Debugging synchronization status

[matmut7]

Hi,

Thanks for this awesome project!

I am trying it out by coding a small React / Express app. The Express server is virtually identical to the one in vite-starter, it does nothing else.

Sometimes changes in the React client cannot be seen in the serverside DB, even though the Server Sent Events stream seems to be open and working. I'm having a hard time debugging this, I am then wondering if either the client or server library could give some more information on the data replication status, and why it would not be working.

[tantaman]

Sure, there should be some logging to the client and server paths. I'm thinking of adding Winston to both client and server and having it enable when in dev mode.

Also, do you have a repro of this issue I could look at?

[matmut7]

For now I don't, the server DB sometimes gets out of sync and I don't understand when this happens yet. I'll eventually try to look into this and make a minimal reproduction.

[tantaman]

What's the output of '.tables' when you open the server db? And what's the name of the server db? It should be a ~16 byte hex string.

[matmut7]

The DB's ID is 69a2341c552f409faf36e4f771f27cc6 which is hard coded for now but I think it comes from the generation code in vite-starter, but maybe a version from one or two months.

.tables output:

__crsql_siteid
categories
categories__crsql_clock
crsql_master
crsql_tracked_peers
expenses
expenses__crsql_clock
participant_category_coefficients
participant_category_coefficients__crsql_clock
participant_expense_coefficients
participant_expense_coefficients__crsql_clock
participants
participants__crsql_clock

[matmut7]

Changing my DB ID for a new hard coded one seems to make it work again. I'll try to see when it goes out of sync again.

[tantaman]

What about

SELECT * FROM expenses__crsql_clock, SELECT * FROM expenses and SELECT * FROM crsql_changes on the server db?

I see your primary keys look to be auto increment. That's probably not going to work as many devices will assign the same key to rows that are actually not intended to be the same.

The primary key should be some sort of UUID (e.g., nanoid) or something related to the identity of the row.

[matmut7]

I'm so sorry I deleted the previous DB when changing to a new ID 😭
But many thanks for the auto increment problem, I'll change it and let you know if I have any more problems!