chore(eap-migration): Add explore foreign key to DiscoverSavedQuery model (#94933)

For the discover saved queries -> explore saved queries migration i've
added an additional `DISCOVER_TRANSACTIONS` dataset type to track which
queries are migrated. To keep track of the original saved query we're
also adding a `explore_query` foreign key field to link the query to its
new explore query. This change requires a migration to add the field to
the model. I've also added a JSON field (`changed_reason`) to the
explore saved query model which we will use to put our reasoning for
dropping certain fields during the migration.

Author: nikkikapadia

migrations_lockfile.txt

@@ -5,9 +5,9 @@ ahead of you.
 To resolve this, rebase against latest master and regenerate your migration. This file
 will then be regenerated, and you should be able to merge without conflicts.
 
-discover: 0001_move_discover_models
+discover: 0002_link_migrated_explore_query_in_discover
 
-explore: 0005_explore_django_json_field
+explore: 0006_add_changed_reason_field_explore
 
 feedback: 0001_squashed_0004_index_together
 

src/sentry/discover/migrations/0002_link_migrated_explore_query_in_discover.py

@@ -0,0 +1,40 @@
+# Generated by Django 5.2.1 on 2025-07-10 15:15
+
+import django.db.models.deletion
+from django.db import migrations
+
+import sentry.db.models.fields.foreignkey
+from sentry.new_migrations.migrations import CheckedMigration
+
+
+class Migration(CheckedMigration):
+    # This flag is used to mark that a migration shouldn't be automatically run in production.
+    # This should only be used for operations where it's safe to run the migration after your
+    # code has deployed. So this should not be used for most operations that alter the schema
+    # of a table.
+    # Here are some things that make sense to mark as post deployment:
+    # - Large data migrations. Typically we want these to be run manually so that they can be
+    #   monitored and not block the deploy for a long period of time while they run.
+    # - Adding indexes to large tables. Since this can take a long time, we'd generally prefer to
+    #   run this outside deployments so that we don't block them. Note that while adding an index
+    #   is a schema change, it's completely safe to run the operation after the code has deployed.
+    # Once deployed, run these manually via: https://develop.sentry.dev/database-migrations/#migration-deployment
+
+    is_post_deployment = False
+
+    dependencies = [
+        ("discover", "0001_move_discover_models"),
+        ("explore", "0006_add_changed_reason_field_explore"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="discoversavedquery",
+            name="explore_query",
+            field=sentry.db.models.fields.foreignkey.FlexibleForeignKey(
+                null=True,
+                on_delete=django.db.models.deletion.SET_NULL,
+                to="explore.exploresavedquery",
+            ),
+        ),
+    ]

src/sentry/discover/models.py

@@ -108,6 +108,12 @@ class DiscoverSavedQuery(Model):
         default=DatasetSourcesTypes.UNKNOWN.value,
         db_default=DatasetSourcesTypes.UNKNOWN.value,
     )
+    # This field is used for the discover transactions -> explore migration.
+    # Migrated discover transactions queries will have this reference along with DISCOVER_TRANSACTIONS as the dataset
+    # in the ExploreSavedQuery.
+    explore_query = FlexibleForeignKey(
+        "explore.ExploreSavedQuery", null=True, on_delete=models.SET_NULL
+    )
 
     class Meta:
         app_label = "discover"

src/sentry/explore/migrations/0006_add_changed_reason_field_explore.py

@@ -0,0 +1,33 @@
+# Generated by Django 5.2.1 on 2025-07-10 14:27
+
+from django.db import migrations, models
+
+from sentry.new_migrations.migrations import CheckedMigration
+
+
+class Migration(CheckedMigration):
+    # This flag is used to mark that a migration shouldn't be automatically run in production.
+    # This should only be used for operations where it's safe to run the migration after your
+    # code has deployed. So this should not be used for most operations that alter the schema
+    # of a table.
+    # Here are some things that make sense to mark as post deployment:
+    # - Large data migrations. Typically we want these to be run manually so that they can be
+    #   monitored and not block the deploy for a long period of time while they run.
+    # - Adding indexes to large tables. Since this can take a long time, we'd generally prefer to
+    #   run this outside deployments so that we don't block them. Note that while adding an index
+    #   is a schema change, it's completely safe to run the operation after the code has deployed.
+    # Once deployed, run these manually via: https://develop.sentry.dev/database-migrations/#migration-deployment
+
+    is_post_deployment = False
+
+    dependencies = [
+        ("explore", "0005_explore_django_json_field"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="exploresavedquery",
+            name="changed_reason",
+            field=models.JSONField(default=None, null=True),
+        ),
+    ]

src/sentry/explore/models.py

@@ -19,10 +19,14 @@
 class ExploreSavedQueryDataset(TypesClass):
     SPANS = 0
     OURLOGS = 1
+    # This is a temporary dataset to be used for the discover -> explore migration.
+    # It will track which queries are generated from discover queries.
+    SEGMENT_SPANS = 101
 
     TYPES = [
         (SPANS, "spans"),
         (OURLOGS, "ourlogs"),
+        (SEGMENT_SPANS, "segment_spans"),
     ]
     TYPE_NAMES = [t[1] for t in TYPES]
 
@@ -86,6 +90,9 @@ class ExploreSavedQuery(DefaultFieldsModel):
     # The version of the prebuilt query. If the version found in the explore_saved_queries.py hardcoded list is greater, then the saved
     # query out of date and should be updated..
     prebuilt_version = BoundedPositiveIntegerField(null=True, db_default=None)
+    # This field is to be used for the discover -> explore migration. This contains the reason why any part
+    # of the saved query was changed so we can display our reasonings in the UI
+    changed_reason = models.JSONField(null=True, default=None)
 
     class Meta:
         app_label = "explore"