row[0]) for row in results]
+
     def _get_table(self, table_name: TableName) -> BigQueryTable:
         """
         Returns a BigQueryTable object for the given table name.

sqlmesh/core/engine_adapter/snowflake.py

@@ -54,6 +54,7 @@ class SnowflakeEngineAdapter(GetCurrentCatalogFromFunctionMixin, ClusteredByMixi
     SUPPORTS_MANAGED_MODELS = True
     CURRENT_CATALOG_EXPRESSION = exp.func("current_database")
     SUPPORTS_CREATE_DROP_CATALOG = True
+    SUPPORTS_METADATA_TABLE_LAST_MODIFIED_TS = True
     SUPPORTED_DROP_CASCADE_OBJECT_KINDS = ["DATABASE", "SCHEMA", "TABLE"]
     SCHEMA_DIFFER_KWARGS = {
         "parameterized_type_defaults": {
@@ -669,3 +670,18 @@ def close(self) -> t.Any:
             self._connection_pool.set_attribute(self.SNOWPARK, None)
 
         return super().close()
+
+    def get_table_last_modified_ts(self, table_names: t.List[TableName]) -> t.List[int]:
+        from sqlmesh.utils.date import to_timestamp
+
+        num_tables = len(table_names)
+
+        query = "SELECT LAST_ALTERED FROM INFORMATION_SCHEMA.TABLES WHERE"
+        for i, table_name in enumerate(table_names):
+            table = exp.to_table(table_name)
+            query += f"""(TABLE_NAME = '{table.name}' AND TABLE_SCHEMA = '{table.db}' AND TABLE_CATALOG = '{table.catalog}')"""
+            if i < num_tables - 1:
+                query += " OR "
+
+        result = self.fetchall(query)
+        return [to_timestamp(row[0]) for row in result]

sqlmesh/core/plan/evaluator.py

@@ -258,6 +258,7 @@ def visit_backfill_stage(self, stage: stages.BackfillStage, plan: EvaluatablePla
             allow_additive_snapshots=plan.allow_additive_models,
             selected_snapshot_ids=stage.selected_snapshot_ids,
             selected_models=plan.selected_models,
+            is_restatement=bool(plan.restatements),
         )
         if errors:
             raise PlanError("Plan application failed.")

sqlmesh/core/scheduler.py

@@ -251,7 +251,9 @@ def evaluate(
             **kwargs,
         )
 
-        self.state_sync.add_interval(snapshot, start, end, is_dev=not is_deployable)
+        self.state_sync.add_interval(
+            snapshot, start, end, is_dev=not is_deployable, last_altered_ts=now_timestamp()
+        )
         return audit_results
 
     def run(
@@ -335,6 +337,7 @@ def batch_intervals(
         deployability_index: t.Optional[DeployabilityIndex],
         environment_naming_info: EnvironmentNamingInfo,
         dag: t.Optional[DAG[SnapshotId]] = None,
+        is_restatement: bool = False,
     ) -> t.Dict[Snapshot, Intervals]:
         dag = dag or snapshots_to_dag(merged_intervals)
 
@@ -367,6 +370,7 @@ def batch_intervals(
                 deployability_index,
                 default_dialect=adapter.dialect,
                 default_catalog=self.default_catalog,
+                is_restatement=is_restatement,
             )
 
             intervals = self._check_ready_intervals(
@@ -422,6 +426,7 @@ def run_merged_intervals(
         run_environment_statements: bool = False,
         audit_only: bool = False,
         auto_restatement_triggers: t.Dict[SnapshotId, t.List[SnapshotId]] = {},
+        is_restatement: bool = False,
     ) -> t.Tuple[t.List[NodeExecutionFailedError[SchedulingUnit]], t.List[SchedulingUnit]]:
         """Runs precomputed batches of missing intervals.
 
