Direct I/O Close() shouldn't rewrite the last page #4771
Closed
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Summary: In Direct I/O case, WritableFileWriter::Close() rewrites the last block again, even if there is nothing new. The reason is that, Close() flushes the buffer. For non-direct I/O case, the buffer is empty in this case so it is a no-op. However, in direct I/O case, the partial data in the last block is kept in the buffer because it needs to be rewritten for the next write. This piece of data is flushed again. This commit fixes it by skipping this write out if `pending_sync_` flag shows that there isn't new data sync last sync. Test Plan: Pass all existing tests.
There was a problem hiding this comment.
@siying has imported this pull request. If you are a Facebook employee, you can view this diff on Phabricator.
sagar0
approved these changes
Dec 11, 2018
|
|
siying
changed the title
mm304321141
pushed a commit
to bytedance/terarkdb
that referenced
this pull request
Jan 5, 2022
Summary: In Direct I/O case, WritableFileWriter::Close() rewrites the last block again, even if there is nothing new. The reason is that, Close() flushes the buffer. For non-direct I/O case, the buffer is empty in this case so it is a no-op. However, in direct I/O case, the partial data in the last block is kept in the buffer because it needs to be rewritten for the next write. This piece of data is flushed again. This commit fixes it by skipping this write out if `pending_sync_` flag shows that there isn't new data sync last sync. Pull Request resolved: facebook/rocksdb#4771 Differential Revision: D13420426 Pulled By: siying fbshipit-source-id: 9d39ec9a215b1425d4ed40d85e0eba1f5daa75c6
mm304321141
pushed a commit
to bytedance/terarkdb
that referenced
this pull request
Jan 5, 2022
Summary: In Direct I/O case, WritableFileWriter::Close() rewrites the last block again, even if there is nothing new. The reason is that, Close() flushes the buffer. For non-direct I/O case, the buffer is empty in this case so it is a no-op. However, in direct I/O case, the partial data in the last block is kept in the buffer because it needs to be rewritten for the next write. This piece of data is flushed again. This commit fixes it by skipping this write out if `pending_sync_` flag shows that there isn't new data sync last sync. Pull Request resolved: facebook/rocksdb#4771 Differential Revision: D13420426 Pulled By: siying fbshipit-source-id: 9d39ec9a215b1425d4ed40d85e0eba1f5daa75c6
noobpwnftw
pushed a commit
to noobpwnftw/terarkdb
that referenced
this pull request
Jan 5, 2022
Summary: In Direct I/O case, WritableFileWriter::Close() rewrites the last block again, even if there is nothing new. The reason is that, Close() flushes the buffer. For non-direct I/O case, the buffer is empty in this case so it is a no-op. However, in direct I/O case, the partial data in the last block is kept in the buffer because it needs to be rewritten for the next write. This piece of data is flushed again. This commit fixes it by skipping this write out if `pending_sync_` flag shows that there isn't new data sync last sync. Pull Request resolved: facebook/rocksdb#4771 Differential Revision: D13420426 Pulled By: siying fbshipit-source-id: 9d39ec9a215b1425d4ed40d85e0eba1f5daa75c6
royguo
pushed a commit
to royguo/terarkdb
that referenced
this pull request
Jan 13, 2022
Summary: In Direct I/O case, WritableFileWriter::Close() rewrites the last block again, even if there is nothing new. The reason is that, Close() flushes the buffer. For non-direct I/O case, the buffer is empty in this case so it is a no-op. However, in direct I/O case, the partial data in the last block is kept in the buffer because it needs to be rewritten for the next write. This piece of data is flushed again. This commit fixes it by skipping this write out if `pending_sync_` flag shows that there isn't new data sync last sync. Pull Request resolved: facebook/rocksdb#4771 Differential Revision: D13420426 Pulled By: siying fbshipit-source-id: 9d39ec9a215b1425d4ed40d85e0eba1f5daa75c6
royguo
pushed a commit
to bytedance/terarkdb
that referenced
this pull request
Jan 13, 2022
Summary: In Direct I/O case, WritableFileWriter::Close() rewrites the last block again, even if there is nothing new. The reason is that, Close() flushes the buffer. For non-direct I/O case, the buffer is empty in this case so it is a no-op. However, in direct I/O case, the partial data in the last block is kept in the buffer because it needs to be rewritten for the next write. This piece of data is flushed again. This commit fixes it by skipping this write out if `pending_sync_` flag shows that there isn't new data sync last sync. Pull Request resolved: facebook/rocksdb#4771 Differential Revision: D13420426 Pulled By: siying fbshipit-source-id: 9d39ec9a215b1425d4ed40d85e0eba1f5daa75c6
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Summary: In Direct I/O case, WritableFileWriter::Close() rewrites the last page again, even if there is nothing new. The reason is that, Close() flushes the buffer. For non-direct I/O case, the buffer is empty in this case so it is a no-op. However, in direct I/O case, the partial data in the last page is kept in the buffer because it needs to be rewritten for the next write. This piece of data is flushed again. This commit fixes it by skipping this write out if
pending_sync_flag shows that there isn't new data sync last sync.Test Plan: Pass all existing tests.