func (p *Postgres) checkReplStatus(name string) (sent, flushed xlog.Position, err error) {
log := p.log.New("fn", "checkReplStatus", "name", name)
log.Debug("checking replication status")
var s, f pgx.NullString
err = p.db.QueryRow(`
SELECT sent_location, flush_location
FROM pg_stat_replication
WHERE application_name = $1`, name).Scan(&s, &f)
if err != nil && err != pgx.ErrNoRows {
log.Error("error checking replication status", "err", err)
return
}
sent, flushed = xlog.Position(s.String), xlog.Position(f.String)
if err == pgx.ErrNoRows || sent == "" || flushed == "" {
err = ErrNoReplicationStatus
log.Debug("no replication status")
return
}
log.Debug("got replication status", "sent_location", sent, "flush_location", flushed)
return
}
func (p *Postgres) XLogPosition() (xlog.Position, error) {
p.dbMtx.RLock()
defer p.dbMtx.RUnlock()
if !p.running() || p.db == nil {
return "", errors.New("postgres is not running")
}
fn := "pg_last_xlog_replay_location()"
if p.config().Role == state.RolePrimary {
fn = "pg_current_xlog_location()"
}
var res string
err := p.db.QueryRow("SELECT " + fn).Scan(&res)
return xlog.Position(res), err
}