@@ -455,9 +460,12 @@ def run_merged_intervals(
         snapshot_dag = full_dag.subdag(*selected_snapshot_ids_set)
 
         batched_intervals = self.batch_intervals(
-            merged_intervals, deployability_index, environment_naming_info, dag=snapshot_dag
+            merged_intervals,
+            deployability_index,
+            environment_naming_info,
+            dag=snapshot_dag,
+            is_restatement=is_restatement,
         )
-
         self.console.start_evaluation_progress(
             batched_intervals,
             environment_naming_info,
@@ -956,6 +964,7 @@ def _check_ready_intervals(
                     python_env=signals.python_env,
                     dialect=snapshot.model.dialect,
                     path=snapshot.model._path,
+                    snapshot=snapshot,
                     kwargs=kwargs,
                 )
             except SQLMeshError as e:

sqlmesh/core/signal.py

@@ -1,8 +1,14 @@
 from __future__ import annotations
 
-
+import typing as t
 from sqlmesh.utils import UniqueKeyDict, registry_decorator
 
+if t.TYPE_CHECKING:
+    from sqlmesh.core.context import ExecutionContext
+    from sqlmesh.core.snapshot.definition import Snapshot
+    from sqlmesh.utils.date import DatetimeRanges
+    from sqlmesh.core.snapshot.definition import DeployabilityIndex
+
 
 class signal(registry_decorator):
     """Specifies a function which intervals are ready from a list of scheduled intervals.
@@ -33,3 +39,39 @@ class signal(registry_decorator):
 
 
 SignalRegistry = UniqueKeyDict[str, signal]
+
+
+@signal()
+def freshness(batch: DatetimeRanges, snapshot: Snapshot, context: ExecutionContext) -> bool:
+    adapter = context.engine_adapter
+    if context.is_restatement or not adapter.SUPPORTS_METADATA_TABLE_LAST_MODIFIED_TS:
+        return True
+
+    deployability_index = context.deployability_index or DeployabilityIndex.all_deployable()
+
+    last_altered_ts = (
+        snapshot.last_altered_ts
+        if deployability_index.is_deployable(snapshot)
+        else snapshot.dev_last_altered_ts
+    )
+    if not last_altered_ts:
+        return True
+
+    parent_snapshots = {context.snapshots[p.name] for p in snapshot.parents}
+    if len(parent_snapshots) != len(snapshot.node.depends_on) or not all(
+        p.is_external for p in parent_snapshots
+    ):
+        # The mismatch can happen if e.g an external model is not registered in the project
+        return True
+
+    # Finding new data means that the upstream depedencies have been altered
+    # since the last time the model was evaluated
+    upstream_dep_has_new_data = any(
+        upstream_last_altered_ts > last_altered_ts
+        for upstream_last_altered_ts in adapter.get_table_last_modified_ts(
+            [p.name for p in parent_snapshots]
+        )
+    )
+
+    # Returning true is a no-op, returning False nullifies the batch so the model will not be evaluated.
+    return upstream_dep_has_new_data

sqlmesh/core/snapshot/definition.py

@@ -185,6 +185,8 @@ class SnapshotIntervals(PydanticModel):
     intervals: Intervals = []
     dev_intervals: Intervals = []
     pending_restatement_intervals: Intervals = []
+    last_altered_ts: t.Optional[int] = None
+    dev_last_altered_ts: t.Optional[int] = None
 
     @property
     def snapshot_id(self) -> t.Optional[SnapshotId]:
@@ -205,6 +207,12 @@ def add_dev_interval(self, start: int, end: int) -> None:
     def add_pending_restatement_interval(self, start: int, end: int) -> None:
         self._add_interval(start, end, "pending_restatement_intervals")
 
+    def update_last_altered_ts(self, last_altered_ts: t.Optional[int]) -> None:
+        self._update_last_altered_ts(last_altered_ts, "last_altered_ts")
+
+    def update_dev_last_altered_ts(self, last_altered_ts: t.Optional[int]) -> None:
+        self._update_last_altered_ts(last_altered_ts, "dev_last_altered_ts")
+
     def remove_interval(self, start: int, end: int) -> None:
         self._remove_interval(start, end, "intervals")
 
@@ -224,6 +232,13 @@ def _add_interval(self, start: int, end: int, interval_attr: str) -> None:
         target_intervals = merge_intervals([*target_intervals, (start, end)])
         setattr(self, interval_attr, target_intervals)
 
