[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>

---------

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

internal/web/web.go

@@ -62,7 +62,7 @@ const (
 type Module struct {
 	processor    *processing.Processor
 	eTagCache    cache.Cache[string, eTagCacheEntry]
-	isURIBlocked func(context.Context, *url.URL) (bool, db.Error)
+	isURIBlocked func(context.Context, *url.URL) (bool, error)
 }
 
 func New(db db.DB, processor *processing.Processor) *Module {