RandomAccessFileReader::MultiRead() should not return read bytes not read #8941
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…read Summary: Right now, if underlying read returns fewer bytes than asked for, RandomAccessFileReader::MultiRead() still returns those in the buffer to upper layer. This can be a surprise to upper layer. This is unlikely to cause incorrect data. To cause incorrect data, checksum checking in upper layer should pass with short reads, whose chance is low. Test Plan: Run stress tests for a while
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@siying has imported this pull request. If you are a Facebook employee, you can view this diff on Phabricator. |
anand1976
approved these changes
Sep 21, 2021
| @@ -296,8 +296,14 @@ IOStatus RandomAccessFileReader::MultiRead(const IOOptions& opts, | |||
| r.status = fs_r.status; | |||
| if (r.status.ok()) { | |||
| uint64_t offset = r.offset - fs_r.offset; | |||
| size_t len = std::min(r.len, static_cast<size_t>(fs_r.len - offset)); | |||
| r.result = Slice(fs_r.scratch + offset, len); | |||
| if (fs_r.result.size() <= offset) { | |||
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This pull request has been merged in fcce1f2. |
pdillinger
pushed a commit
that referenced
this pull request
Sep 23, 2021
…read (#8941) Summary: Right now, if underlying read returns fewer bytes than asked for, RandomAccessFileReader::MultiRead() still returns those in the buffer to upper layer. This can be a surprise to upper layer. This is unlikely to cause incorrect data. To cause incorrect data, checksum checking in upper layer should pass with short reads, whose chance is low. Pull Request resolved: #8941 Test Plan: Run stress tests for a while Reviewed By: anand1976 Differential Revision: D31085780 fbshipit-source-id: 999adf2d6c2712f1323d14bb68b678df59969973
yoori
pushed a commit
to yoori/rocksdb
that referenced
this pull request
Nov 26, 2023
…read (#8941) Summary: Right now, if underlying read returns fewer bytes than asked for, RandomAccessFileReader::MultiRead() still returns those in the buffer to upper layer. This can be a surprise to upper layer. This is unlikely to cause incorrect data. To cause incorrect data, checksum checking in upper layer should pass with short reads, whose chance is low. Pull Request resolved: facebook/rocksdb#8941 Test Plan: Run stress tests for a while Reviewed By: anand1976 Differential Revision: D31085780 fbshipit-source-id: 999adf2d6c2712f1323d14bb68b678df59969973
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Summary: Right now, if underlying read returns fewer bytes than asked for, RandomAccessFileReader::MultiRead() still returns those in the buffer to upper layer. This can be a surprise to upper layer.
This is unlikely to cause incorrect data. To cause incorrect data, checksum checking in upper layer should pass with short reads, whose chance is low.
Test Plan: Run stress tests for a while