+    def _update_last_altered_ts(
+        self, last_altered_ts: t.Optional[int], last_altered_attr: str
+    ) -> None:
+        if last_altered_ts:
+            existing_last_altered_ts = getattr(self, last_altered_attr)
+            setattr(self, last_altered_attr, max(existing_last_altered_ts or 0, last_altered_ts))
+
     def _remove_interval(self, start: int, end: int, interval_attr: str) -> None:
         target_intervals = getattr(self, interval_attr)
         target_intervals = remove_interval(target_intervals, start, end)
@@ -713,6 +728,10 @@ class Snapshot(PydanticModel, SnapshotInfoMixin):
     dev_table_suffix: str = "dev"
     table_naming_convention: TableNamingConvention = TableNamingConvention.default
     forward_only: bool = False
+    # Physical table last modified timestamp, not to be confused with the "updated_ts" field
+    # which is for the snapshot record itself
+    last_altered_ts: t.Optional[int] = None
+    dev_last_altered_ts: t.Optional[int] = None
 
     @field_validator("ttl")
     @classmethod
@@ -751,6 +770,7 @@ def hydrate_with_intervals_by_version(
             )
             for interval in snapshot_intervals:
                 snapshot.merge_intervals(interval)
+
             result.append(snapshot)
 
         return result
@@ -957,12 +977,20 @@ def merge_intervals(self, other: t.Union[Snapshot, SnapshotIntervals]) -> None:
             if not apply_effective_from or end <= effective_from_ts:
                 self.add_interval(start, end)
 
+        if other.last_altered_ts:
+            self.last_altered_ts = max(self.last_altered_ts or 0, other.last_altered_ts)
+
         if self.dev_version == other.dev_version:
             # Merge dev intervals if the dev versions match which would mean
             # that this and the other snapshot are pointing to the same dev table.
             for start, end in other.dev_intervals:
                 self.add_interval(start, end, is_dev=True)
 
+            if other.dev_last_altered_ts:
+                self.dev_last_altered_ts = max(
+                    self.dev_last_altered_ts or 0, other.dev_last_altered_ts
+                )
+
         self.pending_restatement_intervals = merge_intervals(
             [*self.pending_restatement_intervals, *other.pending_restatement_intervals]
         )
@@ -1081,6 +1109,7 @@ def check_ready_intervals(
                     python_env=signals.python_env,
                     dialect=self.model.dialect,
                     path=self.model._path,
+                    snapshot=self,
                     kwargs=kwargs,
                 )
             except SQLMeshError as e:
@@ -2421,6 +2450,7 @@ def check_ready_intervals(
     python_env: t.Dict[str, Executable],
     dialect: DialectType = None,
     path: t.Optional[Path] = None,
+    snapshot: t.Optional[Snapshot] = None,
     kwargs: t.Optional[t.Dict] = None,
 ) -> Intervals:
     checked_intervals: Intervals = []
@@ -2436,6 +2466,7 @@ def check_ready_intervals(
                 provided_args=(batch,),
                 provided_kwargs=(kwargs or {}),
                 context=context,
+                snapshot=snapshot,
             )
         except Exception as ex:
             raise SignalEvalError(format_evaluated_code_exception(ex, python_env))

sqlmesh/core/state_sync/base.py

@@ -496,6 +496,7 @@ def add_interval(
         start: TimeLike,
         end: TimeLike,
         is_dev: bool = False,
+        last_altered_ts: t.Optional[int] = None,
     ) -> None:
         """Add an interval to a snapshot and sync it to the store.
 
@@ -504,6 +505,7 @@ def add_interval(
             start: The start of the interval to add.
             end: The end of the interval to add.
             is_dev: Indicates whether the given interval is being added while in development mode
+            last_altered_ts: The timestamp of the last modification of the physical table
         """
         start_ts, end_ts = snapshot.inclusive_exclusive(start, end, strict=False, expand=False)
         if not snapshot.version:
@@ -516,6 +518,8 @@ def add_interval(
             dev_version=snapshot.dev_version,
             intervals=intervals if not is_dev else [],
             dev_intervals=intervals if is_dev else [],
+            last_altered_ts=last_altered_ts if not is_dev else None,
+            dev_last_altered_ts=last_altered_ts if is_dev else None,
         )
         self.add_snapshots_intervals([snapshot_intervals])
 

sqlmesh/core/state_sync/db/facade.py

@@ -381,8 +381,9 @@ def add_interval(
         start: TimeLike,
         end: TimeLike,
         is_dev: bool = False,
+        last_altered_ts: t.Optional[int] = None,
     ) -> None:
-        super().add_interval(snapshot, start, end, is_dev)
+        super().add_interval(snapshot, start, end, is_dev, last_altered_ts)
 
     @transactional()
     def add_snapshots_intervals(self, snapshots_intervals: t.Sequence[SnapshotIntervals]) -> None: