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| author | Filipe David Borba Manana <fdmanana@apache.org> | 2010-11-10 21:14:00 +0000 |
|---|---|---|
| committer | Filipe David Borba Manana <fdmanana@apache.org> | 2010-11-10 21:14:00 +0000 |
| commit | 961d81a01f9f5f8f3c6807f143ba0678c14c4a28 (patch) | |
| tree | 87e281c2db294ee89862f070bec342c417542a13 /src/couchdb | |
| parent | 9e53f467f89bc3942f8795f6d07f61d3f5115f88 (diff) | |
Micro optimization: faster header reads (read the whole block at once, so far headers are always smaller than a block). Read time is basically reduced to half.
git-svn-id: https://svn.apache.org/repos/asf/couchdb/trunk@1033714 13f79535-47bb-0310-9956-ffa450edef68
Diffstat (limited to 'src/couchdb')
| -rw-r--r-- | src/couchdb/couch_file.erl | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/src/couchdb/couch_file.erl b/src/couchdb/couch_file.erl index 860c9f4e..a3a728c7 100644 --- a/src/couchdb/couch_file.erl +++ b/src/couchdb/couch_file.erl @@ -486,11 +486,18 @@ find_header(Fd, Block) -> end. load_header(Fd, Block) -> - {ok, <<1>>} = file:pread(Fd, Block*?SIZE_BLOCK, 1), - {ok, <<HeaderLen:32/integer>>} = file:pread(Fd, (Block*?SIZE_BLOCK) + 1, 4), + {ok, <<1, HeaderLen:32/integer, RestBlock/binary>>} = + file:pread(Fd, Block * ?SIZE_BLOCK, ?SIZE_BLOCK), TotalBytes = calculate_total_read_len(1, HeaderLen), - {ok, <<RawBin:TotalBytes/binary>>} = - file:pread(Fd, (Block*?SIZE_BLOCK) + 5, TotalBytes), + case TotalBytes > byte_size(RestBlock) of + false -> + <<RawBin:TotalBytes/binary, _/binary>> = RestBlock; + true -> + {ok, Missing} = file:pread( + Fd, (Block * ?SIZE_BLOCK) + 5 + byte_size(RestBlock), + TotalBytes - byte_size(RestBlock)), + RawBin = <<RestBlock/binary, Missing/binary>> + end, <<Md5Sig:16/binary, HeaderBin/binary>> = iolist_to_binary(remove_block_prefixes(1, RawBin)), Md5Sig = couch_util:md5(HeaderBin), |