Reduce dashboard bootstrap payload

superset/config.py

@@ -282,6 +282,7 @@ def _try_json_readsha(filepath, length):  # pylint: disable=unused-argument
     "ENABLE_EXPLORE_JSON_CSRF_PROTECTION": False,
     "KV_STORE": False,
     "PRESTO_EXPAND_DATA": False,
+    "REDUCE_DASHBOARD_BOOTSTRAP_PAYLOAD": False,
     "SHARE_QUERIES_VIA_KV_STORE": False,
     "TAGGING_SYSTEM": False,
 }

superset/connectors/base/models.py

@@ -27,6 +27,28 @@
 from superset.models.slice import Slice
 from superset.utils import core as utils
 
+METRIC_FORM_DATA_PARAMS = [
+    "metric",
+    "metrics",
+    "metric_2",
+    "percent_metrics",
+    "secondary_metric",
+    "size",
+    "timeseries_limit_metric",
+    "x",
+    "y",
+]
+
+COLUMN_FORM_DATA_PARAMS = [
+    "all_columns",
+    "all_columns_x",
+    "columns",
+    "entity",
+    "groupby",
+    "order_by_cols",
+    "series",
+]
+
 
 class BaseDatasource(
     AuditMixinNullable, ImportMixin
@@ -213,6 +235,70 @@ def data(self) -> Dict[str, Any]:
             "select_star": self.select_star,
         }
 
+    def data_for_slices(self, slices: List[Slice]) -> Dict[str, Any]:
+        """
+        The representation of the datasource containing only the required data
+        to render the provided slices.
+
+        Used to reduce the payload when loading a dashboard.
+        """
+        data = self.data
+        metric_names = set()
+        column_names = set()
+        for slc in slices:
+            form_data = slc.form_data
+
+            # pull out all required metrics from the form_data
+            for param in METRIC_FORM_DATA_PARAMS:
+                for metric in utils.get_iterable(form_data.get(param) or []):
+                    metric_names.add(utils.get_metric_name(metric))
+
+                    if utils.is_adhoc_metric(metric):
+                        column_names.add(
+                            (metric.get("column") or {}).get("column_name")
+                        )
+
+            # pull out all required columns from the form_data
+            for filter_ in form_data.get("adhoc_filters") or []:
+                if filter_["clause"] == "WHERE" and filter_.get("subject"):
+                    column_names.add(filter_.get("subject"))
+
+            for param in COLUMN_FORM_DATA_PARAMS:
+                for column in utils.get_iterable(form_data.get(param) or []):
+                    column_names.add(column)
+
+        filtered_metrics = [
+            metric
+            for metric in data["metrics"]
+            if metric["metric_name"] in metric_names
+        ]
+
+        filtered_columns = [
+            column
+            for column in data["columns"]
+            if column["column_name"] in column_names
+        ]
+
+        del data["description"]
+        data.update({"metrics": filtered_metrics})
+        data.update({"columns": filtered_columns})
+        verbose_map = {"__timestamp": "Time"}
+        verbose_map.update(
+            {
+                metric["metric_name"]: metric["verbose_name"] or metric["metric_name"]
+                for metric in filtered_metrics
+            }
+        )
+        verbose_map.update(
+            {
+                column["column_name"]: column["verbose_name"] or column["column_name"]
+                for column in filtered_columns
+            }
+        )
+        data["verbose_map"] = verbose_map
+
+        return data
+
     @staticmethod
     def filter_values_handler(
         values, target_column_is_numeric=False, is_list_target=False
@@ -353,6 +439,14 @@ def get_extra_cache_keys(  # pylint: disable=no-self-use
         """
         return []
 
+    def __hash__(self) -> int:
+        return hash(self.uid)
+
+    def __eq__(self, other: object) -> bool:
+        if not isinstance(other, BaseDatasource):
+            return NotImplemented
+        return self.uid == other.uid
+
 
 class BaseColumn(AuditMixinNullable, ImportMixin):
     """Interface for column"""

superset/utils/core.py

@@ -1211,6 +1211,17 @@ def split(
     yield s[i:]
 
