insights: change series_id to string (hash); add index

enterprise/internal/insights/store/store_test.go

@@ -39,12 +39,14 @@ INSERT INTO metadata(metadata) VALUES ('{"hello": "world", "languages": ["Go", "
 SELECT setseed(0.5);
 INSERT INTO series_points(
     time,
+	series_id,
     value,
     metadata_id,
     repo_id,
     repo_name_id,
     original_repo_name_id)
 SELECT time,
+    'somehash',
     random()*80 - 40,
     (SELECT id FROM metadata WHERE metadata = '{"hello": "world", "languages": ["Go", "Python", "Java"]}'),
     2,

migrations/codeinsights/1000000003_insights_series_id.down.sql

@@ -0,0 +1,3 @@
+BEGIN;
+
+COMMIT;

migrations/codeinsights/1000000003_insights_series_id.up.sql

@@ -0,0 +1,10 @@
+BEGIN;
+
+DELETE FROM series_points; -- affects dev environments only, others never had data in this table.
+ALTER TABLE series_points ALTER COLUMN series_id TYPE text;
+ALTER TABLE series_points ALTER COLUMN series_id SET NOT NULL;
+
+-- Give series_id a btree index since we'll be filtering on it very frequently.
+CREATE INDEX series_points_series_id_btree ON series_points USING btree (series_id);
+
+COMMIT;