Github user kocolosk commented on a diff in the pull request:
https://github.com/apache/couchdb-couch/pull/185#discussion_r71254154
--- Diff: src/couch_file.erl ---
@@ -524,6 +525,99 @@ handle_info({'EXIT', _, Reason}, Fd) ->
{stop, Reason, Fd}.
+%% first try to read header at end, falling back to chunked reads on
failure
+find_last_header(Fd, FileSize) ->
+ ok = file:advise(Fd, 0, FileSize, dont_need), % minimize disk cache
pollution
--- End diff --
I'm all for smarter use of `posix_fadvise`, but I'm confused about the
advice being given here. On modern Linux systems doesn't this just tell the
kernel to free all pages associated with this file descriptor?
Were you trying to tell the kernel not to cache the reads that you do? I
think that's the intention behind the `no_reuse` setting, but as far as I know
it was never implemented and setting that flag is a noop.
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