[performance] retry db queries on busy errors (#2025)

* catch SQLITE_BUSY errors, wrap bun.DB to use our own busy retrier, remove unnecessary db.Error type

Signed-off-by: kim <grufwub@gmail.com>

* remove dead code

Signed-off-by: kim <grufwub@gmail.com>

* remove more dead code, add missing error arguments

Signed-off-by: kim <grufwub@gmail.com>

* update sqlite to use maxOpenConns()

Signed-off-by: kim <grufwub@gmail.com>

* add uncommitted changes

Signed-off-by: kim <grufwub@gmail.com>

* use direct calls-through for the ConnIface to make sure we don't double query hook

Signed-off-by: kim <grufwub@gmail.com>

* expose underlying bun.DB better

Signed-off-by: kim <grufwub@gmail.com>

* retry on the correct busy error

Signed-off-by: kim <grufwub@gmail.com>

* use longer possible maxRetries for db retry-backoff

Signed-off-by: kim <grufwub@gmail.com>

* remove the note regarding max-open-conns only applying to postgres

Signed-off-by: kim <grufwub@gmail.com>

* improved code commenting

Signed-off-by: kim <grufwub@gmail.com>

* remove unnecessary infof call (just use info)

Signed-off-by: kim <grufwub@gmail.com>

* rename DBConn to WrappedDB to better follow sql package name conventions

Signed-off-by: kim <grufwub@gmail.com>

* update test error string checks

Signed-off-by: kim <grufwub@gmail.com>

* shush linter

Signed-off-by: kim <grufwub@gmail.com>

* update backoff logic to be more transparent

Signed-off-by: kim <grufwub@gmail.com>

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Signed-off-by: kim <grufwub@gmail.com>

internal/db/session.go

@@ -25,5 +25,5 @@ import (
 
 // Session handles getting/creation of router sessions.
 type Session interface {
-	GetSession(ctx context.Context) (*gtsmodel.RouterSession, Error)
+	GetSession(ctx context.Context) (*gtsmodel.RouterSession, error)
 }