Merge pull request #2143 from authzed/add-pg-watch-api-index

adds postgres index to support efficient querying via Watch API

internal/datastore/postgres/migrations/zz_migration.0020_add_watch_api_index.go

@@ -0,0 +1,23 @@
+package migrations
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/jackc/pgx/v5"
+)
+
+const addWatchAPIIndexToRelationTupleTable = `CREATE INDEX CONCURRENTLY IF NOT EXISTS ix_watch_index ON relation_tuple (created_xid);`
+
+func init() {
+	if err := DatabaseMigrations.Register("add-watch-api-index-to-relation-tuple-table", "add-metadata-to-transaction-table",
+		func(ctx context.Context, conn *pgx.Conn) error {
+			if _, err := conn.Exec(ctx, addWatchAPIIndexToRelationTupleTable); err != nil {
+				return fmt.Errorf("failed to add watch API index to relation tuple table: %w", err)
+			}
+			return nil
+		},
+		noTxMigration); err != nil {
+		panic("failed to register migration: " + err.Error())
+	}
+}