Yeah. Since my code works in blocks, read/compress/encrypt/write, loop. Almost all the real data was being written to the compressed file, however any finalization and flushing of the stream wasn't occurring (since the encrypt was failing) so the last bit of any SQLite database wouldn't be written.
I'm guessing that also contributes to how infrequent I saw a problem. -----Original Message----- From: sqlite-users-boun...@sqlite.org [mailto:sqlite-users-boun...@sqlite.org] On Behalf Of Allen Fowler Sent: Thursday, May 28, 2009 5:17 PM To: General Discussion of SQLite Database; kennethinbox-sql...@yahoo.com Subject: Re: [sqlite] corrupt database recovery > I think I found my defect: my old stress tests was based on doing > compression/encryptions/decryption/decompression passes on files of random > sizes; so I would do about a 10 million passes or so and say...that's pretty > good. > > Well...a more structured test exposed the problem and it was this: > > The feof() does return true until you attempt to read PAST the end of a > file. So the code worked great until the file's length was a multiple of the > buffer size (in my case 262,144 bytes). As you can imagine that doesn't > happen too often in the real world. > > Since I assumed that a feof would return true where there wasn't any more > data in the file, I would start another pass at reading a chunk of data > (which wouldn't find anything) and run thru the compression/encryption code. > The compression code worked handled it correctly, but the encryption > required that a DWORD boundary (blowfish) and since 0 is on such a boundary > but at the wrong end...it would fail. > But was causing the DB to be corrupt, but a dump to work fine? What structure was getting damaged? _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
