I think the reason for that is that Protobuf doesn’t provide streaming parsers (yet). As the Protobuf based protocol stored all samples in a single message, thi

I think the reason for that is that Protobuf doesn’t provide streaming parsers (yet). As the Protobuf based protocol stored all samples in a single message, this meant that both the client and server had to allocate lots of memory when sending/receiving metrics. With the text based protocol this was never an issue, as the process that does the scraping can ingest metrics line by line.