dap_meta - where did it go? Canvas Data 2

[DanL]

After updating to the latest and greatest Canvas Data 2 dap client cli version, I notice the dap_meta table (which stored the timestamps of when all the tables were last updated) seems to have been renamed to dap_meta_backup, and there is no replacement dap_meta table being populated.

Anyone else noticed this?  Did this data move elsewhere?

Appreciate any insight you can provide.

[LeventeHunyadi]

Newer versions of DAP client library keep synchronization state in the table table_sync. For database engines that support schemas (e.g. PostgreSQL), you find this table in the schema instructure_dap. For database engines that don't support schemas (e.g. MySQL), the table is referred to by its composite name instructure_dap__table_sync.

Information previously in dap_meta is automatically migrated to table_sync when DAP client library is updated.

[DanL]

Thanks so much LeventeHunyadi! Super helpful!

Do you happen to know what the schema_version field is all about?

[LeventeHunyadi]

Each table has a schema version. For example, the schema version of attachments is 3, that of users is 2 and that of wikis is 1. Whenever the schema of a table changes, e.g. a new column is added or a column is deleted, the schema version is incremented. When DAP CLI synchronizes data, it checks schema version against the value reported by DAP API. If DAP CLI has a lower schema version locally, it has to run a series of SQL statements to transform the local state to the exact remote state that DAP has. The series of SQL statements is produced by comparing the schema returned by DAP API against the schema that the database has locally.