perf(db): add published_at composite index for frontend listing queries

.changeset/shaky-berries-stay.md

@@ -0,0 +1,5 @@
+---
+"emdash": patch
+---
+
+Adds composite index on (deleted_at, published_at DESC, id DESC) to eliminate full table scans for frontend listing queries that order by published_at.

packages/core/src/database/migrations/034_published_at_index.ts

@@ -0,0 +1,29 @@
+import type { Kysely } from "kysely";
+import { sql } from "kysely";
+
+import { listTablesLike } from "../dialect-helpers.js";
+
+export async function up(db: Kysely<unknown>): Promise<void> {
+	const tableNames = await listTablesLike(db, "ec_%");
+
+	for (const tableName of tableNames) {
+		const table = { name: tableName };
+
+		await sql`
+			CREATE INDEX ${sql.ref(`idx_${table.name}_deleted_published_id`)}
+			ON ${sql.ref(table.name)} (deleted_at, published_at DESC, id DESC)
+		`.execute(db);
+	}
+}
+
+export async function down(db: Kysely<unknown>): Promise<void> {
+	const tableNames = await listTablesLike(db, "ec_%");
+
+	for (const tableName of tableNames) {
+		const table = { name: tableName };
+
+		await sql`DROP INDEX IF EXISTS ${sql.ref(`idx_${table.name}_deleted_published_id`)}`.execute(
+			db,
+		);
+	}
+}

packages/core/src/database/migrations/runner.ts

@@ -34,6 +34,7 @@ import * as m030 from "./030_widen_scheduled_index.js";
 import * as m031 from "./031_bylines.js";
 import * as m032 from "./032_rate_limits.js";
 import * as m033 from "./033_optimize_content_indexes.js";
+import * as m034 from "./034_published_at_index.js";
 
 const MIGRATIONS: Readonly<Record<string, Migration>> = Object.freeze({
 	"001_initial": m001,
@@ -68,6 +69,7 @@ const MIGRATIONS: Readonly<Record<string, Migration>> = Object.freeze({
 	"031_bylines": m031,
 	"032_rate_limits": m032,
 	"033_optimize_content_indexes": m033,
+	"034_published_at_index": m034,
 });
 
 /** Total number of registered migrations. Exported for use in tests. */

packages/core/src/schema/registry.ts

@@ -595,6 +595,11 @@ export class SchemaRegistry {
 			CREATE INDEX ${sql.ref(`idx_${tableName}_deleted_created_id`)}
 			ON ${sql.ref(tableName)} (deleted_at, created_at DESC, id DESC)
 		`.execute(conn);
+
+		await sql`
+			CREATE INDEX ${sql.ref(`idx_${tableName}_deleted_published_id`)}
+			ON ${sql.ref(tableName)} (deleted_at, published_at DESC, id DESC)
+		`.execute(conn);
 	}
 
 	/**