Please help me debugging because Dexie is dead after doing db.delete() then db.open() in Electron app #2191

laukaichung · 2025-08-27T01:39:36Z

laukaichung
Aug 27, 2025

db.ts:

Dexie.debug = true;
export class MySubClassedDexie extends Dexie {
  constructor() {
    super("myDatabase");
  }

  this.on(
      "ready",
      async () => {
         try{
          console.log("ready");
          const count = await db.teams.count();
          console.log(count);
          if (count === 0) {
             console.log("populating")
            populateDb()
          }
          console.log("populated");
         }catch(e){
           console.error(e) 
        }
      },
      true,
    );

   this.on("blocked", () => {
      console.log("blocked");
    });
}

Here is the delete function:

export async function deleteAll() {
  if (db.isOpen()) {
    db.close();
    console.log("closed");
  }
  await db.delete();
  console.log("deleted");
  await db.open(); <<---
  console.log("opened");
  return true;
}

If you run it the first time after a version upgrade, it works. But when the app is restarted, running this delete function would make the Dexie fails.

The console would show this:

closed
deleted
ready

So it looks like Dexie fails to open() after delete(). It reaches the "db.on("ready")" listener, but it fails to run await db.teams.count(). No errors are thrown, and the this.on("blocked", ...) handler is not triggered.

Deleting the database manually via the Chrome Inspector doesn’t resolve the issue. Increasing the version number and reloading fixes it, but the problem reappears when restarting the app and running the delete function.

Could you please guide me on how to debug this issue? There are no errors, and I have no clue what’s causing it. It suddenly appeared yesterday. The error occurred in v4.0x, and I updated it to v4.2 after the issue.

Environment

Dexie: ^4.2.1-rc.1
Dexie-related packages: dexie-export-import: ^4.1.4, dexie-react-hooks: ^4.2.0
Platform: Electron

Answered by laukaichung

Aug 28, 2025

Closed. I need to use the vipDb provided by the this.on("ready", (vipDb)) listener in order to prevent any db actions in that listener from being blocked.

View full answer

laukaichung · 2025-08-28T14:58:54Z

laukaichung
Aug 28, 2025
Author

Closed. I need to use the vipDb provided by the this.on("ready", (vipDb)) listener in order to prevent any db actions in that listener from being blocked.

1 reply

dfahlander Aug 28, 2025
Maintainer

That's right. Since all calls to db are blocked until db.on('ready') callbacks all resolves, they themselves need a "vip" instance of Dexie (that doesn't block) - otherwise a deadlock may occur. That vip instance is provided as the argument to the callback of db.on('ready').

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Please help me debugging because Dexie is dead after doing db.delete() then db.open() in Electron app #2191

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Aug 27, 2025

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Aug 28, 2025
Author

dfahlander Aug 28, 2025
Maintainer