nickva commented on a change in pull request #806: FEEDBACK ONLY: Compactor
optimize emsort
URL: https://github.com/apache/couchdb/pull/806#discussion_r139167681
##########
File path: src/couch/src/couch_file.erl
##########
@@ -172,21 +175,55 @@ pread_binary(Fd, Pos) ->
pread_iolist(Fd, Pos) ->
case ioq:call(Fd, {pread_iolist, Pos}, erlang:get(io_priority)) of
- {ok, IoList, <<>>} ->
- {ok, IoList};
- {ok, IoList, Md5} ->
- case crypto:hash(md5, IoList) of
- Md5 ->
- {ok, IoList};
- _ ->
- couch_log:emergency("File corruption in ~p at position ~B",
- [Fd, Pos]),
- exit({file_corruption, <<"file corruption">>})
- end;
- Error ->
- Error
+ {ok, IoList, Md5} ->
+ {ok, verify_md5(Fd, Pos, IoList, Md5)};
+ Error ->
+ Error
end.
+
+pread_terms(Fd, PosList) ->
+ {ok, Bins} = pread_binaries(Fd, PosList),
+ Terms = lists:map(fun(Bin) ->
+ couch_compress:decompress(Bin)
+ end, Bins),
+ {ok, Terms}.
+
+
+pread_binaries(Fd, PosList) ->
+ {ok, Data} = pread_iolists(Fd, PosList),
+ {ok, lists:map(fun erlang:iolist_to_binary/1, Data)}.
+
+
+pread_iolists(Fd, PosList) ->
+ case ioq:call(Fd, {pread_iolists, PosList}, erlang:get(io_priority)) of
+ {ok, DataMd5s} ->
+ Data = lists:zipwith(fun(Pos, {IoList, Md5}) ->
+ verify_md5(Fd, Pos, IoList, Md5)
+ end, PosList, DataMd5s),
+ {ok, Data};
+ Error ->
+ Error
+ end.
+
+
+append_terms(Fd, Terms) ->
+ append_terms(Fd, Terms, []).
+
+
+append_terms(Fd, Terms, Options) ->
+ Comp = couch_util:get_value(compression, Options, ?DEFAULT_COMPRESSION),
Review comment:
btree's write_node would grab the compression option from the #btree record
which would still be snappy, but most of it will be provided in
couch_btree:open() which would be read from the config file
`couch_compress:get_compression_method()` and that should be whatever user
specified.
----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on GitHub and use the
URL above to go to the specific comment.
For queries about this service, please contact Infrastructure at:
[email protected]
With regards,
Apache Git Services
