steveloughran commented on code in PR #7732:
URL: https://github.com/apache/hadoop/pull/7732#discussion_r2215981743
##########
hadoop-common-project/hadoop-common/src/site/markdown/filesystem/fsdatainputstream.md:
##########
@@ -665,8 +665,48 @@ support through an explicit `hasCapability()` probe:
Stream.hasCapability("in:readvectored")
```
-Given the HADOOP-18296 problem with `ChecksumFileSystem` and direct buffers,
across all releases,
-it is best to avoid using this API in production with direct buffers.
+#### Buffer Slicing
+
+[HADOOP-18296](https://issues.apache.org/jira/browse/HADOOP-18296),
+_Memory fragmentation in ChecksumFileSystem Vectored IO implementation_
+highlights that `ChecksumFileSystem` (which the default implementation of
`file://`
+subclasses), may return buffers which are sliced subsets of buffers allocated
+through the `allocate()` function passed in.
+
+This will happen during reads with and without range coalescing.
+
+Checksum verification may be disabled by setting the option
+`fs.file.checksum.verify` to true (Hadoop 3.4.2 and later).
Review Comment:
done. also found a separate line where I must have accidentally dictated
into the file in commit 33bbcfa4b042d0677e659569c9ca6fd730707ea2
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: common-issues-unsubscr...@hadoop.apache.org
For queries about this service, please contact Infrastructure at:
us...@infra.apache.org
---------------------------------------------------------------------
To unsubscribe, e-mail: common-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: common-issues-h...@hadoop.apache.org
