On /debug/sqlite, rollback means: a write transaction/savepoint started, but did not commit. SQLite undid the changes made inside that transaction.

In code terms:

BEGIN IMMEDIATE
  do some SQL
  error happens
ROLLBACK

or for savepoints:

SAVEPOINT
  do some SQL
  error/panic/context cancel happens
ROLLBACK TO SAVEPOINT
RELEASE

Current page rollback counts

From http://localhost:58001/debug/sqlite:

syncing.(*Service).DiscoverObjectWithProgress   rollbacks: 33
syncing.(*Server).loadStore                       rollbacks: 2

No current busy failures:

busy: 0 for visible callers

What rollback usually means here

Rollback is not necessarily a SQLite lock problem.

It usually means the operation was interrupted or failed after starting a transaction/savepoint. Common causes:

context canceled

deadline exceeded

peer sync/discovery failed midway

function returned an error

panic/error inside the transaction

savepoint used for temp-table work got unwound

For DiscoverObjectWithProgress, rollbacks can be normal if discovery attempts get canceled, time out, or stop early.

Difference from `busy`

busy means it could not start BEGIN IMMEDIATE because writer lock was unavailable for ~10s.

rollback means it did start, but later the work was undone.

Recap

rollback on /debug/sqlite means SQLite undid a transaction/savepoint instead of committing it.

Current rollbacks: mostly syncing.(*Service).DiscoverObjectWithProgress with 33.

This does not automatically mean lock contention.

The busy column is the direct SQLite lock-timeout signal; currently visible busy is 0 on port 58001.

Current page rollback counts

What rollback usually means here

Difference from busy

Recap

Difference from `busy`