ReactNative SQLite error: UNIQUE constraint failed: attach-store.digest

[craftzdog]

Hi, thanks for making such a great library!
I'd like to post an issue regarding pouchdb-adapter-websql-core.

Issue

Can't store multiple documents with same attachment data.
The replication process retrieves docs from _changes feed so multiple attachments are potentially saved at once.
If these have same md5 digest, it will produce an error: UNIQUE constraint failed: attach-store.digest.
Seems like saveAttachment is ignoring existing attachment but not working in this case:
https://github.com/pouchdb/pouchdb/blob/master/packages/node_modules/pouchdb-adapter-websql-core/src/bulkDocs.js#L302

I guess the reason is that attachments are stored in forEach loop where each process doesn't wait for storing the previous attachment:
https://github.com/pouchdb/pouchdb/blob/master/packages/node_modules/pouchdb-adapter-websql-core/src/bulkDocs.js#L212

Info

• Environment: ReactNative
• Platform: iOS
• Adapter: SQLite Adapter for ReactNative (It's my module)
• Server: CouchDB

Reproduce

Sync with multiple attachments with same md5digest.
I encountered this problem while making a SQLite adapter for ReactNative.

[nolanlawson]

My suspicion is that this is related to the ReactNative SQLite adapter and not PouchDB. The reason I suggest that is that we have run our full test suite using:

- node-websql
- WebSQL on Chrome and Safari
- cordova-plugin-sqlite-2

However react-native-sqlite-storage is based on Cordova-sqlite-storage which in my experience has had many bugs and has often failed our test suite (it's largely why I wrote cordova-plugin-sqlite-2).

Could you please run your same test in another SQL-esque implementation (WebSQL, node-websql, cordova-plugin-sqlite-2) and see if the issue persists? If not, then I would guess it's related to react-native-sqlite-storage.

Alternatively, if you can find a test that fails in regular WebSQL, then please provide that test and we will fix it in pouchdb-adapter-websql-core asap. :) You may also be interested to see our existing attachment replication tests here.

[craftzdog]

I made another SQLite module for react native which code base is borrowed from your cordova-plugin-sqlite-2.
It works pretty well!
https://github.com/noradaiko/react-native-sqlite-2

Thanks

[nolanlawson]

Hey, that's awesome! I was hoping it would be useful to extend and use in other environments. :)

…

----- Nolan Lawson http://nolanlawson.com https://github.com/nolanlawson

On Mar 22, 2017 7:17 PM, "Takuya Matsuyama" ***@***.***> wrote: I made another SQLite module for react native which code base is borrowed from your cordova-plugin-sqlite-2 <https://github.com/nolanlawson/cordova-plugin-sqlite-2>. It works pretty well! https://github.com/noradaiko/react-native-sqlite-2 Thanks — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#6037 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AARUwjYkbqPkVWvvB6ipSl78AArBDiT9ks5rodZVgaJpZM4LR1I1> .

[nolanlawson]

I added a mention of your project to the node-websql readme. 😃

By the way, do you still consider it "unstable for storing PouchDB's attachments" (as you say in the readme?). I've run PouchDB's attachment test suite against node-websql and cordova-plugin-sqlite-2 (both Android and iOS) and it passes, so it may be something wrong with the React Native bindings?

[craftzdog]

I'm glad!

I mean that it's unstable with react-native-sqlite-storage.
I've tested storing attachments with react-native-sqlite-2 and UNIQUE constraint error didn't occur.
The difference from cordova-plugin-sqlite-2 is only bridging between JS and native.
There's also a little patch for avoiding Android's problem truncating string including \u0000.
I'd like to run the test suite but I have to learn testing RN.