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Paul Joseph Davis commented on COUCHDB-800: ------------------------------------------- Odd. When I checked this morning it was still in couch_file as a 1 byte offset instead of 5. I didn't spend too much time reading though so maybe its a subtlety somewhere else. The test itself would be as easy as writing a header larger than 4K and checking the byte boundary position. > Problem when writing larger than 4kb file headers > ------------------------------------------------- > > Key: COUCHDB-800 > URL: https://issues.apache.org/jira/browse/COUCHDB-800 > Project: CouchDB > Issue Type: Bug > Components: Database Core > Affects Versions: 0.11 > Reporter: Damien Katz > Assignee: Damien Katz > Fix For: 0.11.1, 0.12 > > > From Andrey Somov: > Hi, > while reading the CouchDB source I found a question in couch_file.erl, > I am not sure whether it is a bug or not. > Lines 297-311: > handle_call({write_header, Bin}, _From, #file{fd=Fd, eof=Pos}=File) -> > BinSize = size(Bin), > case Pos rem ?SIZE_BLOCK of > 0 -> > Padding = <<>>; > BlockOffset -> > Padding = <<0:(8*(?SIZE_BLOCK-BlockOffset))>> > end, > FinalBin = [Padding, <<1, BinSize:32/integer>> | make_blocks(1, [Bin])], > case file:write(Fd, FinalBin) of > ok -> > {reply, ok, File#file{eof=Pos+iolist_size(FinalBin)}}; > Error -> > {reply, Error, File} > end; > Because <<1, BinSize:32/integer>> occupies 5 bytes make_blocks() shall > use offset=5, but the offset is only 1. > (it should be make_blocks(5, [Bin])) > Since the header is smaller then 4k there is no difference and it > works (the tests succeed with both 1 and 5). But it makes it more > difficult to understand the code for those who study the source to > understand how it works. > - > Thank you, > Andrey -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.