Badger writes get blocked (maybe stalled)

[jarifibrahim]

What version of Go are you using (go version)?

$ go version
go 1.13

What version of Badger are you using?

v2.0.0

Does this issue reproduce with the latest master?

NO

What did you do?

Run the script https://gist.github.com/jarifibrahim/5ec4983a308e67f116c4ca223344f134#file-main-go

What did you expect to see?

Writes working.

What did you see instead?

The writes were blocked. As seen here https://gist.github.com/jarifibrahim/5ec4983a308e67f116c4ca223344f134#file-output-txt no writes were done for more than an hour.

[jarifibrahim]

The issue seems to be because of value log GC. I noticed that the GC gets blocked and so the writes are also blocked. Commenting out this line https://gist.github.com/jarifibrahim/5ec4983a308e67f116c4ca223344f134#file-main-go-L88 seems to unblock the writes.

[jarifibrahim]

The script https://gist.github.com/jarifibrahim/5ec4983a308e67f116c4ca223344f134 gets blocked until value log GC is completed. In Badger v2.0.0 we had issue with the cache because of which all bloom filters were being read from the file. Reading bloom filters from the file is very slow and expensive in terms of CPU and disk. This issue was fixed via #1260 .

The newer versions of badger have a separate cache for bloom filters.