add a composite index for next scheduled

cmd/exp/main.go

@@ -10,15 +10,15 @@ import (
 // Some experimentation code to figure out this API.
 func main() {
 	p := fsrs.DefaultParam()
-	// p.EnableShortTerm = false
-	// p.EnableFuzz = true
-	// p.MaximumInterval = 365 * 5
+	p.EnableShortTerm = false
+	p.EnableFuzz = true
+	p.MaximumInterval = 365 * 5
 	card := fsrs.NewCard()
 	now := time.Now()
 	card.Due = now
 	f := fsrs.NewFSRS(p)
-	card.Stability = 1000000
-	card.Difficulty = 1
+	// card.Stability = 1000000
+	// card.Difficulty = 1
 	card.State = fsrs.New // this needs to be set if changing the stab/diff manually.
 	for range 10 {
 		schedulingCards := f.Repeat(card, card.Due)

db/migrations/000004_composite_idx_schedule.down.sql

@@ -0,0 +1,5 @@
+BEGIN;
+
+DROP INDEX IF EXISTS idx_cards_user_lexicon_scheduled;
+
+COMMIT;

db/migrations/000004_composite_idx_schedule.up.sql

@@ -0,0 +1,6 @@
+BEGIN;
+
+CREATE INDEX IF NOT EXISTS idx_cards_user_lexicon_scheduled
+  ON wordvault_cards (user_id, lexicon_name, next_scheduled);
+
+COMMIT;