Eliminate inefficiency in form of some extra data downloaded in sync for large files

Aberta
  • Algo errado?
#380 0 comentários 0 reações 0 responsáveis Ver no GitHub

Mantenedores costumam responder em até 1 dia

Ninguém assumiu esta issue ainda.

Avaliação

Dificuldade
4/5
Tempo estimado
3-5 dias
Facilidade para iniciantes
25/100
Tipo de issue
Funcionalidade
Clareza
Precisa de esclarecimento
Status de atividade
Estagnada
Stack de tecnologia
python
Domínio
performance

Direção de pesquisa

No files or tests are named in the payload. Start by locating the Synchronizer class and the downloader it drives in the b2-sdk-python codebase, then trace where a sync download sets the Range header for the first part. The linked B2 integration checklist explains multithreaded downloads. Done means the sync downloader receives the file size and opens the first part with an exact range, avoiding the extra bytes.

Escrita pelo modelo de indexação a partir do texto da issue.

Descrição

help wanted

Large files are downloaded in parts in parallel by all compliant clients, as specified by B2 integration checklist.

The extra data cost is there because when we start streaming the file, we don't (usually) know the size, so we are not requesting an exact range for the download of the first part, but we are sort of requesting the entire file. As soon as the headers come we realize that it's actually a big file, so we start a download session for the further parts of the file. When the data stream for the first part will emit enough data for us to satisfy the first part of the download range, we close the socket HOWEVER because there is some latency on the network, the server has already managed to send us some extra data which is being transmitted from the server to the client while the connection close request is transmitted from the client to the server. These few extra KB are lost.

When in context of sync we do know the file size. Synchronizer could communicate the file size to a specialized implementation of downloader which would then set a clean download part size using the Range header even for the first part.

Linguagem predominante
Python
Estrelas
214
Forks
68
Merge médio
51min
PRs com merge (30d)
6

Preparar o ambiente

Primeiros passos

  1. Leia a issue inteira e depois o guia de contribuição do projeto.
  2. Comente na issue dizendo que vai assumir — evita que duas pessoas façam o mesmo trabalho.
  3. Faça um fork do repositório e trabalhe em uma branch.
  4. Abra um pull request que referencie o número da issue.

Mais de Backblaze/b2-sdk-python

Todas as issues de Backblaze/b2-sdk-python

Issues semelhantes

Mais issues de Python

Receba novas issues na sua caixa de entrada

Um resumo curto de issues do GitHub para quem está começando.