 
+def get_iterable(x: Any) -> List:
+    """
+    Get an iterable (list) representation of the object.
+
+    :param x: The object
+    :returns: An iterable representation
+    """
+
+    return x if isinstance(x, list) else [x]
+
+
 class TimeRangeEndpoint(str, Enum):
     """
     The time range endpoint types which represent inclusive, exclusive, or unknown.

superset/views/core.py

@@ -17,6 +17,7 @@
 # pylint: disable=C,R,W
 import logging
 import re
+from collections import defaultdict
 from contextlib import closing
 from datetime import datetime, timedelta
 from typing import Any, Callable, cast, Dict, List, Optional, Union
@@ -1788,11 +1789,12 @@ def dashboard(self, dashboard_id):
         dash = qry.one_or_none()
         if not dash:
             abort(404)
-        datasources = set()
+
+        datasources = defaultdict(list)
         for slc in dash.slices:
             datasource = slc.datasource
             if datasource:
-                datasources.add(datasource)
+                datasources[datasource].append(slc)
 
         if config["ENABLE_ACCESS_REQUEST"]:
             for datasource in datasources:
@@ -1807,6 +1809,14 @@ def dashboard(self, dashboard_id):
                         "superset/request_access/?" f"dashboard_id={dash.id}&"
                     )
 
+        # Filter out unneeded fields from the datasource payload
+        datasources_payload = {
+            datasource.uid: datasource.data_for_slices(slices)
+            if is_feature_enabled("REDUCE_DASHBOARD_BOOTSTRAP_PAYLOAD")
+            else datasource.data
+            for datasource, slices in datasources.items()
+        }
+
         dash_edit_perm = check_ownership(
             dash, raise_if_false=False
         ) and security_manager.can_access("can_save_dash", "Superset")
@@ -1854,7 +1864,7 @@ def dashboard(**kwargs):
         bootstrap_data = {
             "user_id": g.user.get_id(),
             "dashboard_data": dashboard_data,
-            "datasources": {ds.uid: ds.data for ds in datasources},
+            "datasources": datasources_payload,
             "common": common_bootstrap_payload(),
             "editMode": edit_mode,
             "urlParams": url_params,

tests/model_tests.py

@@ -22,8 +22,9 @@
 from sqlalchemy.engine.url import make_url
 
 import tests.test_app
-from superset import app
+from superset import app, db as metadata_db
 from superset.models.core import Database
+from superset.models.slice import Slice
 from superset.utils.core import get_example_database, QueryStatus
 
 from .base_tests import SupersetTestCase
@@ -318,3 +319,16 @@ def test_query_with_non_existent_metrics(self):
             tbl.get_query_str(query_obj)
 
         self.assertTrue("Metric 'invalid' does not exist", context.exception)
+
+    def test_data_for_slices(self):
+        tbl = self.get_table_by_name("birth_names")
+        slc = (
+            metadata_db.session.query(Slice)
+            .filter_by(datasource_id=tbl.id, datasource_type=tbl.type)
+            .first()
+        )
+
+        data_for_slices = tbl.data_for_slices([slc])
+        self.assertEquals(len(data_for_slices["columns"]), 0)
+        self.assertEquals(len(data_for_slices["metrics"]), 1)
+        self.assertEquals(len(data_for_slices["verbose_map"].keys()), 2)

tests/utils_tests.py

@@ -36,6 +36,7 @@
     convert_legacy_filters_into_adhoc,
     datetime_f,
     format_timedelta,
+    get_iterable,
     get_or_create_db,
     get_since_until,
     get_stacktrace,
@@ -950,3 +951,8 @@ def test_get_time_range_endpoints(self):
                 get_time_range_endpoints(form_data={"datasource": "1__table"}, slc=slc),
                 (TimeRangeEndpoint.INCLUSIVE, TimeRangeEndpoint.EXCLUSIVE),
             )
+
+    def test_get_iterable(self):
+        self.assertListEqual(get_iterable(123), [123])
+        self.assertListEqual(get_iterable([123]), [123])
+        self.assertListEqual(get_iterable("foo"), ["foo"])