From 5e1639de2bd199874e7cc449d5ebd76871b86c19 Mon Sep 17 00:00:00 2001
From: Dax Raad <d@ironbay.co>
Date: Mon, 26 Jan 2026 12:33:18 -0500
Subject: [PATCH] core: improve conversation loading performance by batching
 database queries

Reduces memory usage and speeds up conversation loading by using pagination
and inArray queries instead of loading all messages at once
---
 packages/opencode/src/session/message-v2.ts | 63 +++++++++++++++------
 1 file changed, 46 insertions(+), 17 deletions(-)

diff --git a/packages/opencode/src/session/message-v2.ts b/packages/opencode/src/session/message-v2.ts
index 6e38edbad6..7d28b912c5 100644
--- a/packages/opencode/src/session/message-v2.ts
+++ b/packages/opencode/src/session/message-v2.ts
@@ -6,7 +6,7 @@ import { Identifier } from "../id/id"
 import { LSP } from "../lsp"
 import { Snapshot } from "@/snapshot"
 import { fn } from "@/util/fn"
-import { Database, eq, desc } from "@/storage/db"
+import { Database, eq, desc, inArray } from "@/storage/db"
 import { MessageTable, PartTable } from "./session.sql"
 import { ProviderTransform } from "@/provider/transform"
 import { STATUS_CODES } from "http"
@@ -608,27 +608,56 @@ export namespace MessageV2 {
   }
 
   export const stream = fn(Identifier.schema("session"), async function* (sessionID) {
-    const rows = Database.use((db) =>
-      db
-        .select()
-        .from(MessageTable)
-        .where(eq(MessageTable.session_id, sessionID))
-        .orderBy(desc(MessageTable.created_at))
-        .all(),
-    )
-    for (const row of rows) {
-      yield {
-        info: row.data,
-        parts: await parts(row.id),
+    const size = 50
+    let offset = 0
+    while (true) {
+      const rows = Database.use((db) =>
+        db
+          .select()
+          .from(MessageTable)
+          .where(eq(MessageTable.session_id, sessionID))
+          .orderBy(desc(MessageTable.created_at))
+          .limit(size)
+          .offset(offset)
+          .all(),
+      )
+      if (rows.length === 0) break
+
+      const ids = rows.map((row) => row.id)
+      const partsByMessage = new Map<string, MessageV2.Part[]>()
+      if (ids.length > 0) {
+        const partRows = Database.use((db) =>
+          db
+            .select()
+            .from(PartTable)
+            .where(inArray(PartTable.message_id, ids))
+            .orderBy(PartTable.message_id, PartTable.id)
+            .all(),
+        )
+        for (const row of partRows) {
+          const list = partsByMessage.get(row.message_id)
+          if (list) list.push(row.data)
+          else partsByMessage.set(row.message_id, [row.data])
+        }
       }
+
+      for (const row of rows) {
+        yield {
+          info: row.data,
+          parts: partsByMessage.get(row.id) ?? [],
+        }
+      }
+
+      offset += rows.length
+      if (rows.length < size) break
     }
   })
 
   export const parts = fn(Identifier.schema("message"), async (message_id) => {
-    const rows = Database.use((db) => db.select().from(PartTable).where(eq(PartTable.message_id, message_id)).all())
-    const result = rows.map((row) => row.data)
-    result.sort((a, b) => (a.id > b.id ? 1 : -1))
-    return result
+    const rows = Database.use((db) =>
+      db.select().from(PartTable).where(eq(PartTable.message_id, message_id)).orderBy(PartTable.id).all(),
+    )
+    return rows.map((row) => row.data)
   })
 
   export const get = fn(