Removing valid installations from the database

[sdsanches]

For some time now some customers have complained that they do not receive push notifications correctly, we carried out the test here office, on our devices everything worked perfectly.

With the increase in complaints, we investigated more deeply, and through the parse-dashboard we identified that periodically, the installations were simply removed from the database, when opening the app again, the installation was created again for the device.

This ends up being extremely bad, as only users who opened the app in the last 2 or 3 days receive notifications, since the other installations have disappeared from the database.

I've read and researched a lot on the subject, here is a discussion that apparently talks about the same problem.

#6052

First I updated the parse-server to the latest version @4.3.0

It didn't work, so I decided to disable the feature to perform a test, I set PARSE_SERVER_CLEANUP_INVALID_INSTALLATIONS = 0

My server installation runs on Ubuntu 16.02, so I did it as follows:
export PARSE_SERVER_CLEANUP_INVALID_INSTALLATIONS=0

It also did not solve the problem, the installations continued to be removed ...
I went straight to the code and commented everything related to the devicesToRemove variable in the StatusHandler.js class

It didn't solve either ...

I really don't know what else to do to solve the case ... I believe the problem is related to some routine that the parse-server performs, but I haven't figured out how to block it.

Has anyone else observed this behavior?

Any idea how to solve?

The application has about 90% of installations for Android, the code I use to register with the client is as follows:

FirebaseInstanceId.getInstance (). GetInstanceId (). AddOnSuccessListener (new OnSuccessListener <InstanceIdResult> () {
            @Override
            public void onSuccess (InstanceIdResult instanceIdResult) {
                String token = instanceIdResult.getToken ();
                ParseInstallation.getCurrentInstallation (). SetDeviceToken (token);
                ParseInstallation.getCurrentInstallation (). SaveInBackground ();
            }
        });

On the server side, I start it as follows:

var api = new ParseServer ({

        databaseURI: json.apps [i] .databaseURL,
        appId: json.apps [i] .appId,
        masterKey: json.apps [i] .masterKey, // Add your master key here. Keep it secret!
        clientKey: json.apps [i] .clientKey,
        serverURL: json.apps [i] .serverURL,
        verbose: true,
        push: {
          android: {
            apiKey: json.apps [i] .gcmApiKey
          },
          ios:
             [{
                 pfx: json.apps [i] .pathCerDeviOS, // P12 file only
                 bundleId: json.apps [i] .bundleID, // change to match bundleId
                 production: false // dev certificate
             },
             {
                 pfx: json.apps [i] .pathCerReleaseiOS, // P12 file only
                 bundleId: json.apps [i] .bundleID, // change to match bundleId
                 production: true // release certificate
             }]
        }
      });

      app.use (mountPath, api);

[davimacedo]

Was PARSE_SERVER_CLEANUP_INVALID_INSTALLATIONS enabled for your app before all these tests?

[sdsanches]

Before carrying out the tests, I had never changed this flag, so I researched it, I believe it will be active by default.

[davimacedo]

That's strange. Can you reproduce the behavior with your own simulator/device?

[davimacedo]

BTW It is not active by default.

[sdsanches]

So maybe the problem is not related to the PARSE_SERVER_CLEANUP_INVALID_INSTALLATIONS flag.

I went this way because it seems to me to be the only routine in the parse that would remove installations from the database.

But anyway, the installs are removed from my database, is there any other point that I should analyze?

About the tests, they were done with real devices and in the production environment, inclusisise I redid the whole configuration of parse-server and mongodb from scratch, with the updated versions, the same problem continued to occur.

[davimacedo]

I believe you first need to identify if there is some pattern. When you say the installations are removed periodically, you mean all of them? If not, there is any pattern? Can you reproduce the issue (I mean, there are some steps that, if you follow, your installation is also removed)?

[sdsanches]

We were unable to reproduce a specific pattern to simulate the behavior.

But what happens is this:

When downloading the app, the installation record is created in the database.

At the end of the day, we have 500 installations on average, which are new users and old users who opened the app during the day.

We send a push, everyone receives normally.

Within the 48h period (sometimes well before that), all installations are removed from the base, then from 500 active installations, we start over from scratch again.

There is no explanation for the behavior, we have already done countless tests, but we have not been able to identify the cause, the only thing that seems to be related to the problem is the PARSE_SERVER_CLEANUP_INVALID_INSTALLATIONS flag.

[davimacedo]

There is no routine in Parse Server that deletes all installations every day. Do you notice other data also being removed or only installations? How are you hosting Parse Server and the database? How is the CLP for the Installation class? Have you already checked the logs to see if there is some request deleting the installations?

[mman]

@sdsanches Couple comments to help you investigate:

From my understanding of the parse server, the Installations would never be removed, even if you logout, reset password, delete user, the installations just accumulate over time and you need to clean them up manually somehow. There is no code that should delete them. When push fails because user's device is unregistered, the parse server should just delete its respective deviceToken as the app is still on device, just with disabled notifications. I say should as I have not checked the PARSE_SERVER_CLEANUP_INVALID_INSTALLATIONS flag and it's implementation, but if it is deleting installation entries, then it definitely is buggy and wrong. Maybe that is the reason why it is still experimental.

Please examine the logic in your app, whether there is anything that could potentially alter the Installation from the client side. Check whether you are setting any custom key/value objects into your Installation, and if yes examine how is the modified installation saved to the server. There may be client side bugs when saveInBackground hangs because your app is backgrounded, etc. For notifications you are at least setting and saving the deviceToken so investigate how and when this is really pushed to the server. Add save completion callbacks and log what is happening.

On the server, I'd login directly to mongo console and examine indexes associated with the _Installation collection. Mongo allows time based expiring indexes that may delete entries automatically, but Parse Server is definitely not setting up any of these. But perhaps somebody on your team, or parse hosting provider is altering these somehow? Just a guess.

hopefully these help,
Martin

[mman]

@sdsanches In your code, add save completion callback to SaveInBackground() and see what it reports.

                ParseInstallation.getCurrentInstallation (). SaveInBackground ();

[mtrezza]

I've read and researched a lot on the subject, here is a discussion that apparently talks about the same problem. #6052

That thread does not talk about the same problem.

the only thing that seems to be related to the problem is the PARSE_SERVER_CLEANUP_INVALID_INSTALLATIONS flag

This flag only clears the deviceToken field but does not remove the Installation object. It executes a delete operation on the deviceToken field, so it is safe to assume that this cannot cause an Installation object to be deleted.

Any idea how to solve?

Generally:

• check other possible causes of deletion outside of Parse Server, e.g. if you use MongoDB, does the Collection have a TTL index or are there any other external clean-up functions that access the DB?
• inspect Cloud Code and client side for code that deletes objects from the Installation class and how such code may be invoked

If you can controllably reproduce this issue:

• run Parse Server in a debugger and set a selective breakpoint in RestWrite.js or the database adapter you are using to look at the stack trace on deletion

If you cannot controllably reproduce this issue:

• add a beforeDelete cloud code trigger and log the stack trace to find out what caused the deletion
• fork Parse Server and add logs directly to the source at relevant places

@sdsanches Please edit your initial post by using the bug report template provided when opening a new issue. Using the template is necessary to properly look into this and required to open a bug report.

[mtrezza]

I'm closing this as it does not seem to be a Parse Server issue.

For help with Parse Server, here are some resources you can try:

• For code-level questions we recommend Stack Overflow using the parse-platform tag.
• For questions that are not appropriate for the above mentioned sites we recommend our community forum.

Feel free to comment if you have any questions and we can re-open this issue.