config: add --sqlite-max-conns=[int] switch

config.go

@@ -117,6 +117,7 @@ type config struct {
 	MempoolMaxInterval int    `long:"mp-max-interval" description:"The maximum time in seconds between mempool reports (within a couple seconds), regarless of number of new tickets seen." env:"DCRDATA_MEMPOOL_MAX_INTERVAL"`
 	MPTriggerTickets   int    `long:"mp-ticket-trigger" description:"The number minimum number of new tickets that must be seen to trigger a new mempool report." env:"DCRDATA_MP_TRIGGER_TICKETS"`
 	DBFileName         string `long:"dbfile" description:"SQLite DB file name (default is dcrdata.sqlt.db)." env:"DCRDATA_SQLITE_DB_FILE_NAME"`
+	SQLiteMaxConns     int    `long:"sqlite-max-conns" description:"The maximum number of open connections to the SQLite database. By default there is no limit."`
 	AgendasDBFileName  string `long:"agendadbfile" description:"Agendas DB file name (default is agendas.db)." env:"DCRDATA_AGENDAS_DB_FILE_NAME"`
 	ProposalsFileName  string `long:"proposalsdbfile" description:"Proposals DB file name (default is proposals.db)." env:"DCRDATA_PROPOSALS_DB_FILE_NAME"`
 	PoliteiaAPIURL     string `long:"politeiaurl" description:"Defines the root API politeia URL (defaults to https://proposals.decred.org)."`

main.go

@@ -161,6 +161,8 @@ func _main(ctx context.Context) error {
 	log.Infof("SQLite DB successfully opened: %s", cfg.DBFileName)
 	defer baseDB.Close()
 
+	baseDB.DB.SetMaxOpenConns(cfg.SQLiteMaxConns)
+
 	if err = baseDB.ReportHeights(); err != nil {
 		return fmt.Errorf("Possible SQLite corruption: %v", err)
 	}