It will be deleted when the GC runs. I confirmed that with --js-flags="--expose-gc" and chrome://blob-internals.

I'm getting this report from +mwills. Mitchell can you confirm whether or not you were seeing this?

Yah initially they were being held onto forever because devtools was open.
However, even with devtools closed I still have problems because the blobs I download are not gced. I have code that is more or less:

  download chunk to blob
  save blob to indexedDB
  nolonger reference original blob
  repeat

However, the downloads in /tmp eventually build up and the machine runs out of space in that partition. It looks like potentially the blobs simply aren't getting gced (doing things like opening dev tools sometimes causes the storage usage to drop).

I did a few more tests.

When I run with the --expose-gc flag and call gc() after I remove my reference to the blob the blobs get deleted (space is reclaimed on /tmp and they disappear from chrome://blob-internals/). This seems to indicate that my issue is chrome is not gcing my blobs so blob storage still things there is a reference. Maybe when available space in /tmp becomes low chrome should trigger a GC or something? Although it would be great if there was a way to do it today in stable chrome. Using Blob#close doesn't seem to help at all (not sure if that's been gutted or not).

devtools should not retain anything, please attach a snippet of the code for us to investigate.

To reproduce:
Create a large file called "large": fallocate -l 1GB large
Serve "large" and the attached page in chrome with --js-flags="--expose-gc"
if you watch the available space in /tmp it will go down and then go back up after about 1GB (after the download completes and gc is called). However, if you open up devtools (and wait for the current request to complete) the available space in /tmp will continue to decline until the partition runs out of space.

Deleted: index.html 607 bytes

index.html 607 bytes View Download

Sounds like a devtools bug then? Assigning to pfeldman for triage.

I'm going to make a blob-side bug for gc importance / accounting for large blobs.

Blob-side bug: https://bugs.chromium.org/p/chromium/issues/detail?id=712684

Also relates to https://bugs.chromium.org/p/chromium/issues/detail?id=712693

why was this archived?

(feel free to change back to archived, just wondering why)